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— AN ACCOUNT

‘ : OF THE ;
: al eae OF
WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES
BY ,
G.:O, SARS
f VOL. VI
hes | CYCLOPOIDA
PARTS I & II
OITHONIDA, CYCLOPINIDA, CYCLOPID (part).
“aa | | BERGEN
y PUBLISHED BY THE BERGEN MUSEUM
2) : pS ee wha Be hovaas womtac: CHRISTIANIA

Ke ) : 1913

INTRODUCTION.

Under the head Cyclopoida I comprise a number of Copepoda, which on
the whole may be said to be built upon the type of our common fresh-water
fleas (Cyclops), though exhibiting many modifications, both as to their general ap-
pearance and to their habits, the latter affecting chiefly the structure of the oral
parts. The present group, or sub-order, exhibits some relations both to the
Calanoida and to the Harpacticoida, and also shows a certain approach to some
of the other sub-orders distinguished by the present author, especially to the
Notodelphyoida and the Caligoida, though the Cyclopoid type may always be
easily recognisable. Whereas the extensive group Harpacticoida by earlier authors
has generally been comprised within a single family, the Harpacticida, several
families referable to the present sub-order were established very early, though
their real connexion under a common type has not been recognised.

According to the system proposed by Dr. Giesbrecht, the Cyclopoida, like
the Harpacticoida, should be included in the 2nd of his 2 primary divisions, the
so-called Podoplea. This very extensive and heterogeneous group has been divided
by that author into 2 sections, Jsokerandria and Ampharthrandria, according to
the non-prehensile or prehensile character of the anterior antenne in the male,
each section comprising several families, which have been enumerated in his
recent work on the family Asterocheride, p. 57. I am, however, by no means
prepared to adopt this classification, which appears to me quite artificial, like
the primary grouping of the Copepoda into Gymmnoplew and Podoplea. In the
sense here adopted, the sub-order Cyclopoida comprises families referred by Dr.
Giesbrecht partly to the Jsokerandria and partly to the Ampharthrandria, whereas
other families included by that author in the latter section are wholly removed
as types of distinct sub-orders. One of these, the Harpuacticoida, has been treated
of in the preceding volume, the 4 remaining sub-orders, Notodelphyoida, Monstril-
loida, Caligoida and Lerneoida, being reserved for the succeeding volumes of the
present work.

1 — Crustacea.

As mentioned above, the habits of the Cyclopoida are much more varied
than is the case with the Calanoida and Harpacticoida. Some of them, for
instance the species of the genus Oithona, are true pelagic animals, constituting
a chief part of the plankton in almost all regions of the Oceans. Several other
forms, like the Harpacticoida, live near the shores among alge or on a muddy
bottom at different depths, and a great number of forms lead a-more or less
pronounced parasitic existence, attacking different invertebrate animals, in some
instances also fishes. In most cases, however, the parasitism may be said to
be merely temporary, though there are also a few examples of a more permanent
parasitism, for instance in the case of Hrgasilus and Nicothoé. The different mode
and degree of parasitism has a great influence on the structure of the oral parts,
and indeed we have in this feature a good guide for an exact subdivision of this
group of Copepoda. The parasitic forms exhibit, as regards the structure of the oral
parts, 2 well-marked types, both again differing conspicuously from the non-
parasitic forms. We may accordingly divide the Cyclopoida into 3 natural sec-
tions, for which I propose to retain the well-known names: gnathostoma, siphono-
stoma and poecilostoma. These names were first proposed by Thorell, but were
taken in a much wider sense, viz., to divide the entire order Copepoda. I here
restrict them to the group of Copepoda which will be treated of in the present
volume.

As to the general characters distinguishing this group, the external
appearance of the body, as a rule, looks rather different from that found in the
typical Harpacticoida by the very sharp demarcation of the 2 chief divisions of
the body, the anterior one being more or less tumefied, the posterior very narrow.
So far the Cyclopoida more resemble the Calanoida than the Harpacticoida, though
they are easily distinguished from them by the very moveable articulation between
the last 2 trunk-segments, the posterior of which, as a rule, is very small and
firmly connected with the genital segment, so that, at first sight, it has the
appearance of belonging more properly to the posterior than to the anterior
division of the body.

The anterior antenne are, as a rule, more elongated than in the Har-
pacticoida and are composed of a greater number of articulations. There are,
however, also some instances of a more or less great reduction of these limbs,
both in size and in the number of joints.

The posterior antenne are generally simple, without any outer ramus or
exopodite. Only in a few of the parasitic forms is there a slight rudiment of
such a ramus, In several of the poecilostomous Cyclopoida these antenne are

transformed into powerful prehensile organs.

The oral parts, as mentioned above, are of very different structure in
the 3 sections of Cyclopoida.

The natatory legs are, as a rule, shorter and stouter than in the Har-
pacticoida, with the basal part broad and flattened and the rami generally well
developed and subequal in size. ‘The Ist pair are smaller than the succeeding
ones and never prehensile. In a few of the parasitic forms, for instance Cancerilla,
a considerable reduction of the natatory legs is found to have taken place, at
least in the female.

The last pair of legs are always very small and simple in structure,
being in most cases exactly alike in the two sexes.

The ova are carried in 2 ovisacs, which are lateral or even subdorsal,
never, as in the Harpacticoida, ventral. Only in one instance, viz., in our in-
digenous species of Corycwus, have I found only a single ovisac, which, however,
is attached quite dorsally.

The Cyclopoida are well represented also in fresh water by numerous
species of the genus Cyclops and allied forms, and some of the parasitic forms,

for instance Hygasilus, are also true fresh-water animals.

section 1. Gnathostoma.

General Characters.—Anterior antenne in male distinctly hinged. Posterior
antenne without any outer ramus, and carrying on the tip a number of curved
sete. Oral parts adapted for mastication. Masticatory parts of mandibles and
maxille strongly dentate. Maxillipeds not subchelate; the posterior ones smaller
than the anterior, and of the same appearance in the two sexes. Natatory legs
well developed, with both rami generally 3-articulate.

Remarks.—The several forms belonging to this section have generally
been combined within a single family, the Cyclopidw. It is, however, very easy
to distinguish at least 3 well-defined families of gnathostomous Cyclopoida. All
these 3 families are represented in the fauna of Norway, and will be shortly
characterised below.

Fam. |. Ojlthonide.

Characters.—Body slender and of a very delicate structure, with thin
and pellucid integuments. Anterior antenne in female very slender and provided
with long diverging sete; those in male much more robust and distinctly geni-
culate. Posterior antennz: comparatively small, with the number of joints reduced.
Oral parts well developed, and rather different in structure from those in other
Cyclopoida, being partly armed with claw-like spines. Natatory legs with com-
paratively slender 3-articulate rami edged with unusually long sete. Last pair
of legs rudimentary and partly confluent with the corresponding segment. Caudal
rami differing in shape and armature in the two sexes.

Remarks.—This family is founded upon the genus QOithona Baird, which
in several respects differs rather conspicuously from the other genera included
in the present section, and may accordingly be entitled to constitute the type
of a distinct group. We do not know as yet any other genus referable to this
family. The genus Mormonilla of Giesbrecht, it is true, exhibits some resemblance
to Oithona in the general appearance of the body as also in the structure of
the anterior antenne; but the posterior antenne are very different and built
wholly on the type of the Calanoida. The systematic position of this genus is
still very doubtful, though it perhaps may be found to be nearest related to the
Cyclopoida. In this case it must be regarded as the type of a very anomalous
family of the gnathostomous Cyclopoida.

Gen. 1. Oithona, Baird, 1843.

Syn: Sceribella, Dana.

Generic Characters.—Body slender and attenuated, with the anterior
division only slightly dilated, the posterior very narrow, linear in form. Head
defined from the Ist pedigerous segment by a well-marked suture, and generally
produced in front to a sharply-pointed rostrum, wanting, however, in male.
Anterior antenne long and slender, scarcely tapered distally, and composed of a
limited number of joints, some of which are imperfectly defined. Posterior an-
tenne abruptly bent in the middle, and apparently only consisting of 2 joints,
the Ist carrying about in the middle behind a short seta arising from a knob-
like prominence. Mandibular palp with the basal part greatly produced, pediform,
terminating in 2 claw-like spines, inner ramus represented by a very small seti-

ferous appendage attached outside the basal part at some distance from its end,
outer ramus well developed and abruptly reflexed, being composed of 3—4 joints
carrying long plumose sete. Maxille with the masticatory lobe well defined and
carrying a number of sharp claw-like spines accompanied inside by a thick seti-
form appendage, palp lamellar, with the outer distal lobe very small, proximal
lobe well developed, recurved, and provided at the tip with long plumose setz!).
Both pairs of maxillipeds slender and elongated, the anterior ones 5-articulate,
the posterior ones 4-articulate, both carrying long anteriorly-curving spines. Na-
tatory legs with no distinctly developed seta inside the Ist joint of the outer
ramus, apical spine of this ramus very slender and serrate outside, spines of
outer edge more perfectly developed in male than in female. Last pair of legs
represented by a small conical joint terminating in a long seta; another similar
seta issuing from a knob-like prominence on each side of the segment itself,
seems to answer to that arising from the basal joint of these legs in other Cyclo-
poida. Caudal rami in female strongly divergent, with the 2 middle apical sete
much elongated and crossing each other at the base; those in male of quite
normal appearance.

Remarks.—The present genus was established in the year 1843 by Baird,
to include a species, O. plwmifera, taken in the tropical part of the Atlantic.
Another genus with the same name has been established by Alder and Hancock
for a nudibranchiate Mollusc; but as this genus is of younger date than that
of Baird, its name must be changed. The genus Seribella of Dana is identical
with that of Baird, and likewise of later date. Several species of this genus
have in recent times been described from different parts of the Oceans. Thus
Dr. Giesbrecht records no less than 8 species, and some additional species have
been named by other authors. There is, however, still considerable confusion
about the right identification of some of these species, partly owing to their
close relation and partly to the difficulty which is connected with an exact ana-
tomical examination of such delicate and fragile animals. One of the species
described by Dr. Giesbrecht, O. nana, seems in some respects to differ more
conspicuously from the others, and may perhaps be regarded as the type of a
separate, though nearly allied genus, for which the name QOithonina may be
proposed. To the fauna of Norway belong 2 well-defined species, to be de-
scribed below.

1) I have formerly described these 2 lobes as the exopodal and epipodal lobes, but find
that these names cannot properly be retained, since they unquestionably, as is clearly seen in the
present genus, answer to the inner and outer rami of the mandibular palp. As, however, both

these lobes are always attached outside the palp, I find it more appropriate to give them the
indifferent names of proximal and distal outer lobes.

1. OQithona spinirostris, Claus.
(Pl. I & ID).
Oithona spinirostris, Claus, Die freilebenden Copepoden, p. 105, PJ. XI, figs. 4—9.

Syn: Otthona challengeri, Thompson.
ze plumifera, Scott, (not Baird).
= atlantica, Farran.

Specific Characters.— Female. Body exceedingly slender, with the anterior
division narrow fusiform in shape, the greatest width scarcely exceeding 1/3; of
the length and occurring somewhat in front of the middle. No conspicuous plumes
present laterally. Rostrum strong, spiniform, and only very slightly curved, so
as to be visible in the dorsal aspect of the animal. Tail not much shorter than
the anterior division and very narrow; genital segment about the length of the 2
succeeding segments combined, and conspicuously dilated in its anterior part.
Caudal rami nearly as long as the anal segment and rather divergent, seta of
outer edge attached close to the base, the 2 middle apical sete almost twice the
length of the tail. Kye narrow linear in form and of a deep red colour. Anterior
antenns very slender and elongated, reaching, when reflexed, to the end of the
2nd caudal segment, and composed of about 12 more or less distinctly defined
joints of rather unequal length and carrying scattered exceedingly long sete
pointing in different directions. Ist pair of natatory legs with the inner ramus
distinctly 3-articulate, all joints of outer ramus spiniferous outside. 2nd and 3rd
pair with no spine outside the middle joint of the outer ramus, terminal joint of
this ramus, as in the Ist pair, with 2 spines outside. 4th pair with no spines
outside the first 2 joints of the outer ramus and with only a single setiform spine
outside the terminal joint. Ovisacs narrow oblong in form and greatly divergent,
in some cases extending nearly at right angles to the axis of the body, each
sac containing only a limited number of very pellucid ova, generally arranged
in a double row.

Male much smaller than female and of a rather different appearance,
the body being comparatively less slender, with the front obtusely truncate and
wanting any trace of a rostrum. Tail distinctly 5-articulate, with the Ist or
genital segment greatly swollen, to receive the 2 spermatophores. Caudal rami
shorter than the anal segment and not at all divergent, apical setee much shorter
than in female and of quite normal appearance. Anterior antenne scarcely
longer than the anterior division of the body and exhibiting the usual geniculation;
middle section only slightly tumefied, terminal one biarticulate. Natatory legs
with all the joints of the outer ramus spiniferous outside, 3 such spines being

present on the terminal joint in the 2nd and 38rd pairs. Sete of last pair of
legs much sherter than in female.

Body in both sexes highly pellucid and nearly colourless, though in adult
females generally a light orange pigment is seen clothing the oral area and partly
also the sides of the head. A large oil-bubble is often found within the posterior
part of the trunk, and 2 smaller ones at the limit between the head and the
lst pedigerous segment.

Length of adult female 1.35 mm., of male 0.82 mm.

Remarks.—I regard it as beyond all doubt that the above-described form
is that originally recorded by Claus under the name Oithona spinirostris. It has
generally been confounded with the very nearly allied species described by Baird
as O. plumifera, from which, however, it is at once distinguished by the absence
of the very conspicuous brightly-coloured plumes projecting in the latter at each
side of the trunk, and from which indeed the specific name plumifera has been
derived. These plumes in reality belong to the natatory legs, and are formed
by the sete attached outside the 2nd basal joint of the legs, which in the said
species are richly plumose, whereas in the form here under consideration they
ars simple and do not even project laterally. In addition to this distinguishing
character, Mr. Farran has recently pointed out some minute differences in the
structure of the oral parts between these two forms, which accordingly must be
regarded as distinct, though closely-allied species. Mr. Farran has proposed a
new specific name for the present species, viz., atlantica, but I think that his
doubt about the identity of Claus’ species with the one here under question cannot
properly be approved.

Occurrence.—I have observed this form in many different places on the
Norwegian coast, at least up to the Trondhjem Fjord. It is, however, not nearly
so common as the next species, and seems more properly to be an inhabitant of
the open sea, from which it is only occasionally brought in by the currents to
the shores and fjords.

When kept living in a vessel with fresh sea-water, the specimens are
always found freely suspended in the water, more generally in an erect attitude,
with the anterior antenne and the caudal sete spread to each side, these parts
apparently serving as a very effective balancing apparatus. In this attitude the
animal often rests for long time nearly immobile, only now and then, by
the action of the natatory legs, making a short bound to change its place. To
judge from the structure of the oral parts, the animal must be of a very rapacious
nature, probably feeding upon other small pelagic animals. These may at
first be seized by the slender maxillipeds and by them thrown in against the

other oral parts, the structure of which indeed seems to be more adapted for
killing than for masticating the prey.

Distribution.—As this form has generally been confounded with O. plumi-
fera, its true distribution is as yet rather difficult to determine. In all probability
it has a similar wide range in the Oceans to that of the next species. With
full certainty it may be said to be distributed all over the North Atlantic, as
also in the Mediterranean.

2. Qithona helgolandica, Claus.
(Pl. IID).
Oithona helgolandica, Claus, Die freilebenden Copepoden, p. 105, Pl. XI, figs, 10—12.
Syn: Oithona spinifrons, Boeck.

: pygmed, Boeck.
s similis, Claus.
rn spinirostris, Giesbrecht (not Claus).

Specific Characters.— Female. Body of the usual slender form, though
somewhat less so than in the preceding species. Rostrum, as in that species,
acutely pointed, but abruptly bent downwards at a right angle to the axis of
the body, so as not to be visible in the dorsal aspect of the animal. Genital
segment somewhat less dilated in its anterior part. Caudal rami not nearly
attaining the length of the anal segment, and less divergent than in O. spinirostris,
seta of outer edge shorter. Anterior antenne, when reflexed, extending scarcely
beyond the anterior division of the body, and composed of about 10 joints, some
of which, however, are only faintly defined. Posterior antennz and oral parts
agreeing in structure witb those in the preceding species. Natatory legs, how-
ever, exhibiting some characteristic differences: 1st pair with the outer ramus
armed in a manner similar to that in O. spinirostris, except that the apical spine
is less strong and almost setiform; inner ramus apparently only biarticulate, the
2 outer joints being confluent. 2nd and 3rd pairs with no spine outside the middle
joint of the outer ramus, though exhibiting at the end of the joint a small
dentiform projection of the margin. 4th pair without any spines either on the
Ist or 2nd joints. Terminal joint of this ramus in all 3 pairs with only a single
small spine outside, attached close to the end, and exhibiting moreover in the
2nd and 3rd pairs a very small dentiform prominence of the margin at about the
middle of the joint. Ovisacs narrow oblong and closely appressed to the sides of
the tail, each sac containing only a single series of very large and pellucid ova.

Male closely resembling that of the preceding species, but of smaller size,
and moreover differing somewhat in the armature of the natatory legs, the ter-

minal joint of the outer ramus having only 2 spines outside.

Body in both sexes extremely pellucid, without any obvious pigment.

Length of adult female 0.70—0.90 mm.; of male 0.50-—0.60 mm.

Remarks.—There cannot in my opinion be any doubt, that the form at
first recorded by Claus as O. helgolandica is the present species. It has subse-
quently been redescribed by the same author from Mediterranean specimens, but
under another specific name, viz., similis, and this name has been applied to the
present species by most authors. According to the rules of priority, however,
the first name under which a species has been recorded should in every case be
retained. The 2 forms named by Boeck O. spinifrons and O. pygmea are un-
doubtedly both referable to the present species, and this is also the case with
the form described by Dr. Giesbrecht from the bay of Kiel as O. spinirostris.
The present species is easily distinguishable from the preceding one by the rather
different form of the rostrum, the less elongated anterior antennz, and the very
different manner in which the ovisacs are borne by the female. Also in the struc-
ture of the natatory legs some well-marked differences are found to exist, as
shown in the above diagnosis.

Occurrence.—This form occurs very abundantly along the whole coast of
Norway, both on the outer shores and in the fjords. In the Christiania Fjord
I have often taken it in great numbers even close to the beach of the innermost
shallow creeks. As with the preceding species, male specimens are much scarcer
than females, and seem only to appear in certain seasons.

Distribution.—The distribution of this species seems to be very extensive.
It has been noted as far north as in Mosel Bay, Spitsbergen, and southwards
in the Mediterranean, off the Canary Islands, and even in the Indian Ocean. I have
myself examined specimens taken off the coast of New Zealand, and have care-
fully compared them with northern specimens, without having been able to

detect any difference whatever.

Fam. 2. Cyclopinide.

Characters.—Body of somewhat varying shape, but never so slender as
in the Oithonide, the anterior division being, as a rule, considerably dilated.
Head in most cases confluent with the 1st trunk-segment; rostral projection short
and generally bent in against the ventral face. Anterior antenne less elongated
than in the Oithonidz, tapered, and clothed with moderately long sete; those in

male strongly hinged. Posterior antenne generally composed of 4 joints. Oral

2 — Crustacea.

10

parts well developed and on the whole built on the same type as in the Calanoida.
Natatory legs comparatively short and stout, with both rami 3-articulate and
subequal in length. Last pair of legs generally extended laterally and composed
of 1—3 joints.

Remarks.—The type of this family is the genus Cyclopina of Claus, which
has generally been considered as closely allied to Cyclops, but which in reality
differs very essentially in the structure of the oral parts, which much more
resembles that found in the Calanoida. 4 different genera referable to this

family will be described in the sequel.

Gen. 2. Cyclopina, Claus 1863.

Generic Characters—General form of body much resembling that in
the genus Cyclops. Anterior antenne more or less elongated and composed
of a somewhat varying number of articulations; posterior antenne distinctly 4-
articulate. Mandibles with the cutting edge divided into a number of sharp claw-
like denticles, palp comparatively large, biramous, inner ramus well developed,
biarticulate, outer generally multiarticulate. Maxille with the masticatory lobe
well defined and armed with several claw-like spines, palp lamellar, with both
outer appendages sharply defined and carrying long plumose sete. Anterior
maxillipeds rather stout, with the 2nd basal joint clawed, and the terminal part
well developed, consisting of 3 joints. Posterior maxillipeds more slender, with
the terminal part generally divided into 3 or 4 setiferous joints. Natatory legs
of normal structure. Last pair of legs extended laterally, and composed of 2 or
3 joints, none of which are lamellar.

Remarks.—This genus was established in the year 1863 by Claus, to
include a species, C. gracilis, found by him at Messina. The genus is chiefly
characterised by the Cyclops-lke form of the body, and by the very full devel-
opment of the mandibular and maxillary palps, which strongly recalls that
in the Calanoida. Several species have been recorded by different authors; but
some of these have turned out to be referable to other genera, not even belonging
to the present family. In the succeeding pages 4 different species of this genus,
belonging to the fauna of Norway, will be described, and I am much disposed to
believe that their number will be considerably increased by a closer study of our
Copepod-fauna. For instance, many years ago, off the Lofoten islands, I observed
2 peculiar forms, the one distinguished by the excessive prolongation of the

itl

caudal rami, the other by the strong development of the spines on the legs.
The specimens of these 2 forms, which I had noted with the provisory names,
C. longifurca and C. ewacantha, have, however, unfortunately been Jost, and I am
thus unable to give any closer description of them here. A small species of this
genus has also been described by me from the Chatham Islands under the name
of C. pusilia, and another species has recently been recorded by Th. Scott as
C. longicaudata.

3. Cyclopina gracilis, Claus.
(inv):
Cyclopina gracilis, Claus, Die freilebenden Copepoden, p. 104, Pl. X, figs. 9—15.

Syn: Cyclopina norvegica, Boeck.
Cyclops salinus, Brady.

Specific Characters.—Female. Body moderately slender, with the anterior
division oval in form, greatest width exceeding half the length and occurring about
in the middle. Tail rather slender, with the genital segment about the length of
the other 3 combined and gradually narrowed behind. Caudal rami of somewhat
varying length, though scarcely longer than the last 2 segments combined, sub-
linear in form and only slightly diverging, seta of outer edge placed in front of
the middle; apical sete of moderate length, the inner medial one being, as usual,
the longest and about equal to the tail in length; seta of inner corner scarcely
longer than that of the outer. Anterior antenne not much elongated, being
considerably shorter than the cephalic segment, and composed of 10 joints, the
6th of which is much the longest and about equal in length to the 4 succeeding
ones combined. Posterior antennze with the last joint scarcely as long as the
2nd. Natatory legs with the spines outside the outer ramus of moderate size,
3 such spines being present on the terminal joint, except in 4th pair, where only
2 spines occur outside the apical spine. Last pair of legs biarticulate, proximal
joint comparatively broad and finely ciliated inside, carrying outside the usual
slender bristle, distal joint shorter and narrower than the proximal one, sub-
quadrangular in form, and armed on the obtusely truncated extremity with 2
somewhat unequal lanceolate spines, between which a slender bristle is attached.
Ovisacs of moderate size, oval in form, and carried closely appressed to the sides
of the tail.

Male of much smaller size than female, and easily distinguished by the
strongly hinged anterior antenne and the distinctly 5-articulate tail, the Ist
(genital) segment of which is considerably dilated. Last pair of legs of exactly
the same appearance as in the female.

12

Body in both sexes of a whitish grey colour, with a faint yellow tinge.

Length of adult female 0.43—0.57 mm.

Remarks.—This form was rather imperfectly described by Claus from
Mediterranean specimens, and has subsequently been observed by other authors
in different places of the northern Ocean. The form recorded by Boeck as C.
norvegica can scarcely be regarded as specifically distinct, though it represents
a strictly littoral variety, with the caudal rami comparatively shorter than in the
typical form. Dr. Giesbrecht has also called attention to the variation in this
respect both in the present and next species. The Cyclops salinus of Brady is
unquestionably the present species, and belongs to its variety norvegica, Boeck.
The specific name gracilis proposed by Claus for the present species, is some-
what inappropriate, since in reality this species is of less slender form of body
than most of the other known species.

Occurrence.—l have taken this form in several places on the Norwegian
coast, from the Christiania Fjord at least up to the Trondhjem Fjord. It is a
strictly littoral form, being found close to the shore among algz and scarcely
ever, like the next species, at any considerable depth. The variety norvegica
occurs rather frequently in shallow creeks and in pools left by the tide, both on
the southern and western coasts.

Distribution.—British Isles (Brady), coast of France (Canu), bay of Kiel
(Giesbrecht), Franz Josef Land (Scott), Polar Islands north of Grinnel Land
(2nd Fram Expedition), Mediterranean (Claus), Black Sea (Czerniawsky).

4. Cyclopina longicornis, Boeck.
(Eee):
Cyclopina longicornis, Boeck, Nye Slegter og Arter af Saltvandscopepoder. Chr. Vid. Selsk.
Forhandl. 1872, p. 41.
Syn: Cyclopina littoralis, Brady.

Specific Characters.—Female. Body comparatively more slender than in
the preceding species, with the anterior division oblong oval in form, greatest
width about equalling half the length and occurring in the middle, cephalic segment
eradually tapered anteriorly, with the front narrowly rounded. Tail very slender,
almost equalling in length the anterior division, genital segment sligthly dilated in
front and shorter than the 3 succeeding segments combined. Caudal rami long
and narrow, being generally longer than the 2 preceding segments combined,
seta of outer edge rather slender and attached a little in front of the middle;
apical sete very unequal, the inner medial one equal to the whole tail in length
and fully twice as long as the outer, seta of outer corner scarcely half as long

13

as the inner. Anterior antenne much more elongated than in the preceding
species, about equalling in length the cephalic segment, and composed of 18 well
defined joints, 3rd joint much the largest, 6th joint exhibiting a shght indication
to be subdivided into 3 joints. Posterior antennz with the terminal joint fully
as long as the 2 preceding joints combined. Natatory legs with the seta attached
inside the Ist joint of the inner ramus remarkably strong, especially in the 2
posterior pairs; terminal joint of outer ramus in 4th pair with only a single
spine outside, the distal spine being replaced by a thin bristle abruptly bent
inwards. Last pair of legs of comparatively feeble structure, and composed each
of 3 joints, the first 2 somewhat lamellar and finely ciliated inside, middle joint
carrying outside the usual bristle, last joint comparatively small, and provided
with 4 slender ciliated sete, the innermost of which is the shortest. Ovisacs of
moderate size and slightly divergent.

Male, as usual, smaller than female, and easily recognizable by the strongly
hinged anterior antenne. Last pair of legs differing from those in female in
being 4-articulate, the last joint being subdivided into 2 well defined joints, the
proximal of which carries on each side a seta, whereas the distal joint has 4
sete on the tip.

Body semipellucid, with scattered opaque patches of a whitish or yellow
colour, in some cases, moreover, exhibiting a fine rosy tinge on several parts of
the body, as also partly on the anterior antenne.

Length of adult female 0.70—0.90 mm.

Remarks.—This form has generally been recorded under the specific
name littoralis proposed by Brady. As, however, the name longicornis, assigned
to this species by Boeck, dates from the very same year, and is a much more
adequate name, I have found it suitable to prefer that name to the one proposed by
Brady. For the present species cannot in reality be said to be, like the preceding
one, a strictly littoral form, as it more generally occurs in greater depths and
is only quite occasionally met with in the littoral region. I have found that
such specimens are of smaller size and have the caudal rami less elongated than
in the typical form, thus more properly constituting a particular variety, for
which the name lftoralis may be retained.

The present species is easily distinguished from the preceding one by the
more slender form of the body, the much more elongated anterior antennx, and
the somewhat different shape of the caudal rami. In the structural details also
some well-marked differences are found, especially as regards the structure of the
last pair of legs.

Occurrence.—I have found this form rather frequently in many places of

14

the Norwegian coast, from the Christiania Fjord at least up to the Trondhjem
Fjord. It is generally met with in depths ranging from 10 to 60 fathoms, espe-
cially where the bottom consists of coarse sand; much more seldom it is found
in shallower water among alge. Like the other species of the present genus, it
is a true bottom-form, keeping constantly close to the ground. When disturbed,
it darts away with great rapidity, to settle again very soon in another place.
I have never seen it moving freely for any length of time in the water.
Distribution.— British Isles (Brady), Cuxhaven (Timm), Mediterranean
(Giesbrecht), Polar Islands north of Grinnel Land (2nd Fram Exped.).

5. Cyclopina brevifurea, G. O. Sars, n. sp.
(Pl. VI).

Specific Characters.—Female. Body moderately slender, with the anterior
division oblong oval in form, greatest width scarcely exceeding half the length,
front evenly rounded. ‘Tail not attaining half the length of the anterior division,
genital segment comparatively large, being fully as long as the 3 succeeding seg-
ments combined, anal segment shorter than the preceding one. Caudal rami very
small, being scarcely longer than they are broad, seta of outer edge slender and
attached about in the middle, apical sete rather elongated, the inner medial
one considerably exceeding the length of the tail and, like the outer, clothed in
its proximal part with coarse distant hairs, seta of outer corner unusually slender,
being fully as long as that of the inner corner. Anterior antenne comparatively
longer and more slender than in C. gracilis, though not quite attaining the length
of the cephalic segment, and composed of 12 well-defined joints, the 6th of which
is much the largest, the 6 outer joints short and all of equal size. Posterior
antenne with the terminal joint about the length of the antipenultimate one.
Natatory legs about as in C. gracilis. Last pair of legs, as in that species, bi-
articulate, distal joint, however, comparatively larger, exceeding in length the
proximal one, and narrow oblong in form, inner edge finely ciliated, tip armed
with 2 slender and somewhat unequal spines, having between them a slender
bristle. Ovisacs of moderate size, oval in form, and borne closely appressed to
the sides of the tail.

Body rather pellucid, of a whitish gray colour, with light bluish trans-
parent ovaria.

Length of adult female 0 60—0.70 mm.

Remarks.—This form is closely allied to C. gracilis Claus, but differs
conspicuously in the shape of the anterior division of the body, the more slender

15

and distinctly 12-articulate anterior antenne, and the remarkably short caudal
rami, which latter character has given rise to the specific name here proposed.

Occurrence.—I have met with this form in several distant places on the
Norwegian coast, for instance at Risor on the southern coast, at Skutesnes on
the south-western coast, and at Bejan outside the Trondhjem Fjord. A single
well-marked ovigerous specimen was found, moreover, in a sample taken by Mr.
“Nordgaard in the Porsanger Fjord, Finmark. The specimens observed by me

were taken in depths ranging from 10 to 30 fathoms, muddy bottom.

6. Cyclopina elegans, Scott.
(Pl. VIL).

Cyclopina elegans, Th. Scott, Addition to the Fauna of the Firth of Forth. 12th Ann, Report of
the Fishery Board of Scotland. Part. III, p. 237, Pl. V, figs. 9—19.

Specific Characters.— Female. Body very slender, with the anterior division
narrow oblong in form, greatest width not attaining half the length and occurring
in its anterior part, front evenly rounded. Tail almost as long as the anterior
division and having the genital segment unusually large and tumid, clothed on
each side with small spikes; anal segment fully as long as the preceding one.
Caudal rami long and slender, equalling in length the last 2 segments combined;
outer edge with 2 successive bristles, the smaller one occurring at a short distance
form the base, the other attached nearer to the end and somewhat dorsally ;
apical sete of moderate length, that of the outer corner shorter than that of the
inner. Anterior antennse moderately slender, though not attaining the length of
the cephalic segment, and composed of 18 joints, the 4th and 5th joints exhibiting,
however, a more or less distinct sub-division, so that the number of joints may
be increased to 20—21. Posterior antennee with the terminal joint scarcely longer
than the antipenultimate one. Mandibular palp comparatively more slender than
in the other species, with the outer ramus shorter. Posterior maxillipeds with
the terminal part composed of 5 well-defined joints. Ist pair of legs, like the 3
succeeding ones, provided with 2 sets inside the middle joint of the inner ramus,
these setze being in 4th pair very coarse, almost spiniform. Last pair of legs
distinctly 3-articulate, Ist joint with a coarse ciliated seta inside, middle joint
rather dilated and carrying outside the usual slender bristle; terminal joint nar-
row oblong in form, exceeding in length the other 2 combined, and provided
outside with 2 sete, at the tip with another very slender seta and a stout spine.
Ovisacs of moderate size and somewhat divergent.

Colour whitish grey, with a slight yellow tinge.

Length of adult female about 0.80 mm.

Remarks,—This is a very distinct species, easily recognisable both by
the general form of the body and by the structure of some of the appendages.

Occurrence.—The only place where I have observed this species, is at
Farsund, south coast of Norway. It occurred here occasionally together with
C. longicornis in a depth of about 20 fathoms, sandy bottom.

Distribution.— Firth of Forth (Scott), Gulf of Naples (Giesbrecht).

Gen. 3. Cyclopinella, GeO) Sars, i

Generic Characters—General appearance resembling that in the genus
Cyclopina, the anterior division of the body being considerably dilated, the posterior
narrow and attenuated. Head defined from the Ist pedigerous segment by a
well-marked suture. Anterior antennee comparatively short and composed of a
limited number of articulations. Posterior antenne with the first joint simple and
quite smooth. Mandibles short and stout, with the palp less fully developed than
in Cyclopina, being simple, without any outer ramus. Maxille likewise rather
short, palp with the 2 outer appendages well developed and of about equal size,
one of the apical spines, as also those of the masticatory lobe, unusually thick,
almost digitiform. Anterior maxillipeds rather compact, with the claw of the
2nd basal joint scarcely different from the spines of the terminal part. Posterior
maxillipeds much smaller, and of the usual structure. Natatory legs well developed
differing somewhat in structure from those in Cyclopina. Last pair of legs less
rudimentary than usual, being distinctly 3-articulate, with the terminal joint
comparatively large and armed with strong lanceolate spines.

Remarks.—This new genus is somewhat allied to Cyclopina, though dis-
tinguished by certain apparently fundamental differences, of which may be named
the distinct separation of the head from the Ist pedigerous segment, and the
simple structure of the mandibular palp. Only a single species of this genus

has hitherto come under my notice.

7. Cyclopinella tumidula, G. O. Sars, n. sp.
(Pl. VIII).

Specific Characters.—Female. Body comparatively short, with the anterior
division greatly tumefied and almost pyriform in shape, the greatest width occurring

17

far in front and considerably exceeding half the length. Tail very narrow and
tapered, with the genital segment only slightly dilated, anal segment fully as long
as the preceding one. Caudal rami somewhat exceeding in length the anal seg-
ment and narrow linear in form, seta of outer edge attached about in the middle,
apical sete rather unequal, the inner medial one, as usual much the longest and
about equalling in length the tail; seta of outer corner quite rudimentary, that of inner
attaining the length of the corresponding ramus and very thin. Eye wholly absent.
Anterior antenne much shorter than the head, and composed of 12 well-defined
joints, the 9th of which is somewhat longer than the others and carries a slender
sensory filament. Posterior antenne with the terminal joint unusually short, not
even attaining the length of the preceding one. Mandibular palp forming a simple
bi-articulate stem, the distal joint of which is very small and provided with 3
curved sete. Natatory legs with no seta inside the Ist joint of the outer ramus;
Ist pair with a strong spine outside the terminal joint of the inner ramus, re-
placing the usual seta; spines of outer ramus in this and the succeeding pairs
slender, and edged with hyaline rims, 4 such spines being present on the terminal
joint in the 3 anterior pairs, 3 in that of the 4th pair, inner ramus of the latter
pair unusually narrow and, like that of the 2 preceding pairs, armed at the tip
with 2 spines. Last pair of legs with the Ist joint quite unarmed, 2nd carrying
outside a slender bristle, terminal joint much longer than the other 2 combined,
oblong quadrangular in form, and much constricted at the base, carrying outside,
somewhat in front of the middle, a strong lanceolate spine and at the transversely
truncated end 2 similar spines and a very small bristle between them, inner edge
of the joint straight and finely ciliated. Ovisacs small, and borne closely appressed
to the sides of the tail, each containing, as a rule, only 3 ova arranged in a
single row.

Male exhibiting the usual sexual characters. Last pair of legs of exactly
the same appearance as in female.

Body of the usual whitish grey colour, but appearing darker on account
of the translucent, very capacious anterior part of the intestine, which is generally
filled with dark brown contents. A peculiar opaque body of a whitish or pale
orange hue, and transversely oval or semilunar in form, is constantly found im-
mediately inside the dorsal wall of the head, in front of the intestine, and is
very conspicuous in the living animal.')

Length of adult female 0.68—0.75 mm.

1) T am unable to say anything about the significance of this body. It cannot be the
missing visual organ, as it does not occupy the usual place of the eye, being far remote from
the front. As to structure, it seems to consist of a uniform granular matter.

3 — Crustacea.

18

Remarks.—In its general appearance this form is rather similar to
certain species of the genus Cyclopina, and I was indeed at first inclined to refer
it to that genus. The closer anatomical examination has, however, proved it to

be in reality so different, that in my opinion it ought to be generically separated.

Occurrence.—I have met with this peculiar form in several distant places
on the Norwegian coast, for instance at Risogr and Lillesand on the southern
coast, at Christiansund on the western coast, and in the Trondhjem Fjord. In
all places it occurred on a muddy bottom, partly covered by decaying alge, the

depth ranging from 20 to 40 fathoms.

Gen. 4. Cyclopetta, G. O. Sars, n.

Generic Characters.—Body somewhat depressed, with the 2 chief divisions
less sharply marked off from each other than in the 2 preceding genera. Head
confluent with the Ist pedigerous segment, and conspicuously contracted in front.
Tail comparatively short. Anterior antenne of inconsiderable length, with the
number of articulations reduced. Posterior antenne likewise unusually short and
stout, and clothed with strong plumose sets. Mandibles with the palp distinctly
biramous, outer ramus well developed, inner uniarticulate. Maxille and maxilli-
peds very small and difficult to examine, though apparently built on the same
type as in the other Cyclopinide. Natatory legs well developed and of normal
structure. Last pair of legs consisting each of a single lamellar joint edged
with ciliated sete.

Remarks.—This new genus in some respects differs rather conspicuously
from the 2 preceding ones, and seems to exhibit a certain approach to the next
anomalous genus, Pterinopsyllus, though it is distinguished also from this genus
by several well-marked characters. The genus is only founded upon a single
species, to be described below.

8. Cyclopetta difficilis, G. O. Sars, n. sp.
(PI. IX).

Specific Characters.—Female. Body comparatively short and _ stout,
and distinctly depressed, with the anterior division oblong fusiform in outline,
greatest width scarcely exceeding half the length, and occurring about in the
middle. Cephalic segment rather large and evenly contracted anteriorly, with

19

the front narrowly rounded. Tail not attaining half the length of the anterior
division, and scarcely tapering behind; genital segment conspicuously constricted
in the middle, anal segment equalling in length the 2 preceding ones combined.
Caudal rami short, not nearly attaining the length of the anal segment, and
quadrangular in shape, seta of outer edge attached about in the middle, apical
setze of moderate length, the inner medial one about twice as long as the outer,
both coarsely ciliated, seta of outer corner much smaller than that of the inner.
Anterior antenne scarcely exceeding half the length of the cephalic segment, and
each composed of only 9 joints clothed with strong partly ciliated sete; 5th joint
the longest, 6th about the length of the 3 outer joints combined. Posterior antenne
distinctly 4-articulate, Ist joint provided at the end on either side with a strong
ciliated seta, 2nd joint with a similar seta in front, 3rd joint with 4 such sete
outside, last joint about the length of the 2 preceding ones combined, and car-
rying on the tip 6 anteriorly-curving and likewise densely ciliated sete. Man-
dibular palp with the outer ramus composed of 4 well defined joints, inner ramus
with 3 comparatively short apical sete. Proximal outer lobe of the maxillary
palp much larger than the distal one and carrying 4 unusually thick plumose
sete. Maxillipeds very small and densely crowded, the anterior ones apparently
of normal structure, the posterior ones with the number of the terminal joints
much reduced. Natatory legs not exhibiting any pronounced peculiarity in their
structure. Last pair of legs consisting each of a rounded oval lamella attached
outside the last trunk-segment and provided with 3 thick and curved ciliated sete;
just above this lamella a thin bristle is attached to a conical projection of the
segment itself.

Colour not yet ascertained.

Length of adult female 0.60 mm. .

Remarks.—The present form cannot be confounded with any of the other
Cyclopinide, exhibiting, as it does, a most characteristic appearance, somewhat
recalling that found in certain of the semi-parasitic forms, to which, indeed, I was
at first inclined to refer it, before having made out its anatomy.

Occurrence.—Only 3 specimens of this remarkable form, all of the female
sex, have hitherto come under my notice. They were picked up from a sample
taken last summer at Risgr, south coast of Norway, in a depth of about 40
fathoms, muddy sand. All 3 specimens have been sacrified for dissection, in
order to get a satisfactory conception of the structure of the very small and
densely crowded oral parts. The specific name here proposed alludes to the
difficulty experienced in the examination of these parts.

20

Gen, 5. Pterinopsyllus, Brady, 1880.

Syn: Lophophorus, Brady (not Temminch).
Cyclopella, Claus.

Generic Characters.—Body robust and somewhat depressed, with the
anterior division moderately dilated, the posterior less narrow than usual. Head
coalesced with the Ist pedigerous segment, and terminating in a blunt rostrum
projecting downwards. Caudal rami short, with the 2 middle apical sete very
strong and densely ciliated. Anterior antenne short and stout, with the number
of articulations reduced, and clothed with unusually strong pennate sete; those
of male of much larger size and strongly hinged. Posterior antennz likewise
short, and only 3-articulate, the last 2 joints being united. Mandibles with the
cutting part considerably expanded and coarsely dentate; palp comparatively
slender, with the outer ramus small and undivided, inner ramus biarticulate.
Maxille with all the constituting parts well developed. Anterior maxillipeds very
stout, with 3 well-defined terminal joints armed with strong spines. Posterior
maxillipeds with the terminal part very fully developed and composed of 5 joints,
the 1st much larger than the others. Natatory legs strongly built, with short
‘and blunt spines outside the outer ramus; inner ramus of Ist pair in male pre-
hensile, that of 4th pair more or less reduced in female, normal in male. Last
pair of legs comparatively small and not extended laterally, being composed of
3 more or less lamellar joints, somewhat different in the two sexes.

Remarks.—This genus was established in the year 1878 by Prof. Brady,
to comprise a peculiar Copepod found by him off the British coast. As, however,
the generic name he proposed, Lophophorus, had been preoccupied for a genus
of birds, he changed it in the year 1880 to Pterinopsyllus. The name Cyclopella
proposed by Claus is of later date, and must yield to that given to the genus
by Brady.

The systematic position of the present genus has remained somewhat
doubtful. In some respects it recalls certain genera among the Harpacticoida,
and, indeed, it has been placed within that group in the list of Crustacea from
Northumberland and Durham published by Norman and Brady. I think, however,
that its place within the group Cyclopoida cannot at present be disputed. On
the other hand, owing to the peculiarities observed in this genus, it might be
thought necessary to establish for its reception a distinct family, Pterinopsyllide.
Indeed, I was at first much inclined to do so; but after having become acquainted

with the preceding genus, Cyclopetta, which in some respects exhibits an evident

21

approach to the one here under consideration, I find that, without any serious
scruple, it may be included in the family Cyclopinidew, as here defined.

In addition to the typical species described below, 2 closely-allied species,
P. egregius and P. illustris, have been recorded by Dr. Giesbrecht from the
gulf of Naples.

9. Pterinopsyllus insignis, Brady.
(Pl. X & XI).
Lophophorus insignis, Brady, Monograph of British Copepoda, Vol. I, p. 122, Pl. XII, figs. 1—10,
Pl. XV, fig. 10.

Specific Characters.— Female. Body rather stout, with the anterior division
ovate in outline, greatest width exceeding half the length and occurring about in
the middle. Cephalic segment large and narrowly produced in front. Last
trunk-segment sharply defined from the preceding one, and projecting laterally
in a small dentiform process. Tail about half the length of the anterior division,
and nearly of uniform width throughout; genital segment about as long as the 3
succeeding ones combined, and scarcely at all dilated in front; anal segment
shorter than the preceding one. Caudal rami quadrangular in shape, being scarcely
Jonger than they are broad, seta of outer edge obsolete, the 2 middle apical sete
very strong and divergent, with coarser and more scattered hairs on their proximal
parts, seta of outer corner much smaller than that of the inner, both very thin
and naked. Anterior antenne scarcely more than half as long as the cephalic
segment and rather broad at the base, being composed of 8 joints, the 2nd of
which is the largest, 5th joint very small. Posterior antenne clothed along the
outer edge and at the tip with coarsely hairy sete, inner edge without any sete.
4th pair of natatory legs with the inner ramus much shorter than the outer,
middle joint imperfectly defined from the terminal one and without any sete
inside, the latter joint having inside 2 short blunt spines replacing the usual
sete. Last pair of legs with the Ist joint imperfectly defined at the base, but
carrying inside a well-developed ciliated seta, 2nd joint conically produced out-
side and carrying the usual thin bristle, last joint much larger than the other 2
combined, and forming a rounded oval lamella coarsely ciliated inside and provided
with 4 slender sete, 3 of which are ciliated, the 4th, issuing from the tip, very
thin and smooth. Ovisacs, according to Brady, short pyriform, with a limited
number of ova.

Male of smaller size than. female, and easily recognisable by the very
coarse structure of the anterior antenne, which are powerful prehensile organs

divided into 12 joints. Inner ramus of Ist pair of legs with the apical spine

ee

peculiarly transformed, being abruptly bent, so as to form a claw-like prehensile
appendage. Inner ramus of 4th pair of quite normal structure. Last pair of
legs as in the female, 3-articulate; the 1st joint does not, however, answer to
the Ist joint in the female, but to the 2nd, as is clearly shown by the bristle
issuing from its outer side. Of the other 2 joints, which accordingly answer to
the terminal joint in the female, the proximal one is much the larger and carries
at the end on each side a seta, whereas the distal joint is quite short with 4
diverging sete on the end.

Body in both sexes of a whitish grey colour, with a slight violaceous
tinge. Eye in living specimens very conspicuous and of light red colour.

Remarks.—The present form may be easily recognised from any of our
indigenous Cyclopoida, both by its characteristic outward appearance and by the
rich ornament of coarsely-ciliated sete, which clothes most of the appendages.
Especially are these sete very conspicuous on the anterior antenne, where they
partly assume a pennate or pectinate character, giving these appendages a peculiar
shruppy appearance. It was indeed to this peculiarity that the generic name,
Lophophorus, at first proposed by Brady, alluded. From the 2 Mediterranean
species recorded by Dr. Giesbrecht the present form cannot be distinguished
without a very close anatomical examination.

Occurrence.—I have met with this pretty form occasionally in 3 different
places on the Norwegian coast, viz., in the inner part of the Christiania Fjord,
at Risor, and at Flekkerg, outside Christiansand. The specimens were taken in
depths ranging from 20 to 40 fathoms, muddy sand. Canon Norman has taken
this form also in the Trondhjem Fjord, at Rodberget, where it occurred in the
considerable depth of 150 fathoms.

Distribution.—Coast of England and Scotland (Brady, Scott), Gulf of
Naples (Giesbrecht). |

Fam. 3. Cyclopide.

Characters.—General form of the body resembling that in the typical
Cyclopinide, the anterior division being more or less dilated, the posterior much
narrower and attenuated. Head in all the known forms confluent with the Ist
pedigerous_ segment, and having the rostrum bent in against the ventral face.
Anterior antenne more or less elongated and strongly hinged in male. Posterior

antenne generally 4-articulate, with an elongated seta at the end of the Ist joint

23

posteriorly. Anterior lip with the terminal edge finely denticulate. Mandibles
with the palp quite rudimentary, being reduced to a small knob-like process
carrying 2 or 3 ciliated sete, Maxille with the palp likewise imperfectly devel-
oped and without any distinctly-defined outer appendages. Maxillipeds built on
the same type as in the Cyclopinide, but of comparatively simpler structure.
Natatory legs, as a rule, well developed, with subequal triarticulate rami, though
in some instances the number of joints in the rami may be reduced. Last pair
of legs generally small and of the same appearance in the two sexes,

Remarks.—This family, in the restriction here adopted, is chiefly distin-
guished from the 2 preceding ones by the rudimentary condition of both the
mandibular and the maxillary palps. This character is invariably found in all
the forms, and must be regarded as of fundamental significance. In other respects
this family exhibits a close resemblance to the Cyclopinide.

Only a limited number of species, belonging to 2 genera, are strictly
marine, whereas in fresh water we find a great number of forms, all generally
referred to a single genus, viz., Cyclops. I have, however, found it appropriate
to divide this extensive genus into a number of closely-allied genera (or sub-

genera), which will be characterised in the next parts of the present Volume.

Gen. 10. HKuryte, Philippi, 1843.

Syn: Thorellia, Boeck.

Generic Characters.— Body, as a rule, rather robust, the anterior division
being considerably tumefied, and sharply marked off from the slender and attenuated
tail. Anterior antenne in female divided into a great number of short, but well-
defined joints; those in male much more strongly built, and hinged in the usual
manner. Posterior antenne rather stout, 4-articulate, with the last 2 joints
comparatively short. Mandibles with the cutting edge divided into several sharp
claw-like teeth, sete on the rudimentary palp not much elongated. Maxillee with
the masticatory lobe well developed and armed with strong dentiform spines,
palp forming an oblong lamella projecting beyond the masticatory lobe and
terminating in a serrated edge, being moreover provided on each side with 2
juxtaposed sete. Anterior maxillipeds rather stout, with the digitiform lobe,
issuing from the end of the Ist basal joint anteriorly, comparatively strong and,

like the 2nd basal joint, projecting in a claw-like spine accompanied by a much

24

thinner seta; terminal part composed of only a single joint armed with short
curved spines. Posterior maxillipeds of a somewhat unusual appearance and
apparently sub-prehensile, the terminal part being abruptly bent and terminating
in 2 short claw-like spines. Natatory legs powerfully developed with broad flattened
basal part and the joints of the rami partly conspicuously expanded; spines of
outer ramus lanceolate, bordered by broad hyaline rims finely serrated at the
edges; several of the sete, both of this and the inner ramus, transformed to
similar, though more delicate spines. Last pair of legs less rudimentary than
usual, and resembling in structure those in the genus Cyclopinella.
Remarks.—This genus was established by Philippi as early as in the
year 1843, but was not recognised by Boeck, who records it under another name,
viz., Thorellia. The genus is especially characterised by the peculiar structure
of the maxillary palp and that of the posterior maxillipeds, as also by the trans-
formation of several of the natatory sete on the legs to lanceolate spines. Two
species of this genus have hitherto been described, both occurring off the Nor-
wegian coast, and a 3rd new species is here added. All 3 species are exclusively

marine. :

10. Euryte longicauda, Philippi.
(Pl. XII).

Euryte longicauda, Philippi, Fernere Beobachtungen iiber die Copepoden des Mittelmeeres. Arch.
f. Naturg. 1843, p. 63, Pl. 3, fig. a—d.

Syn: Thorellia brunnea, Boeck.
Cyclops, nigricauda, Norman.
Cyclopina Clausi, Czerniawsky.

Specific Characters.—Female. Anterior division of body rounded oval in
outline, greatest width almost equalling ?/; of the length, and occurring somewhat
behind the middle. Cephalic seginent very large, considerably longer than all
the free trunk-segments combined, and evenly rounded in front. Last trunk-
segment somewhat produced on each side. ‘ail very slender, almost attaining
the length of the anterior division; genital segment imperfectly subdivided in the
middle, and exhibiting on each side a dentiform posteriorly-pointing projection;
anal segment longer than the preceding one. Caudal rami very slender and
elongated, equalling in length the last 3 segments combined, and sublinear in
form, diverging a little in their distal parts, which appear slightly thickened;
seta of outer edge attached near the extremity; apical sete not much elongated,
the inner medial one not nearly attaining the length of the tail, that of the outer
corner shorter than that of the inner. Anterior antenne rather slender, though

ere

not quite attaining the length of the cephalic segment, and composed of 21 joints,
the 1st of which is much the largest; 2nd joint faintly subdivided in the middle.
Posterior antenne rather strongly built, 2nd joint angularly produced at the end
inside, and almost as long as the outer 2 joints combined, some of the apical
sete rather strong, almost spiniform. Ist pair of natatory legs with the inner
corner of the 2nd basal joint considerably produced and carrying a strong de-
flexed spine; middle joint of inner ramus very broad and, like that of the suc-
' ceeding pairs, provided inside with 2 sete, terminal joint with all the sete trans-
formed to spines. Setz of terminal joint of outer ramus in 2nd to 4th pairs
likewise transformed. Last pair of Jegs with the Ist joint very small and imper-
fectly defined at the base, 2nd joint likewise rather small, and carrying outside
the usual bristle, last joint comparatively large, oblong quadrangular in shape
and somewhat curved at the narrowed base, being armed with 3 strong lanceolate
spines, one of which issues a little beyond the middle of the outer edge, the
other 2 from the transversely truncated extremity; between the latter, moreover,
a thin bristle is attached. Ovisacs narrow oblong in form and greatly diverging.

Male, as usual, smaller than female and of somewhat more slender form
of body, being moreover easily recognised by the strongly hinged anterior antenne
and the distinctly 5-articulate tail.

Colour yellowish brown, with scattered patches of a darker hue; proximal
part of the caudal rami and the middle part of the anterior antennz generally
of a similar dark hue.

Length of adult female about 1.30 mm., that of male 0.90 mm.

Remarks.—The identity of the above-described form with Philippi’s Huryte
longicauda has been sufficiently proved by Dr. Giesbrecht, who observed the
species in about the same place, that Philippi had made his investigations in. The
name Thorellia brunnea, under which this species has been recorded by most
authors, is of much later date than: that given to this form by Philippi, and can-
not therefore be retained. It is also beyond doubt that both Cyclops nigricauda
Norman and Cyclopina Clausi Czerniawsky are referable to the same species.
From the 2 next species the present one may be easily distinguished by the very
long and slender caudal rami, as also by the manner in which the ovisacs are
borne in the female.

Occurrence.—I have found this form rather plentifully along the whole
Norwegian coast, from the Christiania Fjord to Vads@ in moderate depths among
alge. More particularly it seems to haunt places where the great Laminariz
grow, to the leaves of which it is often found clinging rather firmly, probably
by the aid of the clawed posterior maxillipeds, It moves through the water

4 — Crustacea.

26

in the usual jumping manner, and has on the whole in its behaviour much the
appearance of an ordinary Cyclops. Dr. Scott records a smaller form of this
species, which he designates as varietas minor. I have also myself in the inner
part of the Christiania Fjord observed such small, though fully adult specimens,
but have failed to detect any other differences from the typical form.
Distribution.— British Isles (Brady), coast of France (Canu), Gulf of Naples
(Philippi), Black Sea (Czerniawsky), eastern coast of Greenland (Buchholtz), Franz
Josef Land (Scott), Polar Islands north of Grinnel Land (2nd Fram Expedition). °

11. Euryte robusta, Giesbrecht.
(Pl. XIII).
Euryte robusta, Giesbrecht, Mittheilungen iiber Copepoden, 12—14, p. 58, Pl. 4, figs. 1—18.

Specific Characters.—Female. Body comparatively more robust than in
the preceding species, with the anterior division more regularly oval in outline.
Tail comparatively shorter and broader at the base; genital segment exhibiting
in the middle quite similar dentiform projections to those in EH. longicauda.
Caudal rami rather shorter than in that species, scarcely exceeding in length the
last 2 segments combined, and slightly diverging at the end; apical sete more
evenly ciliated, Anterior antenne, as in that species, rather slender and composed
of 20 joimts. Posterior antennze somewhat less robust, with the 2nd joint scarcely
angular behind and the apical sete thinner. Posterior maxillipeds with the apical
claws more slender and accompanied by 2 thin bristles. Structure of the legs
almost exactly as in A. longicauda, though having the spines comparatively shorter
and stouter. Ovisacs small and of irregularly rounded form, each containing a
very limited number of ova.

Male resembling that of the preceding species, but of somewhat more
robust form.

Body of a dark ochraceous colour, the caudal rami being tinged with
deep chestnut and the anterior antenne with bands of a similar hue.

Length of adult female 1.20—1.40 mm., of male about 1.00 mm.

Remarks.—1 cannot doubt that the above-described form is identical with
that recorded by Dr. Giesbrecht from the gulf of Naples, though there are a few
points of disagreement. Thus Dr. Giesbrecht counts 21 joints in the anterior
antenne, whereas I have never found more than 20 such joints, some of which
even are imperfectly defined. The figure given by him of the posterior antenne
also differs somewhat, and more agrees with those antenne in FE. longicauda.

Otherwise, however, the two forms seem to agree perfectly.

27

The present species is closely allied to E. longicauda, but is easily
distinguished by the comparatively more robust form of the body, and more
particularly by the considerably shorter caudal rami.

Occurrence.—I have found this form not unfrequently in several places of
the Norwegian coast, for instance at Kleven and Korshayn on the southern coast,
and at Aalesund and Christiansund on the western coast. It is a more pronounced
deep-water form than the preceding one, being generally found in depths ranging
from 20 to 60 fathoms, especially where the bottom consist of coarse sand inter-
mingled with mud. It is very perplexing, that this form has not yet been ob-
served off the British Isles, the Copepod-fauna of which has been so thoroughly
studied, especially by Th. Scott.

Distribution.— Gulf of Naples (Giesbrecht).

12. Euryte curticornis, G. O. Sars, n. sp.
(Pl. XIV).

Specific Characters.— Female. Body somewhat less robust than in the
preceding species, with the anterior division ovate in outline, the cephalic segment
being somewhat contracted in front. Last trunk-segment less produced laterally
than in the other 2 species. ‘ail exceeding somewhat half the length of the
anterior division, genital segment with only a slight rudiment of the lateral
denticles so conspicuous in the 2 preceding species. Caudal rami about equalling
in length the last 2 segments combined, and not at all diverging, tapering slightly
distally; apical sete of moderate length, the 2 middle ones clothed in their prox-
imal part with rather coarse and distant hairs. Anterior antenne much shorter
and thicker than in the 2 preceding species, though composed of a similar great
number of joints (20), most of the setz rather coarse and finely ciliated. Posterior
antenne of a similar structure to that in E. robusta. Posterior maxillipeds less
abruptly curved and having the terminal part much shorter, with the apical claws
extremely minute. Natatory legs built in the same manner as in the 2 preceding
species, though having the rami somewhat less broad and the spines more slender.
Last pair of legs likewise of a very similar structure, last joint, however, com-
paratively shorter. Ovisacs rather large, and borne closely appressed to the sides
of the tail.

Colour not yet ascertained.

Length of adult female 1.30 mm.

Remarks.—This new species may be at once distinguished from the 2
preceding ones by the much shorter an stouter anterior antenne, which character

28

indeed has given rise to the specific name here proposed. In the structural
detail also some minor differences are found to be present, especially as regards
the posterior maxillipeds and the caudal rami.

Occurrence.—Several specimens of this form were collected, many years
ago, at Skraaven, Lofoten islands. They occurred in a depth of about 6 fathoms,
on a sandy bottom partly overgrown with alge.

Gen. 11. Halicyelops, Norman, 1903.

Syn: Hemicyclops Claus (not Boeck).

Generic Characters.—Body of the usual cyclopoid shape, and somewhat
depressed in its anterior part. Head confluent with the Ist pedigerous segment,
and having the rostrum bent in against the ventral face. Anterior antenne short,
with the number of joints greatly reduced; those in male strongly hinged. Posterior
antenne with the outer 2 joints confluent. Mandibles with one of the cutting
teeth much larger than the others, sete of rudimentary palp comparatively short.
Maxillary palp forming a small lamella not extending beyond the masticatory
lobe, and terminating in a short spine accompanied by one or two sete. Anterior
maxillipeds with the digitiform lobe, issuing from the end of the 1st basal joint
anteriorly, rather small and terminating in 2 unequal sete. Posterior maxillipeds
imperfectly developed, being composed of 2 or 3 joints only. Natatory legs built
upon the usual cyclopoid type, but having the rami not nearly so broad as in
Euryte. last pair of legs with the proximal joint more or less completely
coalesced with the corresponding segment, distal jot broad lamelliform and
edged with partly ciated sete.

Remarks.—This genus was established in the year 1893 by Claus, to
include the form generally recorded as Cyclops ceqvoreus Fischer. As, however,
the name he proposed, Hemicyclops, had been preoccupied by Boeck, to designate
another very different genus, not even belonging to the same section, it has been
changed by Norman to Halicyclops. The genus is nearly allied to Cyclops, but
differs in the imperfect development of the posterior antenne and of the posterior
maxillipeds, as also in the peculiar structure of the last pair of legs. In addition
to the typical form, to be described below, another nearly-allied species has been
recorded by the present author from the Chatam islands as H. propmqvus, and

a 3rd species, not yet described, occurs, as a true planktonic form, in the Caspian

29

Sea. All the species are inhabitants of more or less brackish water, though they

may be of marine origin, as they are never found in purely fresh water.

13. Halicyclops magniceps (Lilljeborg).
(Pl. XV).
Cyclops magniceps, Lilljeborg. De crustaceis ex ordinibus tribus, ete, p. 204, Pl. XXII, fig. 1.
Syn: Cyclops ceqvoreus, Fischer.

- christianiensis, Boeck.

Specific Characters.—Female. Body moderately stout, with the anterior
division oblong oval in outline, greatest width about equalling half the length
and occurring somewhat in front of the middle. Cephalic segment very large
and broadly rounded in front; last trunk-segment only slightly produced laterally.
Tail scarcely more than half as long as the anterior division, genital segment
nearly of equal width throughout, anal segment shorter than the preceding one,
and deeply cleft at the end. Caudal rami about twice as long as they are broad
and somewhat divergent; seta of outer edge attached about in the middle; apical
sete rather slender, the inner medial one attaining half the length of the body;
seta of outer corner shorter than that of the inner. Anterior antenne compara-
tively short and stout, being composed of only 6 distinctly defined joints, the
first 2 rather dilated, the 3rd quite short, the 4th nearly as long as the outer
2 joints combined. Posterior antenne with the terminal joint sub-fusiform in
shape, and provided in the middle outside with a well-marked notch, indicating
the place where the 2 outer joints have been coalesced. Posterior maxillipeds
very small and only composed of 2 joints, the distal one much the smaller.
Natatory legs with the terminal joint of the inner ramus not much larger than
the middle one, and provided in the Ist pair with 2, in the other pairs with 3
spines in addition to the sete; terminal joint of outer ramus having 3 spines
outside in the 3 anterior pairs, 2 in the 4th pair. Last pair of legs with the
proximal joint imperfectly defined from the segment, distal joint much expanded,
spatulate in form, terminal edge obliquely truncated and carrying 4 comparatively
short sete, the innermost but one simple, the others ciliated. Ovisacs oblong
oval in form and borne closely appressed to the sides of the tail, each containing
only a limited number of ova.

Male much smaller than female, and having the anterior antenne very
strongly built, being composed of 11 more or less distinctly defined joints, the
last consituting the terminal section and produced in a sharp point. Last pair
of legs with the proximal joint more distinctly defined, distal joint only differing

ee!

from that in female by the presence of an additional seta attached inside the
others. .

Body semipellucid, of a whitish colour, with a very faint yellowish or
greenish tinge. QOvaria and ova in the ovisacs generally of a dark blue colour.

Length of adult female 0.75 mm.

Remarks.—This form was first recorded by Lilljeborg under the name
of Cyclops magniceps, but was rather imperfectly described, and, as moreover the
number of joints in the anterior antennz were erroneously indicated to 8, instead
of 6, the species was not recognised by subsequent authors, who generally recorded
it under the specific name e@qvoreuws proposed by Fischer several years afterwards.
The form named by Boeck Cyclop christianiensis is also unquestionably the same
species. It is distinguished from the nearly-allied form H. propingvus G. O. Sars
by the more produced caudal rami, as also by its larger size.

Occurrence.—I have found this form not unfrequently in the uppermost
part of the Christiania Fjord, where it occurs close to the border of the
shallow creeks in the immediate neighbourhood of the town. It also occurs
in other places, both of the south and west coasts of Norway, partly in more
or less brackish water.

Distribution.—Kullaberg, coast of Sweden (Lilljeborg), British Isles (Brady),
coast of France (Canu), Algeria (Richard), Madeira (Fischer).

Gen. 12. Cyclops, Miiller, 1776 (ex parte).

Generic Characters.—Anterior division of body moderately tumid, and
generally more tapered behind than in front; lateral parts of the 3 anterior trunk-
segments well defined and sub-angular behind; last trunk-segment more or less
produced laterally. Tail slender and attenuated, with the genital segment in
female more or less dilated in front. Anterior antenne of varying length, and
more generally composed of 17 well defined joints, though in some cases, by
concrescence, their number may be considerably reduced; those in male strongly
hinged, with the terminal section distinctly biarticulate. Posterior antennz with
all 4 joints well defined, the Ist carrying at the end posteriorly a long ciliated
seta. Rudimentary palp of the mandibles carrying 2 very long and densely
plumose sets accompanied by a short bristle. Maxillary palp scarcely extending
beyond the masticatory lobe, and provided outside near the base with 4 ciliated
setee, 3 of which issue from a slight expansion of the margin. Anterior maxilli-

as

peds moderately strong, with the Ist basal joint generally subdivided in the
middle, and provided anteriorly with a small rounded lobe carrying 2 plumose
sete; digitiform lobe issuing from the end of this joint anteriorly comparatively
small, with none of the sete unguiform. Posterior maxillipeds much more slender,
and composed of 4 well-defined joints. Natatory legs with both rami generally
3-articulate, though in some cases, by an imperfect separation of the 2 outer joints,
one or other of them, or all, may be only biarticulate; inner ramus of 4th pair with
2 apical spines. Last pair of legs very small and generally not extended laterally,
being composed of 2 joints, the proximal of which in some cases may be coalesced
with the corresponding segment, distal joint not expanded, and carrying a slender
apical seta and a short lateral spine. Seminal receptacle in female of compara-
tively simple structure, being generally transversely oval in shape.

Remarks.—This genus is here taken in a much more restricted sense
than done by other authors. Owing to the great number of species referred to
this genus, it has long appeared very desirable to group them according to their
mutual relationship, in order to get a clear survey on them. A such grouping
of the European species has indeed been effected by Dr. Schmeil in his very
valuable work on the fresh water Copepoda of Germany. I think, however that
we may be justified to take a further step, and to subdivide the old genus Cyclops
into a number of nearly-allied genera, each being designated by a particular
name. In the present work I have attempted to do so, distinguishing 5 different
genera, the name Cyclops being restricted to one of them, which comprises the
greater bulk of the hitherto known species. In this genus I have included 4 of
the 8 groups of Cyclopses distinguished by Dr. Schmeil, having not found sufficient
reason for a generic separation of these groups; the 4 other genera answer to
as many groups distinguished by Dr. Schmeil.

In the restriction here adopted, the present genus is, among other things,
characterised by the well defined and angular epimeral parts of the segments
composing the anterior division of the body, giving to the sides of that division
a more or less jagged appearance. Of the structural details, it is especially the
rudimentary last pair of legs which exhibits a very characteristic appearance,
conspicuously differing from that in any of the other 4 genera.

A considerable number of species referable to the present genus
will be described in the sequel, some of them being, however, so closely
allied, that their specific distinctness has not generally been recognised. They
all, like the species of the 4 succeeding genera, are exclusive inhabitants of
fresh water.

32

The diagnoses here given of the several species have chiefly been drawn up
from adult female specimens, the males affording, as a rule, no particular characters

availble for the specific distinction.

14. Cyclops strenuus, Fischer.
(Pl. XVI.

Cyclops strenuus, Fischer, Bulletin de la Societé Impér. d. Nat. de Moscow, Vol. XXIV, p 419
P]. IX, figs. 12—21.
Syn.!) ? Monoculus qvadricornis rubens, Jurine.
? Cyclops pictus, Koch.
3 qvadricornis, Lilljeborg.
brevicaudatus, Claus.
Clausi, Lubbock.

”

Specific Characters.— Female. Body moderately slender, with the anterior
division oblong oval in form, greatest width about equal to half the length and
occurring in the middle. Cephalic segment only slightly longer than the 4 suc-
ceeding segments combined, and narrowly rounded in front. Lateral parts of
penultimate trunk-segment terminating in a short tooth-lhke projection turned
somewhat outwards. Last trunk-segment angularly produced laterally. ‘Tail some-
what exceeding half the length of the anterior division; genital segment conspicu-
ously dilated in front, though the width is somewhat less than the length. Caudal
rami moderately slender, exceeding in length a little the last 2 segments combined,
and slightly divergent, being linear in form, and each provided dorsally with a
distinct longitudinal keel, inner edge finely ciliated; seta of outer edge rather
small and not much remote from the end; apical sete comparatively short, the
inner medial one only very little longer than the outer and scarcely twice as
long as the corresponding ramus, seta of inner corner not much longer than that
of the outer. Anterior antenne of moderate length, reaching, when reflexed, to
the middle of the 2nd segment, and composed of 17 joints. Natatory legs with
3 spines outside the terminal joint of the outer ramus of Ist and 2nd pairs;
inner edge of same joint carrying in Ist pair 3, in the succeeding pairs 4 sete.
Inner ramus of 4th pair moderately slender, with the outer apical spine some-
what exceeding half the length of the inner. Last pair of legs with the distal
joint not twice as long as it is broad, lateral spine rather strong and attached
about in the middle of the inner edge. Ovisacs comparatively large, oval in
form, and borne closely appressed to the sides of the tail. Seminal receptacle
transversely truncated in front.

1) Many other synonyms have been given in the work of Dr. Schmeil. But as he
evidently has combined several species under the name strenuus, only those synonymes are here
guoted, which more strictly may refer to the species here under consideration.

Copepoda

Pata

-— ' j ‘“/
“ tg ; { nh)
4 .
Va ] ~\ /
4 i a -\ ‘
: AN sy } "; a
rt »\ Fax a | }
a} : ee Vis Sea j
ryt eee YD j
‘ 1 ey wh f
ne = 1 i Ns
— < > Z - Ith, CEA
A * q So = me

SS

ee

Cyclopoida.

GaiOs Sars) dels

Oithonide.

Oithona spinirostris, Claus.

Copepoda

Pie rie

Cyclopoida.

Oithonide.

> >
Sana ee

a
Sal

KS
Sy WSS

Re ee : EAE
SVC ERISA

nnn a OD
See

WRI

‘ ee
Bee Ba mip ttigahatatbgat a OTA

iia

G. ©. Sars, del.

(Continued).

Oithona spinirostris, Claus.

Copepoda

Bike.

Cyclopoida.

Oithonige.

“4 mt 4
4] | i
er NY

Wien

+

SS
SN \ r POC Pes
a 4 a ~ " amauta rt F
~ WAL ee a j fe
: a a4 . ne reat Wig ;
. a : : \ j
BE RE a eed SLD rack. Bx ? | See =
vt Pipes aN: BEAN es
MS ee al

A =% Y <a = - "6 3!

Zr ae Ln eee
mS,

"4

Gx Heft:
f3\) ie yt

ren mal 5

G. O. Sars, del.

Oithona helgolandica, Claus.

Copepoda

Cyclopinide. Cyclopoida. Pl, IV.

G. O. Sars, del.

Cyclopina gracilis, Claus.

Copepoda

Pie

Cyclopoida.

Cyclopinide.

Za ro eee
Be es oe

Z
noe
<—e

—

G. O. Sars, del.

Cyclopina longicornis, Boeck.

Copepoda

PisViil:

Cyclopoida.

Cyclopinide.

Cyclopina brevifurea, G. O. Sars.

G. ©. Sars, del.

_ <u “i
a

Copepoda

Ply Vile

Cyclopoida.

Cyclopinidz.

GasOe Sars,edel:

Cyclopina elegans, Scott.

Copepoda

Pl. VILE

Cyclopoida.

Cyclopinide.

Cyclopinella tumidula, G. O. Sars.

G. O. Sars, del.

Copepoda

Cyclopinide. Cyclopoida. Pl. IX.

GeO ee Sars, del:

Cyclopetta difficilis, G. O. Sars.

Copepoda

PIX

Cyclopoida.

Cyclopinide.

Gz OF Sats), del:

Pterinopsyllus insignis, Brady.

Copepoda

Pi 2al2

Cyclopoida.

Cyclopinide.

GeO Sarsdel:

Pterinopsyllus insignis, Brady.
(Male)

Copepoda

Pix

Cyclopoida.

Cyclopide.

whet tc RE

GAO] sats. del.

Euryte longicauda, Philippi.

Copepoda

Cyclopide. Cyclopoida. Pl. XIII.

G. O. Sars, del.
_Euryte robusta, Giesbr.

Copepoda

Pl xv;

Cyclopoida.

Cyclopide.

G. ©. Sars; del.

Euryte curticornis, G. O. Sars.

Copepoda

Pls xave

Cyclopoida.

GzOF Sars) dell

Cyclopidz.

Halicyclops magniceps (Lilljeb.).

Copepoda

Cyclopoida. Pl. XVI.

Cyclopide.

del.

Ga Os Sars:

Cyclops strenuus, Fischer.

Lp Ot *y
Nah j :
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_ WITH SHORT DESCRIPTIONS, AND FIGURES OF ALL THE SPECIES: —

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| CYCLOPIDZ (continued)

BOTS ea OER A ay WITH 16 AUTOTYPIC PLATES

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SS SURE OSs oso ‘CAMMERMEYER’S FORLAG, CHRISTIANTA
1913

33

Colour generally light yellow or orange.

Length of adult female 1.50—1.70 mm.

Remarks.—The present species is in all probability identical with the
form named by Jurine Monoculus quadricornis rubens, and also Cyclops pictus
of Koch may be the same species. As, however, some doubt might arise about
the identity, this species has generally been recorded under the name proposed
by Fischer, who indeed was the first to give a recognisable description of it.
Both C. brevicaudatus, Claus and C. Clausi, Lubbock are undoubtedly referable
to the present species, which may be regarded as the type of the genus Cyclops
as defined here.

Occurrence.—This is one of our commonest Cyclopses, being very abundant
in small ponds and tarns, especially early in the spring. It is not, like most
other species of the present genus, a strict bottom-form, but is generally found
close to the surface of the water, swimming about rather quickly in the usual
jumping manner. Male specimens are at first rather scarce, but become more
numerous later in the season. ‘I'wo varieties occur, the one of rather smaller
size than the other and of lighter colour, and found in somewhat larger tarns.
I have, however, failed to detect any other difference between the 2 forms.

Distribution.—Throughout Europe, central and northern parts of Asia,

Bear Island, Spitsbergen, Algeria.

15. Cyclops abyssorum, G. O. Sars.
(P]. XVII).

Cyclops abyssorum, G. O. Sars, Oversigt af de indenlandske Ferskvandscopepoder, Chr. Vid.
Selsk. Forhandl. 1862, p. 29.

Syn.: C. strenuus, var. tenwipes, G. O. Sars.

Specific Characters.—Female. Body comparatively more robust than in
C. strenuus, with the anterior division more tumefied in its anterior part. Cephalic
segment obtusely rounded in front. Lateral parts of penultimate trunk-segment
terminating in a well-marked dentiform point curving outwards. Last trunk-
segment acutely produced laterally. Genital segment considerably dilated in front,
its greatest width exceeding the length. Caudal rami very slender and narrow,
exceeding somewhat in length the last 3 caudal segments combined, and rather
divergent, each having dorsally a very distinct longitudinal keel, inner edge coarsely
ciliated, seta of outer edge small and attached near the end, apical sete com-
paratively longer and thinner than in C. strenwus, the imner medial one almost
attaining the length of the tail, seta of inner corner twice as long as that of the
outer. Anterior antenne much more slender and elongated than in C. strenuwus,

5 — Crustacea.

34

reaching, when reflexed, considerably beyond the 2nd segment, and having some
of the marginal setz rather slender. Posterior antenne with the terminal joint
longer than the penultimate one and much narrower. Anterior maxillipeds with
the claw of the 2nd basal joint comparatively longer than in C. strenuus. Nata-
tory legs having the same number of spines and sete as in that species, rami,
however, considerably more slender, especially those of 4th pair; apical spines
of inner ramus in this pair more elongated, the outer one about half as long as
the inner. Last pair of legs with the proximal joint comparatively less broad
than in C. strenuus, distal joint about twice as long, and having the lateral spine
of moderate size and attached nearly in the middle of the inner edge. Ovisacs
smaller than in the preceding species and rounded oval in form, each containing
a rather limited number of ova. Seminal receptacle comparatively small, with
the anterior part evenly rounded.

Colour whitish grey, with a slight yellow tinge more distinct on the tail.

Length of adult female 1.80—1.90 mm.

Remarks.—The above-described form is closely allied to C. strenwus, and
has indeed by most recent authors been regarded as only a variety of that species.
We know, however, at present of several species exhibiting a similar close relation-
ship to C. strenuwus, and together forming a natural group of Cyclopses. All of
these have, it is true, been combined by Dr. Schmeil in a single species; but in
recent time, the specific distinctness of some of these forms has been fully recog-
nized. Thus Lilljeborg, in his account of the Swedish Cyclopses (1901), de-
scribes as well-defined species the 2 forms C. scutifer, G. O. Sars and C, vicinus,
Uljanin, which are both recorded by Dr. Schmeil as only synonyms of C. strenwus.
Though Lilljeborg was inclined to regard the present form as merely a “luxuri-
ant” deep-water variety of C. strenuus, it is in my opinion fully as distinct from
that form as are the 2 just-named species. On a closer comparison, it is in reality
found to differ conspicuously from C. strenwus, both as to its outward appear-
ance and the structure of some of the appendages. Among more easily observable
differences I may mention the greater length of the anterior antennz, the very.
narrow form of the caudal rami, and the somewhat different mutual relation in the
length of the apical sete. It may moreover be noted here, that the form of the
seminal receptacle, on which Dr. Schmeil laid so much stress for the discrimination
of species, is in the present species rather different from that in C. strenuus, as
shown by the figures given in the 2 respective plates. The form recorded by
me from the lake Telecki in Altai as C. strenwus, var. gracilipes, I now find to

be more properly referable to the species here under consideration.

Sab

Oceurrence.—I first found this species in the Maridal Lake near Christiania,
where it occurred only in the deepest part of the lake, at the considerable depth
of 40—50 fathoms; hence the specific name proposed. Prof. Brady has taken it
under quite similar circumstances in some of the British lakes. Besides in the
Maridal Lake, I have observed this form in the Vansjo, near Moss, and in the
Stensfjord, a branch of the great lake, Tyrifjord. In the last-named locality it
occurred rather frequently at depths varying from 6 to 12 fathoms, muddy bottom.
The specimens from all 3 localities agree perfectly with each other, and the
figures given by Prof. Brady show the British form also to be in full accordance
with the Norwegian one.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), Central Asia
(the present author).

16. Cyclops lacustris, G. O. Sars.
(Pl. XVIII).
Cyclops lacustris, G, O. Sars, |. ¢., p. 30.

Specific Characters.— Female. Body moderately slender, with the anterior
division oblong oval in form, greatest width about half the length and occurring
somewhat in front of the middle. Cephalic segment comparatively large, with the
frontal part almost transversely truncated. Lateral parts of penultimate trunk-
segment not at all produced, being of the very same appearance as in the 2
preceding segments. Last trunk-segment likewise only very slightly prominent
laterally. Genital segment of a rather characteristic form, being considerably
longer than it is broad and abruptly narrowed in the middle, with the anterior
part moderately dilated, the posterior part cylindric in shape. Caudal rami not
attaining the length of the 3 preceding segments combined, and slightly divergent,
dorsal keel obsolete, inner edge very finely ciliated, seta of outer edge small and
not very far from the end, apical setz rather slender, the inner medial one
attaining fully the length of the tail, seta of inner corner more than twice as
long as that of the outer. Anterior antenne rather slender, reaching, when
reflexed, beyond the 2nd segment of the body. Anterior maxillipeds with the
claw of the 2nd basal joint unusually slender. Natatory legs exhibiting an arma-
ture similar to that in the 2 preceding species, rami comparatively slender, with
very long sets; outer apical spine of inner ramus in 4th pair rather small,
scarcely exceeding */; of the length of the inner. Last pair of legs with the
distal joint rather narrow, sublinear in form, lateral spine extremely minute and

attached at about the middle of the inner edge, apical seta, on the other hand,

unusually long and slender. Ovisacs small, rounded, and each containing a very
limited number of ova. Seminal receptacle comparatively larger than in C. abys-
sorum, anterior part evenly rounded, posterior part rather produced. Spermatophores
attached to the genital opening of about the same appearance as in C. strenuus.

Body highly pellucid, with a very faint bluish or greenish tinge.

Length of adult female 1.50 mm., of male 1.30 mm.

Remarks.—In the case also of the present form the specific validity has
not been admitted by recent authors, though in my opinion it is a very well-defined
species, Lilljeborg was inclined to regard it as a variety of C. strenwus, which
has adapted itself to a limnetic life. On a closer examination, however, the
well-marked differences which this form exhibits cannot by any means be explained
in this way, nor be regarded as simply accidental or varietal.

Occurrence.—I have only met with this form in our 2 largest lakes,
Mjosen and Tyrifjord. It lives there as a true limnetic form together with Limno-
calanus macrurus and other midwater forms, being generally found swimming
about close to the surface of the water.

Distribution.—Sweden (Lilljeborg).

17. Cyclops scutifer, G. O. Sars.
(Pl. XIX).
Cyclops scutifer, G. O. Sars, J. ¢., p. 28.

Specific Characters.—Female. Body comparatively slender, with the
anterior division narrow oblong in outline, greatest width scarcely attaining half
the length, and occurring somewhat in front of the middle. Lateral parts of the
last 2 trunk-segments greatly produced, being expanded to triangular exstant
lamelle, which are more or less contiguous, so as to present, together with the
corresponding segments, the appearance of a quadrangular shield obtecting the
posterior part of the trunk. Genital segment comparatively large and very much
dilated in front, with a small knob-like prominence on each side, posterior part
gradually narrowed. Caudal rami scarcely longer than the last 2 segments combined
and only very slightly divergent, dorsal keel only faintly indicated, inner edge
finely cilated; seta of outer edge rather remote from the end, apical sete very
unequal in length, the inner medial one much the longest, seta of inner corner
more than twice as long as that of the outer. Anterior antenne rather slender,
reaching, when reflexed, considerably beyond the 2nd segment of the body, and
clothed with comparatively long sete. Posterior antennz with the terminal joint

scarcely longer than the penultimate one. Anterior maxillipeds resembling in

structure those in C. lacustris. Natatory legs armed as in the 3 preceding species,
rami moderately slender, the inner one in 4th pair with the outer apical spine
very small; spines of outer ramus in all pairs rather thin; seta attached inside
the Ist basal joint in 4th pair much coarser than in the other pairs. Last pair
of legs with the proximal joint comparatively small, distal jomt more than twice
as long, with the lateral spine of moderate size and attached somewhat beyond
the middle. Ovisacs generally very small, rounded, each containing a very limited
number of ova. Seminal receptacle of moderate size and evenly rounded both
in front and behind. Spermatophores attached to the genital opening unusually
large, projecting beyond the side of the genital segment.

Body highly pellucid and generally almost colourless, in some cases,
however, exhibiting a beautiful emerald green hue.

Length of adult female 1.20—1.40 mm, of male 1.10 mm.

Remarks.—This form was considered hy Dr. Schmeil as only a variety of
C. strenuus; but Lilljeborg has subsequently, in his account of the Swedish Cy-
clopses, vindicated its specific distinctness. It is especially recognisable by the
extraordinary development in the female of the epimeral plates on the last 2
trunk-segments, which gives the body a rather characteristic appearance and
has indeed given rise to the specific name scutifer.

Occurrence.—I have met with this form rather abundantly in several of
our larger lakes, for instance in the Maridal and Lut Lakes near Christiania, where
it lives as a true limnetic form. It also occurs in mountain lakes at the limit
of perpetual snow, and is indeed the only Crustacean to be found there.

Distribution.—Sweden (Lilljeborg), Northern part of Siberia (the present

author).

18 Cyclops vicinus, Uljanin.
(Pl. XX).
Cyclops vicinus, Uljanin, Crustacea of the Expedition of A. Fedtschenko in Turkestan (in Russian).
peso Ohy PIR xe hostel 7,
Syn.: Cyclops strenwus, Schmeil (not Fischer).
2 ,» pulchellus, Brady (not Koch).

Specific Characters.— Female. Body moderately slender, with the anterior
division oblong oval in form and somewhat tumefied in front. Lateral parts of
penultimate trunk-segment produced in the form of acutely triangular extant
lappets; those of last segment likewise produced, though Jess so than in C. sewtifer.
Genital segment about as long as it is broad at the base, and gradually narrowed

behind. Caudal rami long and slender, equalling in length the last 3 segments

combined, and only slightly divergent, dorsal keel well marked, inner edge
minutely ciliated; seta of outer edge not very far from the end, apical sete
not much elongated, the inner medial one about twice the length of the ramus,
seta of inner corner more than twice as long as that of the outer. Anterior
antennze comparatively shorter and stouter than in the preceding species, reaching,
when retlexed, scarcely beyond the middle of the 2nd body-segment; number of
joints generally only 16, the 8th and 9th joints being confluent. Posterior an-
tenn with the terminal joint a little longer and narrower than the penultimate
one. Natatory legs with the rami moderately slender, terminal joint of outer
ramus in all pairs with only 2 spines outside; outer apical spine of inner ramus
in 4th paw very small and rudimentary. Last pair of legs resembling in shape
those in C. strenuus, the distal joint being rather short and stout, with the
lateral spine well developed and attached about in the middle. Ovisacs of moderate
size and oval in shape. Seminal receptacle comparatively small, resembling that
in OC. abyssorum.

Colour, according to Lilljeborg, somewhat variable, the body being in
some cases of a unitorm whitish grey hue, in other cases tinged with brownish
red or reddish yellow.

Length of adult female about 1.70 mm.

Remarks.—This form was first described by the Russian naturalist
Uljanin, but was subsequently considered by Dr. Schmeil to be only a variety
of C. strenwus. Its specific distinctness has, however, been vindicated by Lillje-
borg, and I have myself, by an examination of specimens from Mongolia, had an
opportunity of confirming this view. The habitus-figure given in Dr. Schmeil’s
work, as pointed out by Lilljeborg, evidently refers to this species, and also the
form described in Prof. Brady’s Monograph as C. pulchellus, is unquestionably
referable to the same species.

The most conspicuous character distinguishing this form from C. strenuwus
is the very prominent lateral parts of the last 2 trunk-segments, in which
respect it somewhat resembles C. scwtifer. It differs, however, very markedly
both from this and the 3 other species described above, in the armature of the
natatory legs, the terminal joint of the outer ramus having in all pairs only 2
spines outside.

Occurrence.—This form, it is true, has not yet been observed within the
limits of our country; but I cannot doubt that, on a closer investigation, it will
be found to occur at any rate in the south-eastern part of the country, since
Lilljjeborg has recorded it from immediately adjacent tracts of Sweden. The

figures here given are from specimens found in a sample taken in the delta of

39

the Volga, and kindly sent to me for examination from the Zool. Museum of
St. Petersburg.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil),
Turkestan (Uljanin), Mongolia and Mouth of Volga (the present author).

19. Cyclops insignis, Claus.
(Pl XXI).
Cyclops insignis, Claus, Weitere Mittheilungen itber Cyclopiden, Arch, Nat. Hist. 23 Jahrg. Bd. 1,
px 209), Pl. Xd, fies, -8—13.

Syn.: Cyclops quadricornis, Koch.

Specific Characters—Female. Body rather slender, though having the
anterior division somewhat dilated and of regularly elliptical form, its greatest
width somewhat exceeding half the length and occurring in the middle. Lateral
parts of penultimate trunk-segment not produced, and of same shape as those of
the 2 preceding segments. Last trunk-segment rather broad and sharply pointed
on each side. ‘Tail slender and attenuated, though shorter than the anterior
division; genital segment very broad in front and abruptly constricted behind.
Caudal rami long and slender, considerably exceeding in length the last 3 seg-
ments combined, and narrow linear in form, being only very slightly divergent,
each ramus exhibiting dorsally a very distinct longitudinal keel; seta of outer
edge somewhat remote from the end, apical sets not much elongated, the inner
medial one being scarcely more than twice as long as the ramus, seta of inner
corner very little longer than that of the outer, which is rather strong, almost
spiniform. Anterior antenne of moderate length, reaching, when reflexed, about
to the middle of the 2nd segment of the body, and composed of only 14 joints,
the 8th to 11th joints being coalesced into a single elongate segment. Posterior
antennz with the terminal joint scarcely longer than the penultimate one. Nata-
tory legs more strongly built than in the preceding species, terminal joint of outer
ramus in all of them having only 2 spines outside; outer apical spine of inner
ramus in 4th pair less rudimentary, exceeding half the length of the inner. Last
pair of legs with the distal joint rather narrow and somewhat constricted near
the base, lateral spine of moderate size and attached about in the middle.
Ovisacs large, oval, and carried closely appressed to the sides of the tail. Seminal
receptacle short and broad, of a somewhat irregular transversely elliptical form
and not produced behind. Spermatophores attached to the genital opening placed
at right angles to the axis of the body.

Colour yellowish, with a more or less distinct olivaceous tinge.

Length of adult female amounting to 2.60 mm.

Remarks—This is an easily recognisable species, though, according to
the structure of the several appendages, it seems to be referable to the same
group as the 4 preceding species. It is, however, at once distinguished from
them by its much larger size, the 14-articulate anterior antenne, the peculiar
shape of the genital segment, and the long and slender caudal rami. The C.
qvadricornis of Koch seems to be this species; but as the name qvadricornis is
a collective one, it cannot be maintained. The form recorded by Brady as C.
insignis is scarcely that species.

Occurrence.—I have taken this form in great numbers early in the spring
from ponds near Christiania. Later in the summer it was not observed.

Distribution.—Sweden (Lilljeborg), Germany (Schmeil), Bohemia (Fric).

20. Cyclops vulgaris, Koch.
(Pl. XXII.
Cyclops vulgaris, Koch, Deutschlands Crustaceen, Myriopoden und Arachniden, Heft 2], Tab. 4.
Syn.: Monoculus qvadricornis viridis, Jurine.
Cyclops viridis, Fischer,
brevicornis, Claus.

Specific Characters.—Female. Body comparatively robust, with the anterior
division rather dilated and broadly oval in form, greatest width considerably
exceeding half the length Cephalic segment very large and broadly rounded in
front. Lateral parts of penultimate trunk-segment of same appearance as those
of the 2 preceding segments. Last trunk-segment only slightly produced laterally.
Tail scarcely exceeding half the length of the anterior division; genital segment
moderately dilated in front and gradually narrowed behind. Caudal rami scarcely
longer than the last 2 segments combined, and only very slightly diverging,
without any dorsal keel, but with the inner edge finely ciliated; seta of outer
edge not very far from the end, middle apical setw rather elongated, the inner
one attaining half the length of the body; seta of inner corner more than
twice as long as that of the outer. Anterior antenne not very slender, being
scarcely longer than the cephalic segment, and composed of the usual number
of joints (17). Posterior antennz with the terminal joint longer than the penulti-
mate one. Anterior maxillipeds more strongly built than in the preceding species.
Natatory legs likewise rather strong; terminal joint of outer ramus in all of them
with only 2 spines outside, inner edge of same joint in the Ist pair with only
2 sete, in the other pairs with 3 sete; apical spines of inner ramus in 4th pair
of almost equal size. Last pair of legs with the proximal joint unusually broad
and conically produced outside, distal joint very small, with the lateral spine

extremely minute and rudimentary. Ovisacs large, fusiform in shape, and con-

siderably divergent. Seminal receptacle with the anterior part transversely ellip-
tical in form and sharply defined from the posterior part, which is exserted on
each side to a band-like stripe.

Colour rather variable, in some cases bluish green, in other cases with
a distinct olivaceous tinge, and not uncommonly light whitish grey, with dark
patches at the end of the segments.

Length of adult female amounting to 1.90 mm.

FRemarks.—This form has generally been recorded under the name
C. viridis Jurine. I consider it, however, to be scarcely admissible to appropriate
as specific designations the several varietal names appended by Jurine to his species
Monoculus qvadricornis and merely indicating the diversity in colour found by
him in different specimens. As moreover the colour both in the present species
and in several other Cyclopses is rather variable, the Jurinian names would in
fact be of very little significance to the species. The form recorded by Koch as
C. vulgaris is unquestionably this species, and as the name viridis applied to the
species by Fischer is of much later date, it must cede to that proposed by Koch.
The C. brevicornis of Claus is likewise identical with the present species. On the
other hand, the North American form named by Herrick C. viridis var. ameri-
cana, is scarcely the same species, as the armature of the natatory legs is
essentially different.

The present species, which belongs to the group of Cyclopses distinguished
by Dr. Schmeil as the bicuspidatus group, may be easily recognised by its
comparatively robust body, the large divergent ovisacs, and the peculiar structure
of the last pair of legs.

Occurrence.—It is one of our commonest Cyclopses, and thus fully deserves
the specific name proposed for it by Koch. I have met with it at all seasons
of the year, both in small ponds and ditches and in larger Jakes, where it descends
to rather considerable depths.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil),
France (Richard), Russia (Fischer), Central Asia and Siberia (the present author).

21. Cyclops gigas, Claus.
(PI. XXTID).
Cyclops gigas, Claus, Weitere Mittheilungen iiber Cyclopiden; Arch. Nat. Hist 23 Jahrg, B. 1,
Bp. 201 Pie xyes. 1—).

Syn.: Cyclops ingens, Herrick.
Specific Characters,—Female. Body much larger than in C. vulgaris and
of a somewhat more slender form, though otherwise exhibiting a very similar

6 — Crustacea.

42

appearance. Caudal rami, however, conspicuously more produced, even exceeding
in length the last 3 segments combined, and only very slightly divergent; middle
apical sete rather slender, the inner one being considerably longer than the tail,
seta of inner corner comparatively shorter than in C. vulgaris, not attaining twice
the length of the outermost one. Both pairs of antennz of a very similar structure
to that in the said species. Natatory legs Jikewise rather similar; apical spines
of inner ramus in 4th pair, however, conspicuously more slender. Last pair of
legs, as in C. vulgaris, with the proximal joint rather expanded and conically
produced outside, distal joint, however, comparatively narrower, with the lateral
spine almost obsolete. Ovisacs very large and of a somewhat irregular form,
projecting far beyond the caudal rami, and less divergent than in C. vulgaris.
Seminal receptacle with the anterior part comparatively larger than in that species,
occupying almost the whole width of the genital segment.

Colour light yellowish brown, with a more or less distinct olivaceous or
greenish tinge.

Length of adult female amounting to 2.50 mm.

Remarks.—This form has been considered by Dr. Schmeil and several
other authors to be only a large variety of the preceding species. Lilljeborg has,
however, vindicated its specific distinctness, and I have myself, by a careful com-
parison, come to the same result. It may be at once distinguished from C. vul-
garis, not only by its unusually large size, but also by the much more produced caudal
rami, and by the somewhat different mutual relation in the length of the apical sete.
The last pair of legs also, though somewhat resembling those in the said species,
differ slightly in the shape of the distal joint. Finally, the seminal receptacle
is of a somewhat different shape, as shown by the figure here given. The North
American form C. ingens of Herrick seems to be referable to the present species.

Occurrence.—I have taken this form in great abundance from some small
ponds near Christiania. The specimens were observed early in the spring, even
before the ice was wholly melted, and as all of them at that time were fully
grown and to some extent thickly covered with Epizoa, they must have developed
at a much earlier period, during the winter. Later in the spring their number
decreased gradually. and at the approach of the summer they seemed wholly to
have disappeared. The species also occurs in some of our larger lakes and more
generally in very considerable depths. In Lake Mjosen I have even taken it
at the great depth of 100 fathoms; and though most of the specimens there
obtained were immature, they could with full certainty be adduced to the present
species, on account of the considerably produced caudal rami. Lilljeborg has

found the species under quite similar circumstances in some of the Swedish lakes.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), Germany (Claus),
Bear Island (Lilljeborg), North America (Herrick).

22. Cyclops capillatus, G. O. Sars.
(Pl. XXIV).
Cyclops capillatus, G. O. Sars, 1. ¢., p. 39.

Specific Characters.—Female. Body not very slender, resembling some-
what in its general form that in C. vulgaris, anterior division regularly elliptical
in outline, with the greatest width somewhat exceeding half the length and occurring
in the middle. Lateral parts of penultimate trunk-segment of same shape as
those on the 2 preceding segments. Last trunk-segment comparatively small, not
produced laterally. Genital segment resembling in shape that in C. vulgaris,
being about as long as it is broad at the base. Caudal rami comparatively
slender, almost attaining the length of the last 3 segments combined, and not
at all divergent; seta of outer edge rather slender and far from the end, being
attached near the middle; middle apical sete slender, the inner one attaining
half the length of the body; seta of inner corner scarcely longer than that of
the outer. Anterior antenne about the length of the cephalic segment, and
composed of only 12 joints, the 7 short articulations intercalated in other species
between the 7th and the antepenultimate joint being in the present form by
concrescence reduced to 2 elongated segments; lateral sete of the antenne un-
usually long and slender. Posterior antennz with the terminal joint considerably
longer than the penultimate one. Natatory legs moderately slender, terminal
joint of outer ramus im all of them armed outside with 3 spines, inner edge of
same joint in lst pair with 3, in the other pairs with 4 sete; inner ramus of
4th pair very narrow, with the terminal joint fully as long as the other 2 com-
bined, apical spines of this ramus slender and elongated, the inner one slightly
longer than the outer. Last pair of legs with the proximal joint rather broad
and expanded, distal jomt much smaller, rounded oval in form and having the
lateral spine very small. Ovisacs narrow fusiform in shape and greatly diverging.
Seminal receptacle with the anterior part transversely oval and evenly rounded
in front, posterior part only slightly produced.

Colour yellowish, with a more og less distinct olivaceous or brownish tinge.

Length of adult female about 1.80 mm.

Remarks.—This is a very distinct species, though in size and general
appearance somewhat resembling C. vulgaris. From this species it is, however,
markedly distinguished by the smaller number of joints in the anterior antenne,

the structure of the caudal rami, and the rather different armature of the nata-
tory legs.

Occurrence.—I have found this form only quite occasionally in 3 different
localities, viz., in the Maridal Lake near Christiania, in Mjosen and in Tyrifjord.
In all 3 localities it occurred at a depth of from 2 to 6 fathoms on a muddy
bottom.

Distribution.—Sweden (illjeborg).

23. Cyclops lucidulus, Koch.
(Pl. XXV).
Cyclops lucidulus, Koch, 1. c. Heft 21, 10.
Syn.: Cyclops vernalis, Fischer.
» elongatus, Claus.
= » parcus, Herrick.

Specific Characters.— Female. Body comparatively slender and attenuated,
with the anterior division oblong oval in form, greatest width about half the
length and occurring somewhat in front of the middle. Lateral parts of the
pedigerous segments rather prominent, those of penultimate segment terminating
in a tooth-like projection curved outwards. Last trunk-segment rather broad, and
acutely produced on each side. Genital segment conspicuously dilated in front
and gradually tapered behind. Caudal rami rather long and slender, equalling
in length the last 3 segments combined, and scarcely at all divergent; seta of
outer edge attached not far from the end, middle apical sete long and slender,
the inner one exceeding the length of the tail; seta of inner corner very thin
and somewhat longer than that of the outer, which is rather thick, spiniform.
Anterior antenne scarcely longer than the cephalic segment, and generally com-
posed of the normal number of joints (17), though-in some cases 18 joints may
be counted, on account of a subdivision of the 7th joint. Posterior antennz with
the terminal joint about the length of the penultimate one. Natatory legs com-
paratively strongly built, with the spines rather coarse and varying somewhat in
number, the terminal joint of the outer ramus having in some cases 3 spines
outside in one or other of the pairs instead of the usual number (2); sete of
inner edge of this joint in Ist pair 2, in the other pairs 3; apical spines of
inner ramus in 4th pair subequal in size. Last pair of legs very small, proximal
jomt not much dilated, distal joint narrow, with the lateral spine of moderate
size and attached near the end. Ovisacs comparatively large, oval in form, and

only slightly diverging. Seminal receptacle transversely elliptical in form, and

ae

scarcely produced at all behind. Spermatophores attached to the genital opening
small and placed longitudinally close together.

Colour light yellowish, with a more or less distinct reddish or ochra-
ceous tinge.

Length of adult female 1.40—1.50 mm.

Remarks.—I have thought it right to maintain my original identification
of this form with C. lucidulus of Koch, in spite of the controversy of Dr. Schmeil.
It is true, that the description given by Koch of this species, as pointed out by
Dr. Schmeil, is quite insufficient, but nevertheless I find it possible to recognise the
species from the figure accompanying the description, and Dr. Rehberg is also of
opinion that my identification is correct. The species has generally been recorded
under the name vernalis proposed for it by Fischer; but this name is of much later
date than that given to the species by Koch. The Cyclops elongatus of Claus
is certainly the same species, and this is also the case with the North
American form C. parcus, Herrick, of which I have had specimens for examination
kindly sent to me by Prof. Forbes. From the 3 preceding species it is easily
distinguished by its slender elongated body, rather resembling in this respect some
of the succeeding species, especially C. pulchellus and C. bisetosus. It is, how-
ever, well distinguished also from these species by several well-marked characters,
as shown hereafter.

Occurrence—The present species is found rather commonly throughout
the whole country in shallow pools and ditches. Especially early in the spring
it abounds in nearly all the ponds round Christiania, but is also met with,
though not so frequently, at other seasons. A smaller variety is often found
having the caudal rami somewhat shorter, but otherwise agreeing with the typi-
cal form.

Distribution.—Throughout Europe, Central Asia, New Siberian Islands,
Ceylon, North America.

24. Cyclops robustus, G. O. Sars.
(Pl. XXVI).
Cyclops robustus, G. O. Sars, |. ¢., p. 36.

Syn.: Cyclops brevispinosus, Herrick.

Specific Characters.—-Female. Body considerably more robust than in
the preceding species, with the anterior division rather dilated and oval in form,
ereatest width exceeding half the length and occurring about in the middle.

Cephalic segment very large and evenly rounded in front. Lateral parts of

46

penultimate trunk-segment conspicuously produced, each terminating in a sharp,
somewhat extant point. Last trunk-segment likewise acutely produc,d laterally.
Genital segment longer than it is broad at the base, anterior part slightly dilated,
posterior sub-cylindrical in shape. Caudal rami comparatively shorter and less
narrow than in C. lucidulus, not attaining the length of the last 3 segments
combined, and scarcely divergent; seta of outer edge rather coarse and somewhat
remote from the end; apical sete unusually strong, almost spiniform, the inner
medial one nearly attaining half the length of the body and, like the outer one,
quite smooth in its proximal half, the remaining part being clothed with short,
coarse hairs; seta of inner corner only slightly longer than that of the outer.
Anterior antennz scarcely as long as the cephalic segment, and composed of the
normal number of joints (17). Posterior antenne with the terminal joint not
longer than the penultimate one. Natatory legs comparatively strongly built;
terminal joint of outer ramus in all of them armed outside with 3 coarse spines
and having the normal number of sete inside; seta attached outside the terminal
joint of the inner ramus in Ist pair of normal appearance, in the other pairs,
however, transformed into a strong denticulated spine; apical spines of same ramus
in 4th pair subequal in size. Last pair of legs somewhat resembling those in
C. vulgaris, the proximal joint being considerably expanded, and the distal joint
of inconsiderable size, with the lateral spine very minute. Ovisacs of moderate
size and oval in form, being only slightly divergent. Seminal receptacle trans-
versely elliptical in form, and only very slightly produced behind.

Colour light yellowish brown.

Length of adult female 1.20 mm.

Remarks.—Dr. Schmeil does not admit the specific validity of this form,
which he only regards as a variety of the preceding species. I think, however,
that it ought to be kept apart, and Lilljeborg has also, in his account of the
Swedish Cyclopses, described it as a well-defined species. It may indeed readily
be distinguished from C. lucidulus by its much more robust body, for which
reason also the specific name robustus was proposed by the present author. In
the structural details also several well-marked differences are found to exist, as
shown in the above-giyven diagnosis. According to Lilljeborg, the North American

form C. brevispimosus Herrick is identical with the present species.

Occurrence.—This form seems in our country to be of rather rare occur-
rence. I have only met with it quite occasionally at the border of 3 of our
larger lakes, viz., the Nordsjo Lake, Maridal Lake and Mjgsen. In habits it is
a true bottom-form, keeping constantly close to the ground.

Distribution.—Sweden (Lilljeborg), North America (Herrick).

25. Cyclops pulchellus, Koch.
(Pl. XXVID.
Cyclops pulchellus, Koch, 1. c. Heft 21, 2.
Syn.: Cyclops bicuspidatus, Claus.

‘ Es LIubbocki, Brady.
s a insignis, Brady (not Claus).
* “ odessanus, Schmankewitsch.
- » helgolandicus, Rehberg.

Specific Characters.—Female. Body rather slender and attenuated, with
the anterior divison oblong oval in outline, greatest width about equalling half
the length and occurring in the middle. Lateral parts of penultimate trunk-
segment not extant, resembling in shape those of the 2 preceding segments.
Last trunk-segment only slightly produced laterally. Genital segment comparatively
large and gradually narrowed behind. Caudal rami long and slender, generally
attaining the length of the last 3 segments combined, and not at all divergent;
seta of outer edge at a considerable distance from the apex, being attached
not far from the middle of the corresponding ramus; middle apical sete rather
slender, the inner one being much the Jonger and about equalling the tail in
length; seta of inner corner very little longer than that of the outer, and much
thinner. Anterior antenne about the length of the cephalic segment and gener-
ally 17-articulate; in some instances, however, by the concrescence of the 8th to
11th joints, only 14-articulate. Posterior antenne with the terminal joint slightly
longer and narrower than the penultimate one. Natatory legs comparatively
slender, with only 2 spines outside the terminal joint of the outer ramus; apical
spines of inner ramus in 4th pair rather unequal, the outer one being much the
larger. Last pair of legs with the proximal joint comparatively small, distal
joint more than twice as long, and narrow linear in form, lateral spine rather
slender and attached at a short distance from the end. Ovisacs generally narrow
oblong or fusiform in shape, and considerably diverging. Seminal receptacle with
the posterior part rather produced.

Colour generally yellowish, with a more or less distinct orange or reddish
tinge, in some instances, however, uniformly whitish grey.

Length of adult female amounting to 1.30 mm.

Remarks.—My original identification of this form with C. pulchellus of
Koch has not been admitted by Dr. Schmeil, and the present species has there-
fore by most recent authors, and also by myself, been recorded under the name
bicuspidatus given to it by Claus. I now find, however, that there are so many
things which speak in favour of my former identification, that I have thought it

right to maintain it here. It must indeed be assumed that Koch has observed

48

this rather common Cyclops, and no other species can properly be identified with
his C. pulchellus than the present one. The C. Thomasi of Forbes, which
both by Dr. Schmeil and Lilljeborg is recorded as only a synonym of the
present form, is in reality a well-defined species, as J] have convinced myself by
an examination of specimens kindly sent to me by Prof. Forbes. The form at
first described by Prof. Brady as C. Lubbocki and subsequently as C. isignis
Claus, seems to be referable to the variety odessana of the present species, and
this is also the case with C. helgolandicus of Rehberg. I have been in some doubt
as to whether the said variety should not more properly be regarded as a separate
species, as it differs from the typical form not only in the smaller number of
joints in the anterior antennz, but also in the comparatively shorter caudal rami,
and in a somewhat different shape of both the inner ramus of the 4th pair of
legs and of the last pair of legs, as shown in the accompanying plate. The
characteristic position of the seta on the outer edge of the caudal rami, as also
the mutual relation of the innermost and outermost apical sete, is, however,
exactly as in the typical form, and I haye also found in some instances, that the
elongate 8th joint of the anterior antenne exhibits distinct traces of a subdivision
into the usual 4 short articulations.

Occurrence.—The present species is found not unfrequently in ponds and
ditches round Christiania, especially in the spring. I have also met with it
occasionally at the border of larger lakes, or in pools left by the reflux of the
water. In the living state it is easily recognised from the allied species ‘by the
considerably diverging ovisacs, the ova of which often exhibit a light reddish
colour, as indicated in the figure given by Koch. The variety odessana I have
taken early in the spring from small water-holes with grassy bottom, the water
of which very soon evaporated.

Distribution.—Throughout the greater part of Europe, Central Asia
(G. O. Sars), North America (Herrick).

26. Cyclops bisetosus, Rehberg.
(Pl. XXVIII).
Cyclops bisetosus, Rehberg, Beitrag zur Kentniss der freilebenden Siisswasser-Copepoden. Abhandl.
nat. Verein zu Bremen, Bd. VI, Heft 3, p. 543.

Syn.: Cyclops bicuspidatus, G. O. Sars (not Claus).
«

Specific Characters.— Female. Body still more slender and attenuated
than in the preceding species. Lateral parts of penultimate trunk-segment not

extant. Last trunk-segment slightly produced laterally. Genital segment rather

#0

tumid, being scarcely longer than it is broad. Caudal rami narrow and some-
what tapered, being about as long as the last 3 segments combined and not at
all diverging; seta of outer edge not far from the apex, middle apical setz
slender, the inner one exceeding the length of the tail; seta of inner corner
very small, shorter than that of the outer. Anterior antenne scarcely as long
as the cephalic segment, and 17-articulate. Posterior antennz with the terminal
joint a little longer than the penultimate one. Maxillipeds of the usual structure.
Natatory legs exhibiting a similar armature to that in the preceding species; rami,
however, comparatively shorter; terminal joint of inner ramus in 4th pair scarcely
longer than the middle one, and having the outer apical spine shorter than the
inner. Last pair of legs somewhat resembling those in C. pulchellus, though
having the distal joint comparatively shorter and the lateral spine less produced.
Ovisacs rather large, oval in form, and only slightly divergent. Seminal receptacle
with the anterior part surrounded by a clear area forming on each side an
auricular corner, posterior part somewhat produced and evenly rounded.

Colour whitish grey, with a more or less distinct reddish or brownish tinge.

Length of adult female 1.00 to 1.25 mm. |

Remarks.—This form was formerly erroneously identified by the present
author with CO. bicuspidatus Claus, which belongs to the preceding species. It
has subsequently been described by Dr. Rehberg as C. bisetosus, and this name
is now generally adopted for the present species. In its external appearance it
has a general resemblance to C. pulchellus, but is of somewhat smaller size, and
is moreover distinguished by some differences in the structure of the caudal rami
and legs, as also in the manner in which the ovisacs are carried in relation to
the axis of the body.

Occurrence.—This species is by no means uncommon. I have taken it
in many parts of the country, and always in very shallow pools and ditches,
which are subjected to more or less complete exsiccation during the summer.

Distribution Sweden (Lilljeborg), Germany (Schmeil), Siberia (G. O.
Sars), Spitsbergen (Richard).

27. Cyclops crassicaudis, G. O. Sars.
(PL XIX);
Cyclops crassicaudis, G. O. Sars, 1. ¢., p. 40.

Specific Characters.—Female. Body less slender than in the preceding
species, with the anterior division oblong oval in form, greatest width about
half the length and occurring somewhat in front of the middle. Lateral parts
of the trunk-segments somewhat prominent. Last trunk-segment rather broad,

7 — Crustacea.

being produced on each side to an acuminate projection pointing outwards. Tail
comparatively short and thick, exceeding only very slightly half the length of
the anterior division; genital segment unusually dilated throughout its whole
length, exhibiting a slight constriction in front of the middle. Caudal rami of
moderate size, about equalling in length the last 2 segments combined, and scarcely
at all divergent; seta of outer edge not far from the apex, middle apical! sete
slender, the inner one exceeding the length of the tail; seta of inner corner
extremely small and rudimentary, scarcely more than half as long as that of the
outer. Anterior antenne about the length of the cephalic segment, and com-
posed of only 12 joints, the 8th and 9th joints, as in C. capillatus, answering to
the 7 short articulations succeeding the 7th joint in other species. Posterior
antenne and maxillipeds about as in the preceding species. Natatory legs un-
usually short and stout, with the joints of the rami broad and expanded, number
of spines and setz as in the 2 preceding species; inner ramus of Ist pair with
the apical spine unusually strong and somewhat curved, that of 4th pair with the
terminal joint scarcely longer than the middle one, and having the inner apical
spine longer than the outer. Last pair of legs resembling in shape those in C. bise-
tosus. Ovisacs rather large, oblong oval in form, and slightly divergent. Seminal
receptacle with the anterior part somewhat expanded laterally, posterior part only
slightly produced. Spermatophores attached to the genital opening of quite unusual
size, kidney-shaped and placed close together longitudinally to the axis of the body.

Colour uniformly whitish grey.

Length of adult female 0.90—1.10 mm.

Remarks.—This form ranges among the smaller species of the present
genus, and may readily be recognised by its comparatively short and stout tail,
which character indeed has given rise to the specific name proposed. In the
structural details also it exhibits several well-marked differences from the species
described in the preceding pages.

Occurrence.—I have taken this form occasionally in shallow pools and
ditches near Christiania. It is not very active in its motions, and in this respect
somewhat resembles the next species.

Distribution.—Sweden (Lilljeborg), Bohemia (Schmeil).

28. Cyclops langvidus, G. O. Sars.
(Pl. XXX).
Cyclops langvidus, G. O. Sars, 1. ¢., p. 40.
Specific Characters.—Female. Body moderately slender, with the anterior
division oval in form, greatest width somewhat exceeding half the length and

51

occurring about in the middle. Lateral parts of the penultimate trunk-segment of
the same shape as those of the 2 preceding ones. Last trunk-segment only slightly
produced laterally. Tail of moderate length, with the genital segment rather
large, though evenly contracted behind. Caudal rami almost attaining the length
of the last 3 segments combined, and very slightly divergent; seta of outer edge
somewhat remote from the apex; middle apical sete slender, the inner one some-
what exceeding the tail in length; seta of inner corner extremely small and
rudimentary, that of outer corner normally developed. Anterior antenne about
equal in length to the cephalic segment, and composed of only 16 joints, the
3rd and 4th joints being confluent. Posterior antenne with the terminal joint
‘longer than the penultimate one. Maxillipeds rather short and stout, though
otherwise exhibiting the usual structure. Natatory legs to some extent imperfectly
developed, both rami of Ist pair being only biarticulate, and the inner ramus of 2nd
pair likewise biarticulate, outer ramus of this pair, on the other hand, as also
both rami of the 2 succeeding pairs, distinctly 3-articulate; terminal joint of
outer ramus in these pairs provided outside with 2 spines, inside with 3 sete;
apical spines of inner ramus in 4th pair comparatively short, the inner one being
the longer. Last pair of legs distinctly biarticulate, resembling in structure those
in C. pulchellus, the distal joint being rather slender, sublinear in form, with
the lateral spine attached close to the end. Ovisacs generally of very large size,
reaching in some cases far beyond the caudal rami, and somewhat divergent.
Seminal receptacle with the anterior part transversely elliptical in form, posterior
part very little produced.

Colour uniformly whitish grey.

Length of adult female about 1.00 mm.

Remarks. This form was described by the present author as early as
the year 1863, and has subsequently been also observed by some other authors.
It is chiefly distinguished from the species described in the preceding pages by
the imperfect development of the 2 anterior pairs of natatory legs, agreeing in
this respect with the 2 succeeding species. From the latter it may be readily
recognised by its comparatively larger size, by the greater number of joints in
the anterior antennz, and by the normally developed last pair of legs.

Occurrence.—| have met with this form occasionally in shallow pools and
ditches near Christiania, especially in the spring. The movements of the animal,
when alive, are very slow and are not, as usual, effected by abrupt jumps, but

more resemble an even course through the water, during which the body turns now

52
the right, now the left side upwards. This peculiar mode of movement has indeed
given rise to the specific name proposed.
Distribution.—Sweden (Lilljeborg), Germany (Schmeil), France (Richard).

29. Cyclops diaphanus, Fischer.
(Pl. XXXD).

Cyclops diaphanus, Fischer, Beitriige zur Kenntniss der in der Umgegend von St. Petersburg sich
findenden Cyclopiden (Fortsetzung). Bulletin Soc. Imp. Moscow; Vol. XXVI, p. 93, Pl. II,
figs. 6—12.

Syn.: Cyclops nanus, G. O. Sars.

Fs » minutus, Claus.

Specific Characters.—Female. Body somewhat more slender than in the
preceding species, with the anterior division less dilated, the greatest width
scarcely exceeding half the length. Lateral parts of penultimate trunk-segment
resembling in shape those of the 2 preceding segments. Last trunk-segment very
slightly produced laterally. Genital segment comparatively large and protuberant
below, being longer than it is broad at the base, and gradually contracted behind.
Caudal rami scarcely attaining the length of the last 3 segments combined and
not at all divergent; seta of outer edge at a considerable distance from the apex,
being attached almost in the middle; inner medial seta much longer than the
outer, and attaining almost half the length of the body; seta of inner corner,
as in C. langvidus, very small and rudimentary. Anterior antenne scarcely as
long as the cephalic segment, and composed of only 11 joints. Posterior antenne
and maxillipeds about as in the preceding species. Natatory legs, as in that
species, imperfectly developed, both rami of the Ist pair and the inner one of
the 2nd pair being only biarticulate; rami of the 2 succeeding pairs of normal
structure and comparatively more slender than in C. langvidus; apical spines of
inner ramus in 4th pair rather elongated, the inner one attaining fully the length
of the terminal joint. Last pair of legs extremely small, with the proximal joint
imperfectly defined from the segment, distal joint narrow linear in form, with a
very small lateral spine near the apex. Ovisacs of moderate size and only very
slightly divergent. Seminal receptacle resembling in shape that in C. langvidus.

Body rather pellucid, with a faint yellow or reddish tinge.

Length of adult female 0.70—0.90 mm.

Remarks.—Lilljeborg has pointed out that the species originally described
by the present author as C. nanus, is in reality identical with that recorded by
Fischer at a somewhat earlier date under the name C. diaphanus, and that the

C. minutus of Claus is referable to the same species. Dr. Schmeil, who, how-

Mae)

ever, had not himself had an opportunity of examining the species, placed it, together
with C. gracilis Lilljeborg, m a separate group of Cyclopses (his gracilis-diaphanus
group). This arrangement cannot, however, be accepted. ‘The 2 said species are
in reality very different, though apparently agreeing as to the number of joints
in the anterior antenne and the imperfect development of the last pair of legs.
I am inclined to refer C. gracilis, which, however, I unfortunately have not myself
had an opportunity of examining, to the succeeding genus, Mesocyclops, whereas
the present species is unquestionably a genuine Cyclops, and indeed so closely
allied to C. langvidus, that Dr. Schmeil was inclined to regard my C. nanus, which
as above stated is only a synonym of C. diaphanus, as merely a variety of C.
langvidus, the latter being referred by that author to his “bicuspidatus group”. The
specific distinctness of the present form cannot, however, by rights be disputed,
as it differs from C. langvidus, not only in its much smaller size, but also in the
smaller number of joints in the anterior antennze, the imperfect development of
the last pair of legs, and finally in the shape of the caudal rami.

Oceurrence.—I have only met with this form in a few places near Chri-
stiania, viz., in some shallow grassy pools lying close to the border of a large
lake, the Sognsvand, and apparently left by the reflux of the water in the
lake. A single specimen was also found last summer in Mjosen, near Hamar,
at a depth of about 4 fathoms.

Distribution.—Sweden (Lilljeborg), Germany (Claus), Russia (Fischer).

30. Cyclops abyssicola, Lilljeborg.
(Pl. XXXII).
Cyclops abyssicola, Lilljeborg, Svenska Arterna af SI. Cyclops. Kongl. Sv. Vet. Akad. Handl.
Bd. 35, No. 4, p. 66, Pl. IV, figs. 16—19.

Specific Characters.—Female. Body comparatively short and stout, with
the anterior division regularly oval in outline, greatest width considerably exceed-
ing half the length and occurring in the middle, frontal part narrowly rounded.
Lateral parts of the trunk-segments only slightly prominent and rounded off at
the end. Last trunk-segment very small and scarcely produced laterally. Genital
segment, on the other hand, of unusual size, exceeding in length the 3 succeeding
segments combined, and considerably dilated in front, being conspicuously broader
than the last trunk-segment. Caudal rami not much produced, being scarcely
longer than the last 2 segments combined, and not at all divergent; seta of outer
edge not far from the apex and attached somewhat dorsally; middle apical

sete rather strong and somewhat unequal, the inner one being much the larger

and nearly equalling the tail in length; seta of inner corner very small, that of
the outer about twice as long and spiniform. Anterior antenne short and stout,
not nearly attaining the length of the cephalic segment, and composed of only
10 joints thickly clothed with coarse diverging sete. Posterior antenne likewise
unusually short, with the 3 outer joints nearly equal in length. Mavxillipeds also
comparatively short and stout, especially the anterior ones. Natatory legs, as in
the 2 preceding species, imperfectly developed, both rami of Ist pair and the
inner one of 2nd pair being biarticulate; spines of outer ramus unusually long
and slender, especially those in the Ist pair; seta attached outside the terminal
joint of inner ramus in all the pairs spiniform; apical spines of this joint in 4th
pair rather produced, the inner one being somewhat longer than the outer. Last
pair of legs extremely small and attached to the outer corners of the last trunk-
segment, proximal joint confluent with the segment, distal joint narrow, sublinear
in form, with the lateral spine issuing from the apex itself, immediately inside
the apical seta. Ovisacs, according to Lilljeborg, of small size. Seminal receptacle
rather large, with the anterior part very broad, forming on each side a rounded
expansion, posterior part somewhat produced, linguiform.

Colour whitish, with a faint rosy or violaceous tinge.

Length of adult female 0.75 mm.

Remarks.—Vhis is a very distinct and easily recognisable species, differing
conspicuously in its outward appearance from those described in the preceding
pages, and somewhat recalling certain species of the genus Platycyclops, especially
P. fimbriatus (Fischer). It is, however, a genuine Cyclops, as shown by the struc-
ture of the legs, and in this respect closely approaches the 2 preceding species.

Occurrence.—Some specimens of this pretty form were taken last summer
in Mjosen, near Hamar, from a depth of 4—6 fathoms, muddy bottom. According
to Lilljeborg, it descends in some instances to considerably greater depths, having
been found by that author in one of the Swedish Jakes (Ifsj6) down to 25
fathoms. It was indeed for this reason that the specific name abyssicola was
proposed.

Distribution.—Sweden (Lilljeborg).

31. Cyclops varicans, G. O. Sars.
(Pl. XXXIII).
Cyclops varicans, G. O. Sars, 1. c.. p. 43.

Syn.: Cyclops orientalis, Uljanin.

Specific Characters.— Female. Body not very slender, with the anterior

division oval in form, greatest width somewhat exceeding half the length and

occurring about in the middle. Cephalic segment comparatively large and evenly
rounded in front. Last trunk-segment somewhat produced laterally. Tail only
slightly exceeding half the length of the anterior division; genital segment con-
spicuously dilated in front and gradually narrowed behind. Caudal rami about
the length of the last 2 segments combined and scarcely divergent; seta of outer
edge somewhat remote from the apex, middle apical set rather slender, the inner
one considerably longer than the outer, and about equalling in length the tail
and last trunk-segment combined; seta of inner corner very thin, though consider.
ably longer than that of the outer. Anterior antennz comparatively short, not
attaining the length of the cephalic’ segment, and only composed of 12 joints.
Posterior antenne with the last joint scarcely longer than the penultimate one.
Anterior maxillipeds short and stout, with the claw of the 2nd basal joint almost
straight. Natatory legs with both rami in all the pairs biarticulate, 4th pair, in
the living animal, generally projecting to each side of the trunk; inner ramus
of this pair with both apical spines well developed, the onter one about half
as long as the inner. Last pair of legs with the proximal joint wholly confluent
with the segment, its seta springing off from the lateral corner, distal joint small,
narrow conical in form, and having an extremely minute spinula in the middle
of the inner edge, apical seta rather slender. Ovisacs comparatively large, oblong
in form, and somewhat divergent. Seminal receptacle small, rounded, exserted on
each side to a narrow band-like stripe.

Colour whitish, with a fainte yellow or reddish tinge.

Length of adult female 0.70—0.90 mm.

Remarks.—This species, together with the succeeding one, is included by
Dr. Schmeil in a particular group of Cyclopses (his varicans-bicolor group), chiefly
characterised by the biarticulate rami on all the natatory legs, and the imperfect
development of the last pair of legs. The same characters are also exhibited by
some exotic Cyclopses. Thus, of the several species described by the present
author from the lake Tanganyika, Central Africa, C. attenuatus, C. Cunningtoni
and C. pachycomus belong to this group. The same is also the case with the
Australian species, C. Arnaudi, G. O. Sars. Finally the form recorded by Dr.
Lepeschkin as C. diaphanus, var. dengizica represents another species of the said
group. According to the statement of Dr. Schmeil the C. orientalis of Uljanin is
identical with the present species, and I am also of opinion, that the C. rubellus
of Lilljeborg can hardly be distinguished specifically.

Occurrence.—This form seems to be of rare occurence in our country.
I have only met with it in some grassy ponds near Christiania. The specific

name varicans alludes to the peculiar manner in which the 4th pair of natatory

56 —

legs are borne in the living animal, these legs being constantly extended laterally
to each side of the trunk, without apparently partaking in the movements of the
other pairs.

Distribution. —Sweden (Lilljeborg), Germany (Schmeil), Poland (Lande),
Turkestan (Uljanin), Central Africa (G. O. Sars), New Zealand (G. O. Sars),
North America (Herrick).

32. Cyclops bicolor, G. O. Sars.
(eh xexouy):
Cyclops bicolor, G. O. Sars, 1. ¢., p. 44.
Syn.: Cyclops diaphanus, Rehberg (not Fischer).

Specific Characters.— Female. Body comparatively short and stout, with
the anterior division oval in form, greatest width slightly exceeding half the lenght
and occurring about in the middle. Last trunk-segment less produced laterally
than in C. varicans. Tail rather slender, equalling ?/; of the length of the anterior
division; genital segment only slightly dilated in front and gradually tapered
behind, its anterior parts rather protuberant below. Caudal rami about the length
of the last 2 segments combined and of linear form, being not at all divergent;
seta of outer edge not far from the apex, the 2 middle apical sete remarkably
thick and densely covered with cilia, the imner one only slightly longer than the
outer and much shorter than the tail; seta of inner corner about twice as long
as that of the outer and much thinner. Anterior antenne still shorter than in
C. varicans, only slightly exceeding half the length of the cephalic segment, and
composed of only 11 joints. Posterior antenne with the last joint considerably
longer than the penultimate one. Maxillipeds agreeing in structure with those in
C. varicans. Natatory legs, as in that species, with both rami in all the pairs
biarticulate; 4th pair rather smaller than the preceeding pairs, and having the rami
comparatively narrow, outer apical spine of inner ramus very small and rudimentary,
inner spine long and slender. Last pair of legs still more reduced than in
C. varicans, its proximal joint wholly coalescent with the segment, distal joint
extremely small, without any trace of a lateral spine. Ovisacs of moderate size
and carried closely appressed to the tail. Seminal receptacle transversely ellipti-
cal in form and almost occupying the whole width of the genital segment.

Colour rather peculiar, the anterior division of the body being, as a rule,
nearly colourless, whereas the whole tail and the anterior antenne exhibit a
beautiful golden yellow or orange hue.

Length of adult female scarcely exceeding 0.60 mm.

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WITH 16 AUTOTYPIC PLATES

BERGEN
PUBLISHED aN THE BERGEN MUSEUM

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57

Remarks.—This form, the smallest of all our Cyclopses, has been con-
founded by several authors (Rehberg, Daday, Lande, Richard) with C. diaphanus
Fischer, from which it differs in many essential points, being much more nearly
related to C. varicans. From this latter species it may be easily recognised by
its much smaller size, the shorter and only 11l-articulate anterior antennse, and
the different structure of the caudal sete. finally by the peculiar colouring of the
body when alive.

Occurrence.

I have only found this form quite occasionally in small
grassy ponds near Christiania. In spite of its small size, it may be readily
detected, owing to its peculiar and beautiful colour, which character indeed has
given rise to the specific name proposed.

Distribution.—Sweden (Lilljeborg), Germany (Schmeil), Hungary (Daday),
Poland (Lande), France (Richard).

Gen. 13. Mesoeyelops, G. 0. Sars, n.

Generic Characters.—-Body more or less slender, with the anterior division
cenerally rather tumid, the posterior very slender. Epimeral parts of the trunk-
segments scarcely prominent laterally and, as a rule, not visible in the dorsal
aspect of the animal. Last trunk-segment very small, not produced laterally.
Genital segment in female rather elongated and very little dilated in front. Caudal
rami of moderate length or very short, with all the apical sete generally well deve-
loped. Anterior antenne slender and elongated, generally 17-articulate. Posterior
antennze likewise slender, with the apical sete long and curved. Maxillipeds
rather fully developed. Natatory legs, as a rule, with both rami 3-articulate;
terminal joint of outer ramus in all pairs with only 2 spines outside, its inner
edge carrying in the Ist pair 2, in the other pairs 3 sete; terminal joint of inner
ramus unusually prolonged, especially in the posterior pairs. Last pair of legs
very small and generally biarticulate, distal joint carrying 2 slender subequal sete.
Seminal receptacle in all the species of a very characteristic form, anterior part
short, bilobular, posterior greatly prolonged, tongue-shaped.

Remarks.—This new genus answers to the group of Cyclopses distinguished
by Dr. Schmeil as the “Leuckarti group”. The species included in this group
differ conspicuously in their external appearance from the more typical Cyclopses
described in the preceding pages, and more resemble those belonging to the next

genus, Pachycyclops, with which they also agree in the unusually slender form of

8 — Crustacea.

58

both pairs of antenne. In the structure of the natatory legs, the unusual
prolongation of the terminal joint of the inner ramus is rather characteristic. The
last pair of legs are also distinguished by the presence on the distal joint of 2
slender, subequal seta, the inner one replacing the short lateral spine found in
the species of Cyclops (sens. strict.). Finally, the very characteristic form of the
seminal receptacle may be here mentioned.

To the fauna of Norway belong 4 well-defined species, to be described
below, and also a number of exotic species may be adduced to the same genus.
Thus it is evident that the 2 African species, C. emimi Mrazek and C. neglectus
G. O. Sars, recorded by the present author in his paper on the Copepoda of the
Tanganyika Expedition, are referable to this genus, as is unquestionably the case
with the North American species, C. edax Forbes, perhaps also with the South
American species, C. spinifer Daday. I am likewise of opinion that C. gracilis
Lilljeborg must be placed within the present genus, in spite of the reduction of
the number of joints in the anterior antenne, and the imperfect development of
the legs, as this form otherwise has an unmistakable resemblance to the species

here under consideration.

33. Mesoeyclops obsoletus (Koch).
(Pl. XXXV).
Cyclops obsoletus, Koch, 1, ce. Heft 21, Tab. 5.
Syn: Cyclops Leuckarti, Claus.
. x simplex, Poggenpol.
- Scourfieldi, Brady.

Specific Characters—Female. Body moderately slender, with the anterior
division regularly elliptical in outline, greatest width slightly exceeding half the
length and occurring about in the middle. Cephalic segment very large, almost
twice the length of the 4 succeeding segments combined. Last trunk-segment
very small. ‘Tail slender, exceeding in length °/; of the anterior division; genital
segment long and narrow, fully attainmg the length of the 3 succeeding segments
combined, and almost cylindrical in form. Caudal rami of moderate length, though
scarcely as long as the Jast 2 segments combined, and only slightly divergent;
seta of outer edge rather far from the apex, being attached a little behind the
middle; apical setee comparatively slender and elongated, the inner mediate one
attaining the length of the tail, seta of outer corner rather produced, though
scarcely half as long as that of the inner. Anterior antenne long and slender,
reaching, when reflexed, almost to the end of the 3rd segment, outer joints rather

narrow and bordered by a delicate hyaline rib, which on the last joint, at some

59

distance from the end, exhibits a very conspicuous semilunar incision. Posterior
antenne likewise unusually slender, with the terminal joint long and narrow.
Anterior maxillipeds with the posterior edge of the basal part distinctly crenulated.
Posterior pair of maxillipeds of the usual structure. Natatory legs comparatively
slender, spines of outer ramus rather coarse, the distal outer spine of the terminal
joint apparently issuing from the tip itself, outer edge of the joints very finely
spinulose; terminal joint of inner ramus in all pairs unusually prolonged, being
fully as long as the other 2 joints combined, sets of inner edge in the 3 posterior
pairs rather far from the apex and some of them reduced in size; apical spines of
this ramus in 4th pair almost equal-sized; connecting plate of same pair produced
bebind, on each side, to an acute projection. Last pair of legs with the distal joint
rather narrow, both sete very slender and elongated, the inner one somewhat remote
from the tip. Ovisacs of moderate size and somewhat diverging. Seminal receptacie
exhibiting the form characteristic of the genus, anterior lobes somewhat exserted at
the ends, posterior part extending almost to the end of the genital segment.

Colour generally pale yellow, with a more or less distinct bluish
green tinge.

Length of adult female 1.00—1.30 mm.

Remarks.—I have no doubt that the C. obsoletus of Koch is in reality this
species. The figure he gives is rather characteristic, and cannot properly be
adduced to any other species. As the specific name proposed by Koch is much
older than that given to the species by Claus, it must be retained for the present
form. The C. Scourfieldi of Brady is the same species, and according to Dr.
Schmeil, C. sumplex Poggenpol also is to be regarded as a synonym.

Occurrence.

This is one of our commonest Cyclopids, occurring very
abundantly both in small ponds and ditches and in larger lakes. In the latter
it lives as a true limnetic form, being found everywhere near the surface of the
water together with other limnetic animals.

Distribution.—Throughout Europe, central and northern parts of Asia,
Ceylon, central and southern parts of Africa, North America, Brazil, Patagonia,

Australia. The cosmopolitan distribution of this species is very remarkable.

34. Mesocyeclops oithonoides, G. O. Sars.
(Pl. XXXVI).

Cyclops oithonoides, G. O. Sars, 1. c. p. 32,
Syn: Cyclops hyalinus, Rehberg.
Specific Characters.— Female. Body very slender, with the anterior division

narrow oblong in outline, greatest width not nearly attaining half the length and

60

occurring somewhat in front of the middle. Cephalic segment somewhat longer
than the 4 succeeding segments combined. Last trunk-segment very small, with
the lateral parts obtusely rounded. ‘Tail attaining */, of the length of the anterior
division; genital segment about equalling in length the 2 succeeding segments
combined, and almost cylindrical in form. Caudal rami of moderate length and
somewhat diverging, seta of outer edge placed almost in the middle; apical sete
comparatively shorter than in the preceding species, the inner mediate one
scarcely exceeding half the length of the tail; seta of imner corner fully 3 times
as long as that of the outer, and only slightly shorter than the outer mediate
one; dorsal bristle unusually slender. Anterior antenne much elongated, reaching,
when reflexed, even somewhat beyond the 3rd segment, and clothed with rather
slender seta, lateral ribs of outer joints very slight and quite simple. Posterior
antennze with the terminal joint less narrow than in M. obsoletus, and scarcely
longer than the penultimate one. Both pairs of mavxillipeds largely developed,
the anterior ones without any crenulation of the hind edge. Natatory legs with
the rami very slender; apical spine of outer ramus in 2nd to 4th pairs much
elongated and coarsely denticulated; terminal joint of inner ramus shorter than
the other 2 combined; apical spines of this ramus in 4th pair very unequal, the
outer one being extremely small, the inner very much elongated and generally
somewhat bent inwards; connecting lamella of same pair with the projections of
the hind edge obtuse at the tip. Last pair of legs resembling in shape those in
M. obsoletus, but having the apical sete comparatively shorter. Ovisacs, as a
rule, small, rounded, and containing only a very limited number of ova. Seminal
receptacle resembling that of the preceding species, though having the anterior
lobes more obtuse and the posterior part narrower. _

Body highly pellucid, with a very faint yellow tinge.

Length of adult female scarcely exceeding 0.90 mm.

Remarks.—This form is easily recognisable by its very slender and narrow
body and the long spreading sete clothing the anterior antenne, these characters,
as also its habits, somewhat recalling the slender pelagic species of the marine
genus Oithona. It was indeed in allusion to this resemblance that the specific name,
oithonoides, was proposed by the present author. The Cyclops hyalinus of Rehberg
is unquestionably this species, as is easily seen from the figure he gives of the furca.

Occurrence.—I have found this form not infrequently in several of our larger
lakes, more rarely in small tarns. In habits it is a true limnetic form, keeping
itself always freely suspended in the water, and generally near the surface.

Distribution.—Sweden (Lilljeborg), Germany (Schmeil), central part of
Asia (G. O. Sars), North America (Herrick).

6 |

35. Mesocyclops crassus (Fischer).
(Pl. XXXVI).
Cyclops crassus, Fischer, Beitrige zur Kenntniss der Cyclopiden (Fortsetzung). Bulletin Soc. Imp.
Nat. Moscou, Tome XXVI, Part 1, p. 92, Pl. III, figs. 13—18.
Syn: Cyclops oithonoides, var. hyalina, Schmeil.
5 2 hyalinus, Lande, Richard, Lilljeborg (not Rehberg).

Specific Characters.—Female. Body rather short and stout, with the
anterior division oval in form, greatest width attaining fully half the length and
occurring in the middle. Last trunk-segment small, though somewhat broader than
in the 2 preceding species. ‘ail scarcely exceeding half the length of the
anterior division; genital segment about the length of the 3 succeeding segments
combined, and somewhat tapered behind. Caudal rami unusually short and thick,
scarcely exceeding in length the anal segment, and somewhat divergent; seta of
outer edge very small and attached not far from the apex; apical sete of mode-
rate length, the inner mediate one almost as long as the tail; seta of inner corner
more than 3 times as long as that of the outer, and not much shorter than the
outer mediate one. Anterior antenne somewhat less slender than in the 2 pre-
ceding species, reaching, when reflexed, about to the end of the 2nd segment,
lateral rib of the outer joints very slight. Posterior antenne nearly as in
M. oithonoides. Maxillipeds, however, comparatively smaller. Natatory legs
with the rami less slender and the apical spines shorter; those of inner ramus
in 4th pair less unequal, the inner one being scarcely more than twice as long as
the outer and much shorter than the terminal joint of the ramus; connecting
lamella of this pair with the projections of the hind edge coarsely dentate.
Last pair of legs resembling in shape those in JM. oithonoides, though having
the distal joint somewhat smaller and the apical sete comparatively shorter.
Ovisacs rounded oval in form and generally containing only a limited number
of ova. Seminal receptacle about as in AZ. oithonowles.

Body very pellucid, with a faint yellowish tinge.

Length of adult female about 0.80 mm.

Remarks.—Vhe identity of the above-described form with Fischer’s
Cyclops crassus seems to me evident. It has erroneously been identified by
Dr. Schmeil and several other authors with O. hyalinus Rehberg, which, as
stated above, is unquestionably a typical JZ. oithonoides. From the latter species
it is at once distinguished by its much shorter and stouter body, and by the unu-
sually short and thick caudal rami, thus fully deserving the specific name pro-
posed for it by Fischer. In these respects it much more resembles the African
species, M. neglectus G. O. Sars, which however differs in the much shorter

innermost caudal seta.

62

Occurrence.—I have met with this species not unfrequently in the lake
Vansj@ near Moss, where it lives as a true limnetic form. I have also found it
occasionally in wide expanses of the river Glommen, at Nipen.

Distribution.—Sweden (Lilleborg), Germany (Schmeil), Poland (Lande),
France (Richard), Russia (Fischer), Cape of Good Hope (G. O. Sars).

36. Mesocyclops Dybowskyi (Lande).
(Pl. XXXVIII).

Cyclops Dybowskyi, A, Lande, Materyaly do Fauny Scorupiakow Widlonogish, Copepoda, p. 57,
Pl. XVII, figs. 51—59.
Syn: Cyclops crassus, Lilljebore (not Fischer).

Specific Characters.— Female. Body somewhat less robust than in M,
crassus, with the anterior division regularly oval in outline, greatest width about
half the length and occurring somewhat in front of the middle. Last trunk-
segment about as in the preceding species. ‘Tail considerably exceeding half the
length of the anterior division; genital segment about the length of the 3 suc-
ceeding ones combined, and gradually tapered behind. Caudal rami more pro-
duced than in MM. crassus, considerably exceeding in length the anal segment,
and only slightly divergent; seta of outer edge comparatively small and attached
at a short distance from the end; apical sete not much elongated, the inner
mediate one not nearly attaining the length of the tail; seta of inner corner
much shorter than in the 3 preceding species, being only slightly longer than
that of the outer corner and scarcely half as long as the outer mediate one,
dorsal bristle not particularly slender. Anterior antenne of moderate length,
reaching, when reflexed, about to the end of the 2nd segment. Posterior antennze
and maxillipeds about as in J. crassus. Natatory legs also on the whole rather
similar; apical spines of inner ramus in 4th pair, however, distinctly different,
the outer spine being considerably larger than the inner. Last pair of legs
with the distal joint comparatively thicker than in the other species and having
the apical sete rather short. Ovisacs of mederate size, oval in shape, and rather
divergent. Seminal receptacle with the anterior lobes distinctly recurved. Sper-
matophores attached to the genital opening narrow oblong in form and diverging
obliquely behind.

Colour rather peculiar, the body being, as a rule, tinged with a dark
bluish or brownish violet hue.

Length of adult female about 0.90 mm.

Remarks.—This form, first described by A. Lande under the above

specific name, has been erroneously identified by Lilljeborg with Cyclops crassus

Fischer, which, as stated above, is the form described by him as C. hyalinus.
Though nearly allied to that species, it may easily be distinguished by the somewhat
different shape of the caudal rami, and more particularly by the comparatively
short innermost apical seta. In the living state it is moreover at once recognised
by the peculiar colour of the body.

Occurrence.—I have met with this form only quite occasionally in some
small lagunes at the border of the lake Wstensjo near Christiania, and also in
wide expanses of the river Glommen, at Nipen.

Distribution.—Sweden (Lilljeborg), Germany (Schmeil), Poland (Lande).

37. Mesocyelops gracilis (Lilljeborg).
(PIS XOEXTX):
~ Cyclops gracilis, Lilljeborg, De crustaceis ex ordinibus tribus in Scania occurrentibus, Appendix,
p. 208.

Specific Characters.— Female. Body very slender, resembling in outward
appearance that of MM. oithonoides, the anterior division being narrow oblong in
outline and contracted behind, with the greatest width quite in front. Last trunk-
segment very small, with the lateral parts rounded off. Tail slender, equalling
in length about ?/; of the anterior division; genital segment attaining the length
of the 3 remaining segments combined, and slightly tapered behind. Caudal
rami somewhat longer than the anal segment and slightly divergent; seta of outer
edge attached in the middle; apical sets comparatively short, the inner mediate
one scarcely exceeding half the length of the tail; seta of inner corner only
slightly longer than that of the outer, and scarcely half as long as the outer
mediate one; dorsal bristle of moderate length. Anterior antenne long and
slender, reaching, when reflexed, to about the middle of the 3rd segment, and
composed of only 11 joints clothed with very long, diverging, partly ciliated
sete. Posterior antenne likewise comparatively slender, with the terminal joint
longer than the penultimate one, lateral bristles of the latter joint reduced in
number. Maxillipeds rather fully developed resembling in structure those in the
other species of the present genus. Natatory legs, on the other hand, imper-
fectly developed, the rami in all of them being composed of only 2 joints; Ist
joint of outer ramus in 4th pair without any seta imside; apical spines of inner
ramus in same pair very unequal, the outer one being quite rudimentary, the
inner long and slender. Last pair of legs likewise imperfectly developed, the
proximal joint being quite confluent with the segment, distal joint extremely small,
rod-like, and carrying on the tip 2 very unequal sete, the inner one being quite

rudimentary. Ovisacs comparatively small and rounded oval in shape, each con-

64

taining only a very limited number of ova. Seminal receptacle of quite a similar
shape to that in the other species of the present genus, the anterior part being
bilobular, the posterior greatly produced tongue-shaped.

Colour, according to Lilljeborg, dark brownish, or light greyish brown.

Length of adult female about 0.80 mm.

Remarks.—Through the kindness of Prof. Wirén of the Upsala University
I have had the opportunity of examining this interesting species, and have thereby
found my above-indicated suggestion about the systematic position of this form
fully confirmed. In spite of the reduction of the number of joints in the anterior
antenne and the imperfect development of the legs, it must, in reality, be
referred to the present genus, with which it otherwise agrees perfectly. Its
resemblance, indeed, both as regards size and general appearance, to one of the
above-described species, viz., I. oithonoides, is so perplexing, that at first sight it -
might even easily be confounded with that form. It will be found that the above-
mentioned differences in the structure of the anterior antenne and the legs are
quite analogous to those observed in certain species of the genus Cyclops (sens.
strict.), and are merely due to a retarded development of these appendages.

Occurrence.—This form, it is true, has not yet been observed within the
limits of our country; but, as it occurs in the neighbouring parts of Sweden, it
is very probable that, on a closer investigation, it will in reality be found in some
place or other in the south-eastern part of the country.

Distribution.—Sweden (Liiljeborg), Germany (Schmeil), Poland (Lande).

Gen. Pachyceyclops, G. O. Sars, n.

Generic Characters.—Body robust, with the anterior division much dilated
and boldly vaulted above. Epimeral parts of the trunk-segments not produced
laterally; last segment very small. Tail not very slender, with the genital
segment of moderate size and only slightly dilated in front. Caudal rami com-
paratively short, but with the apical sete well developed. Anterior antenne long
and slender, 17-articulate. Posterior antenne likewise slender, with long curved
apical sete. Maxillipeds comparatively shorter and stouter than in Mesocyclops.
Natatory legs normally developed, with both rami 3-articulate, terminal joint of
outer ramus in Ist to 3rd pairs with 3 spines outside, in 4th pair with only 2
such spines, inner edge of this joint carrying in Ist pair 3, in the succeeding

pairs 4 sete. Last pair of legs biarticulate, proximal joint more or less pro-

65

longed and carrying at the outer distal corner the usual slender bristle, distal
joint short, lamelliform, constricted at the base and trilobate at the end, carrying
2 unequal spines and an intermediate slender seta attached to a conical
prominence of the joint. Seminal receptacle with the posterior part more or less
distinctly bipartite.

Remarks.—This genus answers to the “fuscus-albidus group” of Dr. Schmeil,
and comprises a limited number of species, which are all distinguished by their
robust body, the tumid and boldly vaulted anterior division, and the very slender and
elongated anterior antennee. Of anatomical details may be particularly mentioned
the characteristic structure of the last pair of legs, which is very unlike that in
any of the other known groups of Cyclopses. 3 species belonging to this genus
will be described below, and I am inclined to believe, that also the North-American
species, Cyclops ater Herrick, may be referable to this genus, though the last
pair of legs are said to be uniarticulate.

38. Pachycyelops signatus (Koch).
(Pl. XL).

Cyclops signatus, Koch, |. c. Heft 21, Tab. 8.
Syn: Cyclops qvadricornis fuscus, Jurine.
‘s coronatus, Claus.
3 is fuscus, Schmeil.

Specific Characters.— Female: Anterior division of body broadly ovate in
outline, greatest width about equalling half the length and occurring in front of
the middle. Cephalic segment large and tumid, with the frontal edge narrowly
truncated. Last trunk-segment very small and sharply defined from the preceding
one. ‘Tail comparatively short, scarcely attaining half the length of the anterior
division; genital segment about the length of the 3 succeeding segments combined,
and almost cylindrical in form. Caudal rami rather short, though somewhat
longer than the anal segment, and slightly divergent, inner edge finely ciliated;
seta of outer edge very small and attached close to the end; apical sete densely
plumose and rather spreading, the inner mediate one exceeding the tail in length;
seta of outer corner rather elongate, though shorter than that of the inner corner.
Anterior antenne very slender and attenuated, reaching, when reflexed, to the
end of the 3rd segment, distal edge of the 8th, 9th, 11th, 12th and 13th joints
distinctly denticulated, the 3 outermost joints very narrow and exhibiting along
the upper face a delicate hyaline rib, which on the proximal part of the last
joint is divided into 8 strong serrations. Posterior antennw unusually slender,
with the penultimate joint long and narrow, attaining fully the length of the

9 — Crustacea.

66

terminal one, antepenultimate joint comparatively short and broad, oval in form,
and coarsely denticulated on the hind edge; 2 of the apical sete much more
elongated than the others. Anterior maxillipeds strongly built, with the claw and
spines issuing from the distal part very coarse and denticulated inside. Posterior
maxillipeds, on the other hand, comparatively slender, with the first 2 joints
narrower than usual. Natatory legs exhibiting the structure characteristic of the
genus, rami comparatively slender, especially those of 4th pair; apical spines of
inner ramus in this pair rather unequal, the outer one being much the larger.
Last pair of legs with the proximal joint oblong quadrangular in form, and densely
clothed inside with small spikes, distal joint somewhat shorter and much narrower,
spine of inner edge almost twice as long as that of the outer, both being com-
paratively slender and finely denticulated; apical seta still longer and clothed with
scattered cilia. Ovisacs comparatively large and borne closely appressed to the
body, so as partly to obtect the dorsal face of the tail. Seminal receptacle with
the posterior part rather produced and narrowly cleft in the middle.

Body of a more or less dark fuscous colour, with a greenish or bluish
tinge and variegated with still darker irregular shadows; caudal rami and ad-
joming part of tail bluish green, and also the anterior antenne and the legs
tinged with the same colour, ova in the ovisacs generally of a very dark brown hue.

Length of adult female amounting to 2.50 mm.

Remarks. —This is one of our largest and most beautiful Cyclopids, being
easily recognisable from most other species. The Cyplops qvadricornis fuscus of
Jurine is in all probability referable to the present species; but, as noted before,
I find it scarcely admissible to appropriate the varietal names appended by that
author to his species C. qvadricornis as true specific designations. That the
Cyplops signatus of Koch is this species, is quite certain, and this has also been
admitted by all authors. The name C. coronatus proposed by Claus for this
species is of much later date, and must of course cede to that of Koch.

Occurrence.—I have met with this handsome species chiefly at the borders
of large lakes or in lagunes and ponds left by the reflux of the water in these
lakes. In habits, like the other species of the present genus, it is a true bottom-
form, being frequently seen clinging to some object on the ground or to the
plants growing upon it. When disturbed it darts away with a sudden bound,
and so rapidly that it becomes a matter of great difficulty to catch it by the
aid of an ordinary dipping-tube.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil),
Poland (Lande), France (Richard), Central Asia (G. O. Sars), North America
(Herrick).

67

39. Pachyeyelops bistriatus (Koch).
(Pl. XLI).
Cyclops bistriatus, Koch, |. c. Heft 21, Tab. 7.
Syn: Cyclops distinctus, Richard.

x es gracilicornis, Lande.

Specific Characters.—Female. Anterior division of body regularly oval
in outline, greatest width somewhat exceeding half the length and occurring about
in the middle. Tail comparatively short, scarcely attaining half the length of the
anterior division; genital segment somewhat shorter and broader than in P. sig-
natus. Caudal rami a little more produced, though scarcely attaining the length
of the last 2 segments combined; apical sete rather spreading and exhibiting
nearly the same mutual relation in length as in the preceding species. Anterior
antenne still more slender and elongated than in that species, reaching, when
reflexed, even to the end of the 4th segment, lateral rib of the outer joints incon-
spicuous. Posterior antennz of normal structure, the penultimate joint being much
shorter than the terminal one and also distinctly thicker; apical sete, as usual,
gradually increasing in length inwards. Both pairs of maxillipeds conspicuously
smaller than in the preceding species. Natatory legs with the rami compara-
tively broader; terminal joint of inner ramus in 4th pair somewhat curved in the
middle, and having the apical spines less unequal, the inner one conspicuously
bent inwards. Last pair of legs resembling in structure those in the preceding
species, though having the distal joint comparatively larger in proportion to the
proximal one. Ovisacs rather large and slightly divergent. Seminal receptacle
with the posterior part rather produced and very conspicuously bipartite.

Body of a dark blue colour, with the anterior part of the cephalic seg-
ment somewhat lighter.

Length of adult female about 2.20 mm.

Remarks.—I think I am right in identifying the above-described form
with Cyclops bistriatus of Koch. The figure given by Koch applies fairly well
to the present form, and also his notes about the colour agree. In any case it
is evident that the figure represents a true Pachycyclops, and as the 2 other
species are both very recognisably figured by that author, the said figure cannot
refer to any other species than the one here under discussion. As Koch’s name
has the precedence both to that given to the species by Dr. Richard, and to that
proposed by A. Lande, it ought to be retained for the present species, though it
is somewhat inappropriate, being apparently derived from the anteriorly some-
what divergent dark ovarial tubes shining through the body. Dr. Schmeil at

first opined that this form was merely a hybrid between the 2 other species: but

68

he has subsequently recognised its specific distinctness. As to its relation to the
2 other species, I think that it comes nearer to P. signatus than to P. annulicornis.

Occurrence.

The only place where I have as yet met with this form, is
in a small tarn near Christiansand. It occurred here, together with other Ento-
mostraca, near the bank on a muddy bottom covered with coarse gravel. All
the specimens observed were of a very dark bluish colour and in their whole
behaviour exhibited so great a resemblance to P. signatus, that at that time I
regarded them as merely belonging to a variety of that species, for which reason
I only made a coloured drawing of one of them, omitting to preserve the speci-
mens for further examination. The figures here given are from Swedish speci-
mens kindly sent to me by Prof. Wirén of the Upsala University.

Distribution.—Sweden (Lilljeborg), Germany (Schmeil), France (Richard),
Poland (Lande).

40. Pachyeyelops annulicornis (Koch).
(PI. XLIT).
Cyclops annulicornis, Koch, |. c. Heft 21, Tab. 6.
Syn: Cyclops qvadricornis albidus, Jurine.
tenwicornis, Claus.

FS albidus, Schmeil.

gyrinus, Forbes.

"

Specific Characters.—Female. Anterior division of body broadly oval in
outline, greatest width exceeding half the length and occurring somewhat in front
of the middle. Tail comparatively more slender than in the 2 preceding species,
somewhat exceeding half the length of the anterior division; genital segment of
about the same shape as in P. signatus. Caudal rami comparatively short and only
slightly diverging, inner edge scarcely ciliated; apical sete less densely plumose
and less spreading than in the 2 preceding species, the inner mediate one almost
attaining half the length of the body; seta of outer corner comparatively short,
scarcely exceeding in length '/; of that of the inner corner. Anterior antenne
long and slender, reaching, when reflexed, beyond the 3rd segment, outer joints
very narrow and exhibiting a well-defined lateral rib, which is quite smooth through-
out, and projects at the end in a small lappet. Posterior antenne with the
terminal joint much longer and narrower than the penultimate one. Maxillipeds
about as in P. bistriatus. Natatory legs likewise very similar; terminal joint
of inner ramus in 4th pair, however, distinguished by the quite rudimentary con-
dition of the distal seta of inner edge; apical spines of this ramus shghtly une-
qual, the outer one being the larger. Last pair of legs of almost exactly the same

shape as in P. signatus, the distal joint being conspicuously smaller than the

69

proximal one. Ovisacs generally narrow oblong or fusiform in shape and, as a
rule, diverging greatly, im some cases, however, more appressed to the body.
Seminal receptacle with the posterior part very little produced and slightly emarg-
inated in the middle. Spermatophores attached to the genital orifice lageniform
and closely juxtaposed.

Body of a clear yellowish grey colour, with a more or less distinct
olivaceous tinge, and variegated with dark transverse bands at the end of some
of the segments, as also across the cephalic part; anterior antenne generally
with 2 very conspicuous dark bands, the one occupying the 2nd and 3rd _ joints,
the other the 10th and 11th joints.

Length of adult female about 1.80 mm.

Remarks.—This form has generally been recorded by recent authors under
the name of Cyclops albidus Jurine, a name which is very little significant, as
the present species in most cases exhibits a rather conspicuous colouring of the
body. For the reason noted above the name ought also to be rejected, and to
be replaced by that proposed by Koch, which has the precedence to the name
tenuicormis given to the species by Claus. The Cyclops gyrinus of Forbes is
unquestionably this species, and is not, as opined by Dr. Schmeil, identieal with
C. distinctus Richard.

The present species is nearly allied to the 2 preceding ones, but is of
smaller size, and moreover easily recognisable from them by the shortness of
the outermost caudal seta. The manner in which the ovisacs are born is also
very characteristic, though in some cases specimens are found in which they are
more appressed to the body, a circumstance which at first led me to the erro-
neous opinion that these specimens might belong to a different species.

Occurrence.—This is one of our commonest Cyclopids, being found both
in small ponds and ditches and in large lakes. In the latter it not only occurs
at the borders, but descends to rather considerable depths. In the lake Mjosen
I have even taken it in great numbers down to 50 fathoms together with
Cyclops vulgaris.

Distribution.—Throughout Europe, northern part of Asia, Central Africa,
Australia, North and South America, Hawaii Islands. he distribution of this

form is accordingly almost cosmopolitan.

Gen. 15. Leptoeyclops, G. 0. Sars, n.

Generic Characters.—Body more or less slender, with the 2 chief divisions
very sharply defined. Epimeral parts of the trunk-segments, as a rule, distinctly
prominent laterally, especially those of penultimate segment, though rounded at
the extremities. Last trunk-segment short and broad, being produced on each
side to a narrowly rounded and densely hairy lobe, somewhat impinging upon
the base of the genital segment. ‘Tail very slender and narrow, with the genital
segment comparatively short and abruptly contracted immediately behind the
base. Caudal rami more or less prolonged, and in most cases exhibiting along
the outer edge a delicate denticulation; seta of this edge small and not far from
the end; middle apical sete slender and elongated, being, as a rule, clothed on
the proximal part with scattered coarse hairs; seta of inner corner of incon-
siderable length and very thin, that of the outer corner more or less spiniform.
Anterior antenne in all the known species composed of 12 joints, the outer ones
generally very slender and narrow. Posterior antenne and oral parts on the
whole of normal structure. Natatory legs well developed, with 3-articulate rami;
Ist pair, as usual, the smallest, and having the 2nd basal joint conically pro-
duced at the inner corner and provided with a long deflexed spine; armature of
the rami as in the genus Pachycyclops. Last pair of legs very small, each
forming a simple somewhat trilobate lamella armed inside with a denticulated
spine, outside and at the conically exserted tip with a slender seta. Ovisacs
generally oval fusiform in shape. Seminal receptacle with the posterior part
not produced, forming 2 transverse bands defined in the middle by a slight
emargination.

Remarks.—Vhe type of this genus is the species generally described
under the name of Cyclops serrulatus Fischer, with which Dr. Schmeil has con-
nected another rather diviating form, C. prasimus Fischer, to form a particular
group of Cyclopses, viz., his “serrulatus-prasinus group”. The most prominent
character distinguishing this genus from the 3 preceding ones, is undoubtedly the
very different structure of the last pair of legs. Several other characters common
to the greater number of the species comprised within this genus may also be
adduced, and are shortly enumerated in the above diagnosis. The genus seems
to be very rich in species; but most of these are so closely related to each
other, that they can be distinguished only by a careful examination, and for
this reason they have been regarded by most earlier authors as only varieties

of one and the same species, viz., C. serrulatus of Fischer. In tbe following

71

pages 5 Norwegian species belonging to this genus will be described. T'o these
may be added a considerable number of exotic species. I have for instance recorded
no less than 7 species from the Central African lake, Tanganyika, and another
well-defined African species is known to me from Cape Colony. Moreover
the North-American species, Cyclops elegans Herrick and C. pectinifer Cragin,
unquestionably belong to the same genus, and also 2 other, apparently new

species from the same part of the world have been examined by me.

41. Leptocyelops agilis, (Koch).
(PI. XLII).
Cyclops agilis, Koch, 1. c. Heft 21, Tab. 3.
Syn: Cyclops serrulatus. Fischer.
5 of varius, var. brachyura, Lilljebore.

Specific Characters.— Female. Body moderately slender, with the anterior
division oval in outline, greatest width somewhat exceeding half the length and
occurring in the middle. ‘Tail slender, about equalling in length */; of the anterior
division; genital segment scarcely longer than the 2 succeeding segments com-
bined and considerably dilated at the base. Caudal rami generally not much
prolonged, equalling about the length of the last 2 segments combined, and
slightly bent outwards at the ends, outer edge finely denticulated throughout;
seta of this edge very small and attached near the end somewhat dorsally ;
middle apical sete rather slender and, as usual, clothed in their proximal parts
with scattered coarse hairs, the inner one about equalling half the length of the
body, the outer considerably shorter; seta of inner corner scarcely longer than
that of the outer, which is much coarser, spiniform. Anterior antenne long and
slender, reaching, when reflexed, to the end of the 2nd segment, the 3 outer
joints very narrow and bordered by a hyaline rib, which is quite smooth through-
out. Posterior antenne with the terminal joint scarcely longer than the penulti-
mate one. Anterior maxillipeds comparatively short and stout, with the sub-
division of the Ist basal segment indistinct. Posterior maxillipeds likewise short,
with the outer 2 joints imperfectly defined and the sete issuing from them in
front stout and curved against each other. Natatory legs exhibiting the structure
characteristic of the genus; apical spines of inner ramus in 4th pair of moderate
size, the inner one somewhat longer and more slender than the outer. Last
pair of legs with the spine of the inner edge very large and coarsely dentate.
Ovisacs oval fusiform in shape and slightly divergent, each containing a rather
limited number of ova. Seminal receptacle with the anterior part transversely
elliptical in form and slightly emarginated anteriorly.

72

Colour more or less dark olivaceous, with a greenish tinge; genital
segment and bases of the caudal rami generally ochraceous.

Length of adult female scarcely exceeding 1 mm.

Remarks.—This appears to be the species that has been observed by
most authors, and to which the name Cyclops serrulatus Fischer has generally
been applied. It seems evident to me, indeed, that the figures given by
Fischer are referable to the present species; but, as the name agilis proposed
by Koch is of much earlier date, it must be retained for the species. Lilljeborg
has applied the name serrulatus to a different species, which will be described
below as L. Lilljeborgi, whereas he has given to the present species a new name,
viz., Cyclops varius. The latter species he again divides into 3 varieties, viz.,
C. speratus, C. proximus and C. brachyurus. The first of these supposed varieties
I regard as a distinct species, whereas the other 2 must be combined within the
species here under consideration, The C. proximus does not differ from the
typical form (C. brachyurus) except in the somewhat longer caudal rami.

Occurrence.—This is a very common Cyclopid, being found everywhere
in small ponds and ditches, as also at the margin cf large lakes. It is a very
active little creature, moving about with considerable speed, and thus fully
deserving the specific name given to it by Koch. Like the other species of the
present genus, it is however a true bottom-form, keeping constantly near the
ground, and scarcely ever being met with in company with the true lim-
netic species.

Distribution.—Throughout Europe, central and northern parts of Asia,
Algeria, Azores, Polar island north of Grinnell Land (2nd Fram Exped.), North

America, Australia.

42. Leptocyclops speratus, (Lilljeborg).
(Pl. XLIV).

Cyclops varius, var. sperata, Liljeborg, Synopsis specierum generis Cyclops, p. 88,
Pl. V, figs. 12—15.

Specific Characters.—Female. Rather like the preceding species, but of
much larger size and somewhat more slender form of body. Caudal rami
considerably prolonged, attaining almost the length of the last 3 segments com-
bined, and closely approximate throughout, not being at all divergent, outer edge
nearly smooth, or with only very slight traces of denticles in its posterior part;
middle apical sete of the usual structure, seta of inner corner considerably
longer than the spine of the outer. Anterior antenne very slender, reaching,

when reflexed, even beyond the 2nd segment, outer joints with a_ distinct

aes

lateral rib, which, as in the preceding species, is quite smooth. Posterior
antennze and anterior maxillipeds about as in that species. Posterior maxillipeds
with the last 2 joints well defined. Natatory legs comparatively more strongly
built than in the type species, with the rami broader; apical spines of inner
ramus in 4th pair rather strong, the inner one being the longer. Last pair of
legs somewhat more produced in relation to the width, and having the spine of
the inner edge still larger, with very coarse denticles on both edges. Ovisacs
comparatively large and considerably divergent. Seminal receptacle with the
anterior part evenly convex in front.

Colour light olivaceous or yellowish grey.

Length of adult female 1.20 to 1.50 mm.

Remarks.—This form, as stated above, was considered by Lilljeborg as
merely a variety of his species Cyclops varius (= C. agilis Koch). I think, how-
ever that it is entitled to be ranged as a distinct species, as it differs not
only in its much larger size, but also in some structural details mentioned in the
above diagnosis.

Occurrence.—I have hitherto only met with this form in 2 localities, viz.,
in some small lagunes at the border of the lake Wstensjo, near Christiania, and
in widenings of the river Glommen, at Nipen. In both localities it only occurred
quite occasionally.

Distribution.—Sweden (Lilljeborg).

43. Leptocyelops Lilljeborgi, G. O. Sars, new name.
(Pl. XLV).

Cyclops serrulatus, Lilljeborg, Synopsis, p. 81, Pl. V, figs. 1—6 (not Fischer).

Specific Characters.— Female. Body somewhat less slender than in the
last-described species, and more resembling in shape that of L. agilis. Caudal
rami, however, more produced, nearly attaining the length of the last 3 segments
combined, and slightly flexuous, with the distal part somewhat divergent; outer
edge distinctly denticulated throughout, the denticles being especially conspicuous
in the distal part; middle apical sete of the usual structure; seta of inner corner
unusually prolonged, attaining almost the length of the corresponding ramus;
spine of outer corner likewise somewhat longer than usual, though much shorter
than the said seta. Anterior antenne long and slender, reaching, when reflexed,
to the end of the 2nd segment, lateral rib of the outer joints well marked and
on the proximal part of last joint divided into a number of well-marked denticles,

otherwise only very faintly striated. Posterior antenne and oral parts of normal

10 — Crustacea.

74

structure. Natatory legs likewise much as in the preceding species, though having
the apical spines of the rami more coarsely denticulate; those of inner ramus in
4th pair very unequal, the inner one being nearly twice as long as the outer.
Last pair of legs with the spine of the inner edge much feebler than in the 2
preceding species, and only minutely denticulated. Ovisacs of moderate size and
somewhat divergent. Seminal receptacle with the anterior part very broad,
occupying almost the whole width of the genital segment, and having the front
edge nearly straight.

Colour olivaceous, with a more or less brownish. tinge.

Length of adult female only slightly exceeding 1 mm.

Remarks.—This form was identified by Lilljeborg with Cyclops serru-
latus of Fischer, chiefly on account of a short note given by that author, according
to which, on a strong amplification, irregular rows of very small spinules were
traced on the outer joints of the anterior antennze. As however similar spinules
are also stated to occur on the tail and on the trunk segments, it seems to me
very questionable whether this structure in reality refers to the dentate portion of
the lateral rib, as opined by Lilljeborg. In any case the figures given by Fischer
are evidently not referable to the present species but to C. agilis Koch. Through
the kindness of Prof. Wirén of the Upsala University, I have had the opportunity
of examining the type specimens from which Lilljeborg’s description was made.

Occurrence.—I have found this form occasionally in several places near
Christiania, sometimes in small tarns, sometimes in ponds and ditches. In a sample
taken in France by Dr. Sig. Thor, and kindly sent to me for examination, this
form occurred not unfrequently together with Z. agilis, and could at once be
distinguished from the latter by the rather different shape of the caudal rami.

Distribution.—Sweden (Lilljeborg), France (G. O. Sars); very probably
also distributed in other parts of Europe.

44. Leptocyclops maecruroides, (Lilljeborg).
(Pl. XLVI.

Cyclops macruroides, Lilljeborg, Syuopsis, p. 85, Pl. V, figs. 7—11.

Specific Characters.—Female. Body somewhat more slender than in the
last described species, with the tail comparatively longer in proportion to the
anterior division. Caudal rami very narrow and prolonged, exceeding somewhat
in length the last 3 segments combined, and diverging very little, though some-
what remote at the base; outer edge distinctly denticulate throughout, seta of
that edge somewhat remote from the end; middle apical sete of the usual

75

appearance; seta of inner corner scarcely more than half as long as the corre-
sponding ramus, though longer than the spine of the outer corner; the latter
comparatively short and thick. Anterior antenne less elongated than in the
preceding species, scarcely reaching, when reflexed, beyond the middle of the
2nd segment, lateral rib of the outer joints very finely denticulated in the proximal
part of last joint, otherwise quite smooth. Posterior antenne and oral parts
scarcely different in structure from these parts in the preceding species. Nata-
tory legs rather strongly built, but likewise of the usual structure. Last pair of
legs with the spine of the inner edge comparatively shorter than in L. Lilljeborgi,
but much thicker and coarsely denticulated. Ovisacs rather large and somewhat
divergent. Seminal receptacle with the anterior part less broad than in the last
described species.

Colour light yellowish grey.

Length of adult female amounting to 1.30 mm.

Remarks.—Vhis species is nearly allied to L. Lalljeborgi, but may be
easily distinguished by the very narrow and prolonged caudal rami and by the
somewhat shorter anterior antenne. It also grows to a considerably larger size
than that species. The North American form, Cyclops elegans Herrich, of which
I have had specimens for examination, is not, as opined by Lilljeborg, identical
with the present species, as it has the anterior antennz much more elongated
and also exhibits some differences in the structure of the caudal rami and of
the last pair of legs.

Occurrence.—I have only met with this species in large lakes, for instance,
iu the Maridal Lake near Christiania, and in the great lakes Mjosen and Tyrifjord.
It is generally found at a depth of a few fathoms, near the margin, but in some
cases it descends to much greater depths. In Lake Mjosen I have for instance
taken it occasionally down to 50 fathoms.

Distvibution.—Sweden (Lilljeborg), peninsula of Kola and northern part

of Siberia (same author).

45. Leptocyclops macrurus, G. O. Sars.
(Pl. XLVII).
Cyclops macrurus, G. O. Sars, 1. c. p. 45.

Syn: Cyclops maarensis, Vosseler.

Specific Characters.—Female. Body rather slender, with the tail much
produced and only slightly shorter than the anterior division. Caudal rami ex-

ceedingly long and narrow, almost attaining the length of the whole remaining

part of the tail, linear in shape and scarcely at all divergent; outer edge for the
greater part of its extent quite smooth, with only a short, somewhat oblique row
of 4 or 5 small denticles just in front of the seta of this edge; the latter rather
remote from the end, and attached somewhat dorsally; middle apical sete of the
usual structure; seta of inner corner fully twice as long as the spine of the outer.
Anterior antenne much shorter than in any of the preceding species, scarcely
reaching, when reflexed, to the end of the cephalic segment, outer joints less
narrow and without any distinct lateral rib. Posterior antenne and oral parts
of the usual structure. Natatory legs likewise built in the usual manner; apical
spines of inner ramus in 4th pair rather strong and coarsely denticulate, the
inner one only slightly longer than the outer. Last pair of legs with the spine
of the inner edge very small. Ovisacs of smaller size than in the other species
and closely appressed to the tail. Seminal receptacle with the anterior part
narrowly exserted on each side.

Colour light yellowish grey, with a faint olivaceous tinge.

Length of adult female amounting to 1.10 mm.

Remarks.— This species was established by the present author as early
as the year 1863, and has been admitted by all subsequent authors. It is indeed
easily distinguishable by its extremely long and narrow caudal rami, which give to
the tail a more slender appearance than in most other Cyclopide, a character which
has given rise to the specific name proposed. According to Dr. Schmeil, the
Cyclops maarensis of Vosseler is identical with the present species.

Oceurrence.—Like the last described species, this form chiefly belongs to
the fauna of large lakes, occurring there in shallow water among aquatic plants.
It is also occasionally found in small lagunes and ponds formed by the reflux
of the water in these lakes.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil),
Poland (Lande), France (Richard).

Gen. 16. Platyeyclops, G. O. Sars, n.

Generic Characters.—Body comparatively robust, with the anterior part
conspicuously applanated and the epimeral parts expanded laterally. Last trunk-
segment short and broad, with the lateral parts more or less densely hairy.
Tail robust, sub-cylindric in shape, and having the genital segment comparatively

short and stout. Caudal rami of different shape in the different species, and

as

generally clothed on the dorsal face with oblique rows of fine spikes; middle
apical sete comparatively strong and rather unequal in length, being minutely
denticulated for a good part of their length. Anterior antenne short, with the
number of joints more or less reduced. Posterior antenne likewise less slender
than in the preceding genera. Both pairs of maxillipeds comparatively short
and stout; the posterior ones with the outer 2 joints confluent. Natatory
legs with the basal part broad and flattened, the rami 3-articulate and nearly
equal in length; middle joint of inner ramus in Ist pair with only a single seta
inside; terminal joint of same ramus in all the pairs comparatively small. Last
pair of legs in some cases well defined, each forming a small lamella carrying 2
thin sete and inside them a denticulated spine, in other cases replaced on each
side by 3 spines only. Seminal receptacle short and broad, not produced behind.

Remarks.—The present genus answers to the last of the groups of
Cyclopses distinguished by Dr. Schmeil, viz., his “phaleratus—affinis—-fimbriatus
group’. The species belonging to this genus are especially distinguished by the
pronouncedly applanated form of the anterior division of the body, which gives
them a rather characteristic appearance, and also exerts a certain influence on
the movements of the animal. It is indeed from this character that the generic
name here proposed has been derived. In some particulars a certain agreement
with the preceding genus Leptocyclops may be found to exist; but in other points
the species here under consideration differ so much, that they cannot properly
be brought together in the same genus. In addition to the 3 Norwegian species
described below, the Cyclops Popper Rehberg is unquestionably referable to the
present genus. This form, it is true, has been considered by Dr. Schmeil as
merely a variety of C. fimbriatus Fischer; but in, my opinion it ought to be
kept apart as a distinct, though nearly allied species, Further, among the
several species of Cyclops recorded by the present author from Lake Tanganyika,
the 2 forms, C. oligarthrus and C. compactus are undoubtedly members of the
same genus. We know accordingly as yet of 6 different species belonging to
the present genus.

78

46. Platyeyelops phaleratus, (Koch).
(Pl. XLVITI)
Cyclops phaleratus, Koch, |. ¢., Heft 21, Tab. 9.
Syn: Cyclops canthocarpoides, Fischer.
5s ‘ lascivus, Poggenpol.

Specific Characters.— Female. Body rather short and stout, with the
anterior division pronouncedly applanated and broadly oval in outline, greatest
width about equalling */; of the length and occurring in the middle. Cephalic
segment of moderate size, about the length of the 4 succeeding segments com-
bined, and evenly rounded in front. Last trunk-segment comparatively broad,
with the lateral parts shghtly produced and minutely hairy. Tail unusually
robust, somewhat exceeding half the length of the anterior division, and having
the posterior edge of all the segments coarsely denticulated ventrally and later-
ally; genital segment scarcely as long as the 2 succeeding segments combined,
and of nearly equal width throughout; Jast segment very short. Caudal rami short
and thick, about equalling in length the penultimate segment, and scarcely diver-
gent, distal part a little contracted and obliquely truncated at the end, upper
face crossed by 3 obliquely curved rows of very delicate spikes, outer edge
clothed in the middle with a few small spinules, seta of this edge very small
and not far from the end, issuing somewhat dorsally; middle apical sete very
strong and clothed for the greater part of their extent with small appressed
spinules, the inner one more than twice as long as the outer; seta of inner
corner small, scarcely longer than the spine of the outer. Anterior antenne
much shorter than the cephalic segment and only slightly dilated in their proximal
part, being composed of 16 joints clothed with comparatively short simple sete ;
Ist and 6th joints the largest. Posterior antenne very strongly built, with the
first 2 joints imperfectly defined, 3rd joint densely hairy in front and on the
upper face, its seta very short, spiniform; terminal joint much shorter than the
penultimate one, apical sete of both joints very coarse and curved. Mandibles
and maxille of usual structure. Anterior maxillipeds very short and stout, with
the basal part much dilated. Posterior maxillipeds likewise unusually stout,
with the first 2 joints imperfectly defined, the 2nd exhibiting outside a ledge
densely clothed with spinules, last joint very small and conically produced inside,
carrying 2 short, thick, hairy sets and outside them 2 thin bristles. Nata-
tory legs distinguished by their exceedingly broad basal part and the coarsely
spinulose rami; 2nd basal joint in Ist pair only slightly produced at the inner
corner, but having the deflexed spine of quite an unusual size; terminal joint of

9

outer ramus in lst—3rd pairs with 3 coarse spines outside, in 4th pair with

{hes)

only 2 such spines; apical spine of inner ramus in Ist pair not particularly
strong; those in 4th pair very unequal, the inner one more than twice as long
as the outer and equalling in length the 2 outer joints of the ramus combined.
Last pair of legs imperfectly developed, and replaced on each side by 3 strong
ciliated spines attached to the lateral corners of the corresponding segment, the
outermost spine being somewhat thinner and less densely cihated than the other 2.
Ovisacs of moderate size, oblong oval in form and generally closely appressed
to the sides of the tail. Ovarial tubes extending backwards more or less far within
the tail, generally to the penultimate segment. Seminal receptacle short and
broad, occupying almost the whole width of the genital segment.

Colour generally dark reddish brown, with the Ist free trunk-segment
somewhat lighter.

Length of adult female about 1.10 mm.

Remarks.—This very characteristic form was first recorded by Koch,
who has given a very recognisable figure of an adult female specimen. It was
subsequently redescribed by Fischer as a new species under the name C. can-
thocarpoides, a name that was also adopted by some of the subsequent authors.
According to Dr. Schmeil, the Cyclops lascivus of Poggenpol is also identical
with the present species.

Occurrence.—I have found this form occasionally in stagnant pools near
Christiania, especially in such as have their surface more or less densely
covered with Lemma. Like the other species of the present genus, it is a true
bottom form, keeping constantly close to the ground, along which it moves with
great rapidity. Even when out of the water, it has the power for some time
of creeping along a plane surface. The manner in which the male gets
hold of the female during copulation, is rather different from that observed in
most other Cyclopide, and more resembles that generally found in the Harpac-
ticoida. As in the latter, the male grasps the female with his prehensile anterior
antenne dorsally across the tail, and the hold is so firm that it not infrequently
happen that the two sexes remain tied together in this manner after being killed
in alcohol.

Distribution.—Throughout Europe, Turkestan (H. Ganin), North America
(Herrich), Australia (G. O. Sars).

80

47. Platyeyclops affinis, G. O. Sars.
(Pl. XLEX).
Cyclops affinis, G. O. Sars, lL. ¢., p. 47.

Syn: Cyclops pygmeus, Rehbere.

Specific Characters.—Female. Body somewhat less robust than in the
preceding species, with the anterior division comparatively narrower. Cephalic
segment considerably exceeding in length the 4 succeeding segments combined,
and narrowly rounded in front. Last trank-segment with the lateral parts
slightly produced and clothed at the edge with slender recurved spinules. ‘Tail
about equalling in length */; of the anterior division, and slightly tapered distally;
genital segment about as long as the 2 succeeding segments combined, and some-
what dilated at the base, last segment more fully developed than in P. phaleratus,
though smaller than the penultimate segment. Caudal rami resembling in shape
those in that species, but a little more produced; seta of outer edge very small,
and attached near the end somewhat dorsally; upper face crossed by a row of
small spikes extending from the said seta obliquely anteriorly; middle apical
sete strong and minutely denticulated for some part of their length, the inner
one about twice as long as the outer, and equalling about half the length of the
body; seta of inner corner very small, shorter than the spine of the outer.
Anterior antennsz shorter than the cephalic segment, and, as in the preceding
species, not much dilated in their proximal part, being composed of 11 joints
clothed with short, simple sete. Posterior antenne far less robust than in.
P. phaleratus, with all the joints well defined. Maxillipeds resembling in struc-
ture those in that species; the posterior ones, however, wanting the spinulose
ledge of the middle joint. Natatory legs with the basal part less broad and the
rami less coarsely spinulose outside; 2nd basal joint in Ist pair obtusely produced
at the inner corner, with the deflexed spine rather slender, terminal joint of
outer ramus in Ist and 2nd pairs with 3 spines outside, in 3rd and 4th pairs
with only 2 such spines; apical spine of inner ramus in Ist pair rather coarse;
those in 4th pairs, as in the preceding species very unequal, the inner one
being more than twice as long as the outer and conspicuously bent inwards;
middle joint of same ramus with only a single seta inside. Last pair of legs
well defined, each forming a small sub-quadrangular lamella carrying inside a
very slender denticulated spine, outside a seta of about same length, and in the
middle another much smaller seta. Ovisacs comparatively smaller than in the
preceding species and containing only a limited number of ova. Seminal recep-

tacle less broad.

Copepoda

Cyclopoida. PLO,

Cyclopide.

G. O. Sars, del.

Cyclops varicans, G. O. Sars.

Copepoda

Cyclopidz. Cyclopoida. Pl. XXXIV.

GaO: Sars, del.

Cyclops bicolor, G. O. Sars.

Copepoda

Cyclopoida. Pl. XXXV.

Cyclopide.

G. O. Sars, del.

Mesocyclops obsoletus (Koch).

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~

Pi)

.
ry
ry
rot!

4nd

w a

al
i
vv
7 oe)

=
3

: <>
ig,
|
cell

a r
ae > . :
= kaa - 5 nye i oe ~
7 Oo oy “ a
fai Wn) aa va a
te - as
y oa
7 wa oo) 7
pa AR 7 : . , 7 .
Dy ris - s.: ¥- > 7
} _ Min J < ‘
< i
a a wid -_ _ 1
> i
ah @
‘ ©

Copepoda

Pl eeey i

Cyclopoida.

Ga Omsarse del:

Cyclopide.

Mesocyclops oithonoides, G. O. Sars.

se

i
oe
eae
®
ry >
a
_ 1
Fo ar
— :
Low’ _
om, =
faba.
4
w
1
’ [ w
a
pA *>
° :
1 7 i ; =§ 1 =
_ : : a 7 7 - ; _ de
é : ; e Z 2 . ;
fei : : : oe 7 - 7 ~ ys
i A = bi ’ , pe. a P ; - i 7 vs 7
= ‘ ee) 7 oem a : - 7 : a
as : ea ra» ® « a 7 7 a :
; he : sd ; ee : - °
_ ty 7 7 7 is nae < 7 = ave ¢ _-. _ a * a - = i = -

Copepoda

Cyclopoida. Pl; XXXVI

Cyclopide.

GaOmsarsiedel:

Mesocyclops crassus, (Fischer).

pps NS

eh

i
ion
7 naa
>
*
, 4
'
“
!
7 ¢ :
a ry ak ee
< . : : uate a ae Ms
a) 7 : =. a ae ¥
7 a: - ——S so =
Oe Ae me = Pay 4 oe. _
2 : 7 : ~ - i
if * a ;
a ; -— 7 het
ad A=? an} : a i
a bal
%, : s = a . q 5 ¥
i ie aire, ’
=a a y ‘ ane a a ‘
1 -
7 af . | = ge : a
: Fs
int ae, es Lae thao Rea
oa / a 4 oe y nid

Copepoda

XXXVIII.

Pl

Cyclopoida.

Cyclopide.

GeOh Sars del:

Mesocyclops Dybowskyi, (Lande).

Copepoda

Cyclopoida. Pl. XXXIX.

Cyclopidz.

OsyeSars) del:

G.

Mesocyclops gracilis, (Liiljeb).

ie eae ee i TN, 9 eo a Se ne

7 a cay SN OS Ee ede fears
te Tan a ng

Sieve at 7 7 a are eat oo

1 7 3
' |
: 7 oy al 7 er 7 Mare Ye see mie te rose
) &. * ~ | ad i: =
fe ae
7 — oe o
‘ * a - _ . = - ~ ° -
f a i : a : a eo Ne
- > a - _ oa ti aA =
a nee aoa
= ’ ~ _

7 =
. =
( Pre aa.
Sar 7
, ray i
aif
(i Ge: =
7 7 i ten ;
a be
") * a a
a = ;
it as 7 iw oa :

— a =
! ; ti ; 7 a :
2
=)
= : : 4
i ‘ he
. is
= > 7
7 1S ¢
: _
a i i ;
: : it 7 ae
fp
Ls : é Bs
1 , _ -
; — : ;
so
os 4.
, we, J
en 7 %:
-_ = ;
esi ,
» 7 2
>.
7 eo ... : -
: : ° x $ 7
= - _ =
- : 7
7r- -—
4 J : iS | - 7 é it
- ; : =
= e
if FS
; b -_ a ti
a A A
we : — . . - 7 - a
aa = _ = a = s -
a - ° ; a)
a
aX “ : ~N

Copepoda

Cyclopide. Cyclopoida. Ply lee

G. O. Sars, del.
Pachycyclops signatus, (Koch).

7 3 P
Se eke

oe,

oa Bde YF fs

Pig — on
tas co vei
ns aa

bleh ~ ae _—
, - vied -
i: ; A ; ' ; =
7 9 Pa
‘ . = : | ; |
= 7 in
; : a4
:
te ' 7 Fe ; . "
I mee ; :
—.- a f rr
r © ' ~ , i
7 hy v . - - = | =
= - ‘i . a oy Bi, ss
: i? ; an | ; |
a Com ro = : © ent a
po pf P a
oa i

Pate
7
-

z ia z es hi
: Pos ? i in » —_
| v1 fi et ae a le
ie o oa - 7 : : : r.
. a= Je > oP | ns - 7 :
a ; a 9 i‘ - i = as : bf =s : ; E ’
ir Pon yar 7 ; ys Sen | Th gam 7 oe
Oy La » ¢ ¥ a _ a ‘ Bs
‘ Le a) ; J ‘ bed “
4 ; : 7 ; ; .
: , ma ve a
a fl -— :
r) ey i
wy 7 : .
i a. - ™ 7 . }
io ® ao 7 :
- “ Uy 7 | |
? 7 a 7 |

Copepoda

Cyclopide. Cyclopoida. Phe xr

G, ©. Sars, del.

Pachycyclops bistriatus, (Koch).

: : : ~ ’ a
7 y
7 — 7 .
~ ae 7 =~. - 5 Li a
a ; ae _ <7

‘
a
7
oa

j - E ;
- j -
7 a be oe a ~ ton » te ~ =
a E x P
- a ~ way = Tg - y ;
= ‘

- uF
= y q ; -
- - , , “
. i : - * =
— : » a ee nee
, : -
7 ap ol
io : - © — an
-

=a + — ee 7 @
ie 7Y fp
_ : . ae i a a : -
; a ee an
- 2
4 : Ms » a S =
be 7 ‘ = ;
¥ ~ -
v fie
ft 7 :
is bal _ ;
2 it wo ee
othe ; > ae
= eepree
° =
< a ne
A 7 > a =
2 4 _——
a Ad 7
i “
» :
= :
i, a i
> 7 - :

_ ae
ee
~e \ P, pe
7 . oe = 7
7 aad 7
{ ed ( (
R=
- -
is = re oh
iv a 7 =
7 f 7 a
= _ =
<= <3 O52 eee _
i

©

Copepoda

Cyclopoida. Pl. oxi

Cyclopide.

Ga O} Sars; del:

Pachycyclops annulicornis, (Koch).

Copepoda

Pl; XE.

Cyclopoida.

Cyclopide.

GaOmsatsiacel:

Leptocyclops agilis, (Koch),

Copepoda

Cyclopide. Cyclopoida. Pl. XLIV.

GalO> Sars; del:

Leptocyclops speratus, (Lilljeb).

+ ee et

sa

- : a
2 ! ¢ :
a a wv ee Bic?
» > =at re
’ a ¥ i 2 ro
pla el
, by —
je yf ify, e a”

¢ 7
ee.
? i, U
i] A :
1 7 wg 6's oa
} i If
A ; _
a ae
’ See A.
tT i
4 7 ae a at
°
- =
= ~ bi os
= ¥ -
; . -
7 ¥ ad ve
a - bad = “A uy _
a . a —
oy - . _ os
ia ne 2 ¢ +7 :
= rm
i
i fi
4
t a
—
J aa 7
-—— = 5
f
’
be _ ¥

emt. See a ert

’

Copepoda

Cyclopoida. Pl XLVe

Cyclopide.

GOs Sats, del:

Leptocyclops Lilljeborgi, G. O. Sars.

4m

iE

1%

7

Copepoda

Pl. ews

Cyclopoida.

Cyclopide.

oe
ren eins

enmeanan et

Se ee

G. ©. Sars, del.

Leptocyclops macruroides, (Lilljeb).

Copepoda

Cyclopidz. Cyclopoida. Pl XLV iM.

GaOe Sars del:

Leptocyclops macrurus, G. O. Sars.

7 7 = ’ To _
4 shy
: ¥ 7
: Fes :
ah ~ Dl 3 ’ ' .
: ras rs coe Ve we = <¢ —
= - i (@:
iv ce 7 Wi 7 ley Lao ne
Ca = ) J
aka on* , 1 , 7 Pa _ i Ce gy! Cote
oa . . ee oe
7 : ; 7 ‘a r as 7
- > - as :
: Sa *
: 2
# , ‘ ; -
of 5 = :
pane 7 ; i
» ’ 7 7
@ 7 ran ;

>
‘
ee j
wn is
a r
'
i
‘
i? =
. =~ 4
' To 6
4 ri
eo.
—— a2 a)
ie eae fe
: ate
. i ae
© i me
’ athe :
- — s
' =
“a “A
- =
7
-
4
? =
—* _ = © #
pad
-
‘ce
~ iJ ,
4
od ®.
=. =
- =
rs c
i 2.
7 5 i
7

a
> .%

a ah
; a a ae iz a ; =
- , Ve ad © ‘ - = j
' } 4 ot : - aoe
’ wit a) Ny 7 ba
t : - oy . a os : oo oo : -
o P 7 7 ; es f 7 ve :
Fe | - 4 oa ae ns a
~ = 7 ”
See { ee oa a An,
- = eo = Ft rg =

Copepoda

Cyclopoida. Pie XE Vie

Cyclopide.

= oe

ao

Wat
SSR

GAO} Sars) del.

Platycyclops phaleratus, (Koch).

=
® ri

cas be

°

ar
a
ie)

o

“4 ®

7 eet a}

s) >

Pa 4 n°
ty cs re rhe)

rn fa av

AN ACCOU NT

“OF THE

NORWAY

WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

° BY

G. 0. SARS

-NOLEVI

‘COPEPODA
CYCLOPOIDA

PARTS VII & VMI
CYCLOPID (concluded), ASCOMYZONTIDA:

WITH 16 AUTOTYPIC PLATES

BERGEN
PUBLISHED BY AE BERGEN MUSEUM
2 i SOLD. BY
ALB. CAMMERMEYER’S FORLA G, CHRISTIANIA

~

1915

ees

(

81

Colour generally dark bluish grey.

Length of adult female about 0.75 mm.

Remarks.—In its general appearance this form somewhat resembles the
preceding species, but is of much smaller size and has the body less robust.
It moreover exhibits several well-marked differences in the structure of the
antennze and legs, as indicated in the above diagnosis. The Cyclops pygmeus
of Rehberg is unquestionably identical with the present species.

Occurrence.—I have taken this form in similar localities to those in
which the preceding species has been found. It also occurs occasionally at the
borders of large lakes or in closed lagoons formed by the reflux of the water
in these lakes during the dry season.

Distribution.—-Throughout Europe, Turkestan (Uljanin), Australia(G,.O.Sars).

48. Platycyelops fimbriatus (Fischer).
(Pl. L).

Cyclops fimbriatus, Fischer, Beitriige zur Kenntniss der Cyclopiden (Fortsetzung). Bull. Soe. Imp.
Moscou 1853, p. 94, Pl. IIT, figs. 19—28, 30. :

Syn: Cyclops crassicornis, G. O. Sars (vix Miiller).

Specific Characters.—Female. Body comparatively robust, with the an-
terior division, as in the 2 preceding species, pronouncedly depressed and oval
in outline. Cephalic segment large, considerably exceeding in length the 4 suc-
ceeding ones combined, and narrowly rounded in front. Last trunk-segment with
the lateral parts slightly produced and clothed with stiff, posteriorly-curving hairs.
Tail about equalling in length ?/; of the anterior division, and slightly tapered
distally; genital segment longer than the 2 succeeding ones combined, and some-
what dilated in front; anal segment shorter than the preceding one, and nearly
transversely truncated at the end. Caudal rami much more prolonged than in
the 2 preceding species, almost attaining the length of the last 3 segments
combined, and rather remote at the base, being narrowly linear in form and only
slightly divergent; seta of outer edge attached at some distance from the end, and
somewhat dorsally; upper face of each ramus exhibiting, just in front of this
seta, a short transverse row of small denticles; middle apical sete rather strong,
and clothed in their median part with scattered, stiff hairs, the inner one being
nearly twice as long as the outer and about the length of the tail; seta of inner
corner a little longer than the spine of the outer. Eye large and conspicuous.
Anterior antenne scarcely more than half as long as the cephalic segment, and

rather dilated at the base, being composed of only 8 joints, densely clothed with

11 — Crustacea.

89

strong, partly ciliated setw. Posterior antenne with all the joints well defined,
the terminal one very short, scarcely more than half the length of the penulti-
mate one. Maxillipeds short and stout, the posterior ones, however, somewhat
more fully developed than in the 2 preceding species. Natatory legs resembling
in structure those in P. phaleratus; apical spine of inner ramus in Ist pair,
however, comparatively larger; those in 4th pair rather unequal, the inner one
being about twice as long as the outer. Last pair of legs well defined, resembling
in structure those in P. affinis; spine of inner edge, however, considerably shorter.
Ovisacs in some cases rather large, oblong oval in form, and closely appressed
to the tail. Seminal receptacle rather broad, transversely elliptical in form.

Colour whitish, with the ovarial tubes dark bluish; eggs in the ovisacs
generally of a similar dark hue; eye bright red.

Length of adult female about 0.90 mm.

Remarks.—This form was at first identified by me with Cyclops crassi-
cornis of O. Fr. Miiller; but it is very questionable if the form so named can
be assigned to the present species, or even to the genus Cyclops. Fischer’s
description, on the other hand, does not leave any doubt about the identity of
his species with that here in question. It may be easily recognised from either
of the 2 preceding species by the short and thick anterior antenne, and the
rather different shape of the caudal rami.

Occurvence.—1 have met with this form only occasionally in small ponds
and ditches, more frequently in larger lakes, where in some cases it descends to
rather considerable depths. Thus in Lake Mjosen I have taken it in depths
down to 50 fathoms. Like the other species of this genus, it is a true bottom-
form, always keeping close to the ground.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil),
Poland (Lande), Russia (Fischer).

Section 2. Siphonostoma.

General Characters.—Anterior antenne in male generally (but not always)
geniculated. Posterior antenne, as a rule, provided with a very small uniarticulate
appendage as the rudiment of an outer ramus. Oral parts not adapted for
mastication, the anterior and posterior lips being generally produced to form a

prominent cone, terminating in some cases in a long siphon. Mandibles with

the masticatory part styliform. Mavxille feeble, and generally divided into 2 seti-
ferous lobes. Both pairs of maxillipeds subcheliform, adapted for prehension.
Natatory legs, as a rule, well developed, with triarticulate rami.

Remarks.—The name “Siphonostoma” is here taken in a much more
restricted sense than is done by its proposer, Thorell, viz., to designate only a
section of semiparasitic Cyclopoida, in which the mouth, by the prolongation of
the anterior and posterior lips, has assumed a more or less suctorial character,
recalling that found in some of the true parasites, for instance in the Caligoida.
Yet the characteristic Cyclopoid appearance in all of them has been preserved,
and none of them are to be regarded as permanent parasites, as they have the
power to leave their hosts at will, and to move freely through the water by the
aid of their generally well developed natatory legs. Indeed, many of the forms
have hitherto only been found in such a free condition, though the structure of
the mouth organs evidently show them to be adapted for temporary parasitic habits.

In the restriction here adopted, the present section answers fairly well
to the family Asterocheride of Giesbrecht. This family, which is included in his
great division Ampharthrandria, comprises several types, which are so widely
different, that in my opinion they cannot properly be combined within one and
the same family. (nesbrecht himself has also been aware of this difference, and
for this reason has established within the family Asterocheride a number of so-
called sub-families. These I regard as true families, and their number will be

still somewhat increased.

Fam. 4. Ascomyzontide.

Characters.— Body Cyclops-like, with the anterior division more or less
dilated, the posterior narrow and attenuated, Anterior antennz generally slender
and composed of a great number of articulations, the outermost of which form
a distinctly-defined terminal part, the joint preceding this part being constantly
provided with a very fully developed sensory filament; same antennz in male
more or less distinctly hinged, with the number of joints somewhat reduced.
Posterior antenne moderately strong, 4-articulate, 1st, or coxal, joint short, the
2 succeeding ones more or less prolonged, and forming together a geniculate bend,
last joint small, carrying on the tip a slender spine accompanied by 2 or 3 short

bristles, one of which issues from a knob-like prominence of the anterior edge.

84

Oral cone more or less produced. Mandibles penetrating the cone up to its apex,
and having outside at the base a slender, generally bisetose palp. Maxille with
the inner lobe the larger. Anterior maxillipeds, as a rule, shorter and stouter
than the posterior, and having the basal joint imperfectly defined, terminal claw
uniarticulate or im some cases biarticulate; that of the posterior ones always
3-articulate. Natatory legs on the whole of normal structure. Last pair of legs
biarticulate, with the proximal jojnt laminar and in most cases imperfectly defined
from the segment, distal joint lamelliform, and extended laterally.
Remarks.—This family, established by Thorell, is here taken in a more
restricted sense than is done by that author, who comprised within it also the genus
Dyspontius, which ought to be referred to quite a distinct family. Nor does it
fully answer to the sub-family Asterocherine of Giesbrecht, as I have found it

necessary to remove the genus Acontiophorus in to a separate family.

Gen. 17. ASCOMYZON, Thorell, 1859.
Syn: Asterocheres, Boeck.
Cyclopicera, Brady (part).
» Artotrogus, Brady (part).

Generic Characters—Body pronouncedly depressed, with the anterior
division broad and expanded. Cephalic segment very large and having the
rostral prominence more or less distinctly defined and incurved. Penultimate
trunk-segment much smaller than the preceding one, and partly covered by it; last
segment still smaller, and firmly connected with the genital segment. ‘Tail not
much prolonged, and composed in female of 3, in male of 4 segments; genital
segment in female considerably dilated, and having the lateral edges clothed with
stiff hairs; that of male still more tumefied, and provided at the end, on each
side, with a prominent triangular lobe carrying a spiniform seta. Caudal rami
comparatively short and without any seta on the outer edge; apical setz of mode-
rate length, the 2 mediate ones being, as usual, the largest, and distinctly jointed
at the base. Anterior antenne slender and elongated, exhibiting a proximal,
somewhat thicker portion composed of 9 short articulations, and a much narrower,
linear distal portion; terminal part, as a rule, composed of 3 articulations, which
however in some cases may be more or less completely coalesced; same antenne
in male distinctly hinged. Posterior antenne with the penultimate joint almost as
long as the preceding one. Oral cone, as a rule, pyriform in shape, though in

some cases abruptly narrowed to form a slender straight siphonal tube. Man-

85

dibles with the masticatory part very narrow and lancet-shaped at the end; palp
biarticulate. Maxille with the lobes rather unequal, both carrying on the tip 4
sete. Maxillipeds more or less powerfully developed, the posterior ones having
in male a slight palmar projection near the base of the hand. Natatory legs of
moderate size, terminal joint of outer ramus in Ist pair with only 2 seta inside,
in the other pairs with 4 such sete. Last pair of legs with the proximal joint
imperfectly defined from the segment, but carrying outside the usual seta; distal
joint somewhat tapered distally and ciliated on both edges, apex provided with 2
curved sets, generally accompanied inside by a smail bristle.

Remarks.—This genus, which is the type of the family Ascomyzontide,
was established in the year 1859 by Thorell, to comprise a form found by him
parasitic in the branchiai cavity of Ascidians. In the very same year Boeck
established his genus Astevocheres, which has turned ovt to be identical with
Thorell’s genus. Although Boeck’s paper seems to have been published a
little prior to Thorell’s Monograph, it appears to me that the generic name
proposed by Boeck can scarcely be admitted, because the species of this genus are
by no means exclusively parasites of Asterids, but are found to infest many other
invertebrate animals. For the same reason, of course, the family-name Asterocheride,
proposed by Giesbrecht, ought to be rejected. Brady has confounded this genus
with the genus Artotrogus of Boeck, which in reality belongs to quite a different
family, and one of the species (A. latwm) has moreover been referred by that
author to his genus Cyclopicera. The present genus seems to be very rich
in species. In the following pages will be described 6 different species belonging

to the Fauna of Norway.

49. Ascomyzon asterocheres, Boeck.
(Pl. LI & Lil).

Asterocheres Lilljeborgi, Boeck, Tvende nye parasitiske Krebsdyr. Chr. Vid. Selsk. Forh. f. 1859,
p. 6, Pl. IL

Specific Characters—Female. Anterior division of body very broad and
flattened, its greatest width fully equalling the length. Cephalic segment exceedingly
large, being more than twice as long as the 4 succeeding segments combined, and
almost semicircular in outline; lateral edges not inflexed ; rostrum imperfectly defined,
and only represented by a slight convexity below the front. Epimeral parts of the
trunk-segments expanded laterally and acutangular behind. Penultimate segment,
as usual, much smaller than the preceding one; last segment still smaller. Tail com-

paratively short, not nearly attaining half the length of the anterior division, and

S6

gradually attenuated behind; genital segment considerably tumefied; anal segment
exceeding in length the preceding one. Caudal rami about twice as long as they are
broad, and scarcely at all divergent, tip transversely truncated, with the sete rather
unequal, the innermost but one being, as usual, the longest, and considerably
exceeding the tail in length. Anterior antenne almost equalling in length the
cephalic segment, and composed of only 18 articulations, the 3 joints of the
terminal part being fused together to form a single joint. Posterior antenne
comparatively strongly built, with the penultimate joint fully as long as the
preceding one and not much narrower; apical spine rather strong. Oral cone
pyriform in shape, and only extending to the insertions of the posterior max-
ilipeds. Mandibles with the masticatory part of the usual narrow lancet-shaped
appearance; palp rather fully developed. Maxille with the lobes less unequal
than usual, apical setze of both lobes rather strong and finely ciliated. Anterior
maxillipeds very powerfully deyeloped, with the claw exceedingly strong and
curved like a hook at the end. Posterior maxillipeds likewise rather powerful,
though somewhat less so than the anterior ones. Natatory legs less fully developed
than in most other species, and more or less incurved; their structure, however,
quite normal. Last pair of legs with the distal joint oblong in form, and _ pro-
vided, in addition to the 2 apical sete, with a small bristle at some distance from
the tip inside. Ovisacs of moderate size, oval in form, and somewhat divergent.

Male smaller than female, and having the body somewhat less broad.
Tail composed of 4 well-defined segments, the anterior of which is_ greatly
tumefied, to form the lateral hollows in which the rather large spermatophores
are received, Anterior antennz composed of 17 joints, the last 2 of which
admit of being bent upon the preceding part. Posterior maxillipeds with a
well-marked palmar prominence near the base of the hand.

Body in both sexes semipellucid, with a more or less distinct reddish tinge.

Length of adult female about 1.30 mm., of male scarcely 1 mm.

Remarks.—This form was described by Boeck in the year 1859 under
the name of Asterocheres Lilljeborgi. As, however, the term Asterocheres cannot
properly be admitted as a generic designation, I propose to use it here as a
specific one, substituting it for the original name Lilljeborgi. Hereby two advan-
tages are gained, Istly, that the name Asterocheres may be reserved for the
present species, though in a somewhat different sense, and 2ndly. that the specific
name Lilljeborgi proposed by Thorell for his species may stand unchanged.

The present form is a well-marked and easily recognisable species, being

especially distinguished by the very broad and flattened body and the unusually

87

powerful development of the maxillipeds. According to Giesbrecht, the Ascomyzon
Inlljeborgi of Canu is not this species.

Occurrence.—Boeck found this form on a specimen of Echinaster sang-
vinolentus taken at Farsund, south coast of Norway. I myself, many years ago,
collected some specimens off the west coast, and, as far as I remember, from
our common Asterias rubens.

Distribution.—British Isles (Brady, Scott).

50. Ascomyzon Lilljeborgi, Thorell.
(PRS):
Ascomyzon Lalljeborgi, Thorell, Bidrag til kinnedomen om Krustaceer, som levfa i arter af sligtet
Ascidia, p. 78, Pl. XIV, fig. 21.

Syn: Asterocheres siphonatus, Giesbr.

Specific Characters.—Female. Anterior division of body moderately ex-
panded and rounded oval in outline, the greatest width not nearly attaining the
length; epimeral parts of the segments less prominent than in the preceding
species, and rounded at the end. Cephalic segment only slightly longer than the
4 succeeding segments combined, and narrowly rounded in front; rostrum distinctly
defined, though not prominent, and blunt at the tip; lateral edges of the segment
inflexed. ‘Tail scarcely exceeding in length '/; of the anterior division; genital
segment less broad than in A. asterocheves, and exhibiting on each side, immediately
behind the genital orifice dorsally, a knoblike projection; anal segment only slightly
longer than the preceding one. Caudal rami very short, being scarcely longer than
they are broad; apical sete of moderate length. Anterior antenne long and slender,
even somewhat exceeding in length the cephalic segment, and composed of 19
joints, the outer 2 joints only of the terminal part being coalesced. Posterior
antenne less strongly built than in A. asterocheres, with the penultimate joint
rather narrow. Oral cone produced to a long and narrow siphonal tube extending
almost to the middle of the genital segment, the tube, for the greater part of
its length, being finely striated transversally; tip slightly dilated, spoon-shaped.
Mandibles with the masticatory part greatly prolonged in accordance with the
great length of the siphon; palp comparatively smaller than in A. asterocheres.
Maxille with the inner lobe moderately produced and rounded at the end, outer
lobe scarcely more than half as long and much narrower; sete of the lobes not
particularly strong and rather unequal in length. Maxillipeds less powerfully
developed than in the preceding species, the claw of the anterior ones com-
paratively short and only slightly curved at the end. Natatory legs resembling

in structure those in the said species, but of somewhat larger size. Last pair

85

of legs with the distal joint oblong oval in form, and provided with only 2 apical
sete. Ovisacs of moderate size, oblong in form, and rather divergent.

Male much smaller than female, and exhibiting the usual sexual differences.

Body in both sexes highly pellucid and nearly colourless, with only a
very faint yellowish tinge.

Length of adult female about 0.90 mm., of male 0.70 mm.

Remarks.—This form was described under the above name in the year
1859 by Thorell as the type of his genus Ascomyzon. Giesbrecht thought it
necessary to change the specific name Lilljeborgi, because this name was given
at a somewhat earlier date by Boeck to another species of this genus. If, how-
ever, my proposal to name Boeck’s species as above, be accepted, a change in
the name of Thorell’s species will be avoided.

The most prominent character distinguishing the present species is
undoubtedly the exceedingly long and slender siphon, for which reason Giesbrecht
proposed to name it A. siphonatus. The species which comes nearest to it in this
respect is the Neapolitan form A. stimulans Giesbr., in which the siphon is said
to extend almost to the insertions of the 4th pair of legs.

Occurrence.—Thorell found this form in the branchial cavity of Corella
paralellogramma, and I have myself taken it not infrequent at Risgr, south coast of
Norway, from the same Ascidian. ‘Two female specimens were also found among
dredged material procured at Grimstad, somewhat farther west.

Distribution.—Bohusliin (Thorell).

51. Ascomyzon Boecki, (Brady).
(PL ELV),
Artotrogus Boecki, Brady, Monograph of British Copepoda, Vol. III, p. 60, Pl. XCI. figs. 1—9.

Specific Characters.—Female. Anterior division of body rather broad and
expanded, with the cephalic segment very large and evenly rounded in front;
lateral parts of the succeeding segments rounded off at the end. Tail compara-
tively short, scarcely exceeding in length '/; of the anterior division; genital
segment moderately dilated and occupying more than half the length of the tail;
anal segment scarcely longer than the preceding one. Caudal rami short, about
as long as they are broad; apical sete not much elongated. Anterior antenne
nearly as long as the cephalic segment, and composed of 20 articulations, all 3
joints of the terminal part being well defined. Posterior antennze about as in
A, Lilljeborgi. Oral cone, as in that species, terminating in a narrow siphonal

tube, which however is considerably shorter, only extending a little beyond the

esse,

insertions of the Ist pair of legs, and does not exhibit any trace of a transverse
striation. Maxille with the inner lobe considerably produced and tapered distally,
the apical sete being likewise unusually slender; outer lobe very small. Max-
illipeds rather powerfully developed; claw of the anterior ones strong and much
elongated, with the end evenly curved and the concave edge finely ciliated through-
out. Natatory legs of normal structure. Last pair of legs nearly as in
A. Lalljeborqi.

Male, as usual, smaller than female, and moreover easily recognisable
by the distinctly hinged anterior antennz and by the structure of the tail.

Colour not yet ascertained.

Length of adult female about 0.90 mm., of male 0.75 mm.

Remarks.—Brady erroneously considered this form to be identical with
A. Lilljeborgi Vhorell, and the change of the specific name was merely made to
distinguish it from Asterocheres Lilljeborgi of Boeck. The species is however in
reality quite distinct from both of those forms, though nearest allied to A.
- Lilljeborgi Thorell, from which it is distinguished by the much shorter siphon.

Occurrence.—A solitary female specimen of this form was taken, many
years ago, at Bukken, SW coast of Norway, from some dredged material, and a
few additional specimens were picked up recently from the bottom-residue of a
large collecting-bottle containing a number of different invertebrate animals taken
at Rauo, west coast of Norway: I am of course unable to decide from what
hosts the specimens were derived nor is any information upon this point given
by Brady.

Distribution.—British Isles (Brady), ? Gulf of Naples (Giesbrecht).

52. Ascomyzon simulans, Scott.
(Pl. LY).

Ascomyzon simulans, Scott, Sixteenth Ann. Rep. of the Fisheries Board for Scotland, Part IU,
p. 270)- Plo x, fest 1— 9) Pl XIV. fis. 22.

Specific Characters.— Female. Anterior division of body less broad than
in the preceding species, the greatest width being much smaller than the length.
Cephalic segment of moderate size and evenly rounded in front. Lateral parts
of the 2 succeeding segments obtusely rounded, those of the last 2 segments
slightly angular. Tail very short, scarcely */; the length of the anterior division;
genital segment considerably dilated, being even somewhat broader than it is
long; anal segment about the length of the preceding one and somewhat con

tracted behind. Caudal rami exceedingly small, being broader than they are

12 — Crustacea,

9)

long; apical sete comparatively short. Anterior antenne not quite as long as
the cephalic segment, and composed of 20 articulations, all 3 joints of the ter-
minal part being well defined; proximal portion of the antenne rather thick and
very sharply marked off from the slender distal portion. Posterior antennz com-
paratively strong, with the penultimate joint somewhat shorter than the preceding
one. Oral cone not much produced, pyriform, extending scarcely beyond the
insertions of the posterior maxillipeds. Mandibles with the masticatory part
moderately prolonged and terminating in a lancet-shaped point; palp normal.
Maxille with the inner lobe of moderate size and the apical sete comparatively
short; outer lobe scarcely more than '/; the length of the inner, and much narrower.
Maxillipeds of normal structure. Natatory legs well developed, with the rami
comparatively broader than in the preceding species. Last pair of legs with the
distal joint oval in form and carrying, in addition to the 2 apical sete, a small
bristle attached inside the latter. Ovisacs of moderate size and oval in form,
being only slightly divergent.

Male differing from female in a manner similar to that in the other species.

Body in both sexes rather pellucid, with a slight rosy tinge.

Length of adult female about 1 mm, of male 0.72 mm.

Remarks.--This ferm was referred by Scott with some doubt to the genus
Ascomyzon. It is however certainly a genuine member of this genus, as defined
here, though well defined from the other species. |

Occurrence.—I have long been aware of this form, of which several speci-
mens have been collected at different times off the south coast of Norway, and
always on Sponges, for which reason I had noted it with the provisional name
A. spongiophilum. It also occurred in great numbers in the bottom-residue of
the same collecting-bottle from which A. Boecki was procured, and as this bottle
contained, besides other invertebrate animals, also a number of sponges, it is
most likely that they were in reality derived from the latter.

Distribution.— British Isles (Scott).

53. Ascomyzon latum, (Brady).
(PIM Ly):
Cyclopicera lata, Brady, Monograph of British Copepoda, Vol. III, p. 56, Pl. LAXXIX, fig. 12,
Pl. XC, figs. 11—14.

Syn: Asterocheres Boecki, Giesbrecht (part).
Specific Characters.— Female. Anterior division of body very broad and

expanded, the greatest width being almost equal to the length. Cephalic segment

large, with the frontal edge narrowly rounded. LEpimeral parts of 2nd segment

simple and not projecting at all laterally; those of 3rd (antepenultimate) segment.
on the other hand, terminating in a very conspicuous prominent corner. Penulti-
mate segment, as usual, much smaller than the preceding ones. ‘Tail considerably
exceeding in length '/, of the anterior division; genital segment rather dilated
in its anterior part and, like the other species, having the lateral edges clothed
with stiff hairs; posterior edge of this and the succeeding segment, moreover,
finely denticulate; anal segment longer than the preceding one. Caudal rami
somewhat produced, being about as long as the anal segment; apical sete rather
long and divergent. Anterior antenne very slender, equalling about in length
the cephalic segment, and composed of 20 articulations, all 3 joints of the
terminal part being well defined; proximal portion of the antennze comparatively
short and very sharply marked off from the narrow distal one. Posterior an-
tenne more slender than in A. simulans, and having the penultimate joint about
as long as the preceding one. Oral cone rather produced and gradually tapered,
extending about to the insertions of the Ist pair of legs. Mandibles with the
masticatory part long and slender; palp normal. Mavxille resembling in structure
those in A. simulans, though the sete of the inner lobe are comparatively longer.
Maxillipeds and natatory legs of normal structure. Last pair of legs with the
distal joint oval in form, and provided with only 2 apical sete.

Body pellucid, tinged in some places with light yellow.

Length of adult female 0.80 mm.

Remarks.—I cannot doubt that the above-described form is that recorded
by Brady in his Monograph as Cyclopicera lata. Brady believed this form to be
identical with Norman’s Ascomyzon echinicola; but the form so named in Giesbrecht’s
work and figured on Pl. 2, II, is certainly a different species. On the other
hand, it would seem that Giesbrecht has confounded the present species and
A. Boecki Brady. In any case the coloured figure given on Pl. 1 is unquestionably
referable to the present species and not to A. Boecki. The prominent lateral
corners of the antepenultimate trunk-segment will suffice for an immediate recog-
nition of the present species as distinct from any of the others.

Occurrence.—I have occasionally met with this form at Risgr and Grimstad,
south coast of Norway, in moderate depths among alge, and a few additional
specimens were picked up from the bottom—residue of the same collecting—
bottle in which A. Boecki and A. simulans occurred.

Distribution.—British Isles (Brady), Gulf of Naples (Giesbrecht).

92

54. Ascomyzon parvum, (Giesbrecht).
(Pl. LVID.

Asterocheres parvus, Giesbrecht. Fauna und Flora des Golfes von Neapel; 25th Monographie, Die
Asterocheriden, p. 100, Pl. 2, F.

Specific Characters.—Female. Anterior division of body less expanded
than in A. latum, the greatest width not nearly attaining the length. Cephalic
segment of moderate size and evenly rounded in front. Lateral parts of the
trunk-segments rounded off at the end, the antepenultimate segment not differing
in this respect from the others. ‘Tail almost attaining half the length of the
anterior division, and having the posterior edge of the segments perfectly smooth;
genital segment less broad at the base than in A. latwm; anal segment about
the length of the preceding one. Caudal rami resembling in structure those in
the said species. Anterior antennze not fully as long as the cephalic segment
and composed of 20 articulations. Posterior antenne moderately strong with the
penultimate joint about equal in length to the preceding joint. Oral cone shorter
than in A. latwm, only extending midway between the insertions of the posterior
maxillipeds and those of Ist pair of legs. Mandibles, maxillz, maxillipeds and
natatory legs differing very little in structure from those parts in A. latwm.
Last pair of legs likewise very similar, though having on the distal joint a small
bristle inside the 2 apical sets. Ovisacs of moderate size, oblong oval in form,
and somewhat divergent.

Colour lhght greenish.

Length of adult female scarcely attaining 0.70 mm.

Remarks. —This species is closely allied to A. latum, but is of smaller size,
and moreover easily distinguishable by the less expanded anterior division of the
body, and the evenly rounded lateral parts of the trunk-segments. Finally, the

oral cone is considerably shorter than in A. latum.,

Occurrence.—I collected this form, many years ago, in the upper
part of the Christiania Fjord, and, on account of its peculiar colour, noted
it with the provisional name A. virescens. I have also found it occasionally off
the south coast, at Grimstad and Lillesand. All the specimens were taken in
the free state among dredged material.

Distribution.—Gulf of Naples (Giesbrecht), coast of France (Canu).

oe

Gen. 18. Hehinocheres, Claus, 1889.

Generic Characters.—Body less depressed than in Ascomyzon, the dorsal
face of the anterior division being rather strongly vaulted. ‘Tail, as in that genus,
composed in female of 3, in male of 4 segments. Anterior antenne much shorter
and stouter than in Ascomyzon, though composed of a similar number of articul-
ations. Posterior antenne of comparatively feeble structure. Oral cone very short.
Mandibles with the palp uniarticulate. Maxille with one of the sete of the inner
lobe excessively developed. Maxillipeds comparatively short and stout. Natatory
legs very fully developed, with the rami unusually broad; their armature about
as in Ascomyzon. Last pair of legs with the proximal joint small and indistinctly
defined from the segment, distal joint well developed, lamelliform.

Remarks.—This genus was established in the year 1889 by Claus, to
include 2 species found by him as parasites on Echinids. Giesbrecht, however,
did not admit this genus, but referred the species to the genus Asterocheres
(= Ascomyzon), and this view was also adopted by Scott. On a closer exami-
nation of the type species, I find, however, that in some points it differs so con-
spicuously from the other species of the genus Ascomyzon, that in my opinion
the Clausian genus ought to be supported. As to the term Hchinocheres, the
same objection could perhaps be urged against it as against the term Astero-
cheres; but as in fact both species have hitherto been found exclusively on
Echinids, I do not find in the present case any imperious necessity for rejecting it.

Only the type species is represented in the Fauna of Norway.

55. Echinocheres violaceus, Claus.
(El. EVE):
Echinocheres violaceus, Claus, Halbparasitische Copepoden; Arb. Zool. Inst. Wien, Voll. III.
Syn: Asterocheres violaceus, Giesbr.
Ascomyzon Thompsoni, A. Scott.

Specific Characters.—Female. Body robust, with the anterior division
considerably tumefied and broadly oval in outline. Cephalic segment large and
evenly arched in front; rostral prominence comparatively small, though well
defined; lateral edges of the segment inflexed. Epimeral parts of the trunk-
segments rounded off at the end; penultimate segment, as usual, much smaller
than the preceding one; last segment still smaller. ‘Tail comparatively short,
with the genital segment gradually widening in front, and having the lateral edges
very finely ciliated; anal segment smaller than the preceding one. Caudal rami
about the length of the anal segment and slightly divergent; apical sete com-

paratively short, the 2 middle ones rather thicker, but not much longer than the

4

others, and densely plumose. Anterior antenne much shorter than the cephalic
segment, and composed of 20 articulations, terminal part very short, though
having all 3 joints well defined. Posterior antenne with the penultimate joint
somewhat shorter than the preceding one; terminal joint distinctly subdivided in
the middle. Oral cone scarcely extending beyond the insertions of the anterior
maxillipeds, and having the outer part abruptly narrowed. Mandibles with the
masticatory part narrow styliform. Maxille with the inner lobe short and
thick, transversely truncated at the end; principal seta very largely developed,
extending far beyond the insertions of the maxillipeds, and densely plumose;
outer lobe much smaller, and having the apical setee comparatively short. Max-
illipeds rather powerfull; claw of the anterior ones very strong and curved at
the end in a hook-like manner. Natatory legs largely developed, with the middle
joint of the inner ramus in Ist pair unusually broad and expanded. Last pair
of legs with the distal joint oval in form and rounded at the extremity, which
carries 2 sete accompanied by a small bristle. Ovisacs comparatively small,
oval in form.

Colour somewhat variable, in some cases dark violaceous, in other cases
much paler.

Length of adult female 0.90—1.10 mm.

Remarks.—This form, as above mentioned, was first described by Claus
as the type of his genus Hchinocheres. Another species of smaller size was also
recorded by the same author under the name of HKehinocheres minutus, and this
species has likewise been observed by Giesbrecht, who admits its specific difference.
The very close relationship between these 2 species, both as to structural
details and habits, would indeed seem to justify the opinion of Claus, that they
should be kept apart under a separate genus. The Ascomyzon Thompsoni of
A. Scott is unquestionably identical with the present species.

Occurrence.—I have taken this form occasionally from 3 different Kchi-
nids, viz., Strongylocentrotus drdbachiensis (small variety), EHchinus sphera and
Echinus elegans, all collected off the west coast of Norway from different depths.
The specimens found on the first-named Kchinid were all of a very dark viola-
ceous colour, like that indicated in the coloured figure given in Giesbrecht’s
work on Pl. 1; whereas those occurring on the other 2 Echinids were much
paler, of a whitish grey hue, with a very slight rosy tinge. These specimens
were also of a somewhat larger size, but otherwise fully agreeing with the dark-
coloured variety. Giesbrecht also mentiones the variability of colour in the pre-
sent species. '

Distribution.—British Isles (Scott), Triest (Claus), Gulf of Naples (Giesbrecht).

5)

Gen. 19. Dermatomyzon, Claus, 1889.

Syn: Cyclopicera, Brady (part).

Generic Characters.—General form of body resembling that in the pre-
ceding genus, the anterior division being rather tumid and evenly vaulted above.
Tail, however, composed in female of 4, in male of 5 well-defined segments.
Anterior antenne not much elongated, though composed of a considerable number
of joints; those in male imperfectly hinged and, at any rate in some cases, provided
with supplementary sensory filaments. Posterior antenne with the penultimate
joint comparatively short. Oral cone very little produced. Mandibles with the
masticatory part rather strong, knife-shaped; palp uniarticulate. Maxille with
the inner lobe normal; outer lobe narrow linear. Maxillipeds of the usual
structure; the posterior ones in male without any distinct palmar projection.
Natatory legs strongly built, though not very different in structure from those in
the preceding genera. last pair of legs with the proximal joint well detined
from the segment; distal joint lamelliform and provided with lateral spines in
addition to the apical sete.

Remarks.—This genus is also closely allied to Ascomyzon, though at once
distinguished by the tail having one segment more in both sexes. The genus
Cyclopicera of Brady, though of earher date than Dermatomyzon, cannot properly
be retained, because it was originally (in 1872) based upon a species that has
turned out to be a true Ascomyzon (A. latum). Two species of the present genus
have been described; but their specitic difference has not been admitted by

Giesbrecht.

56. Dermatomyzon nigripes (Brady).
(Pl. LIX & LX).
Cyplopicera nigripes, Brady, Monogr. of British Copepoda, Vol. IIT, p. 54, Pl. LXXXIX, figs. 1—11.
Syn: Ascomyzon Thorelli, G. O. Sars.

Specific Characters.— Female. Anterior division of body rather tumid,
broadiy oval in outline, with the cephalic segment very large and evenly arched
in front; lateral edges of this and the succeeding segment inflexed. Rostrum
triangular, but not very prominent. Lateral parts of the trunk-segments obtusely
rounded at the end. Tail nearly half the length of the anterior division and having
the segments very sharply marked off from each other, each segment being produced
at the end on each side to an acute corner; genital segment moderately broad and
imperfectly subdivided in the middle, with the lateral edges perfectly smooth;

anal segment smaller than the preceding one. Caudal rami comparatively short,

46

about the length of the anal segment, and slightly divergent, outer edge smooth,
inner finely ciliated, tip obtusely rounded; apical sets of moderate size and
somewhat spreading, the innermost but one about equalling the tail in length.
Anterior antennze much shorter than the cephalic segment, and composed of 19
joints, terminal part bi-articulate. Posterior antennz with the penultimate joint
scarcely more than half as long as the preceding one; apical spine rather strong.
Oral cone comparatively smal], extending only slightly beyond the insertions of
the anterior maxillipeds, and terminating in a sharp point apparently formed by
the extremity of the posterior lip. Masticatory part of mandibles cultriform, with
a very fine denticulation on the inner edge of the extremity. Maxille with the
inner lobe somewhat curved and tapered distally, apical sete comparatively short;
outer lobe very narrow, linear, with the apical sete longer than those on the
inner lobe. Anterior maxillipeds rather powerful, with the claw very strong and
slightly curved at the end. Posterior maxillipeds of the usual structure. Natatory
legs differing a little in their armature from those in the preceding forms, the
terminal joint of the outer ramus being provided inside in Ist pair with 3, in
2nd pair with 5 sete; same joint of inner ramus in the last 2 pairs with only
a single spine on the tip. Last pair of legs with the distal joint rounded oval
in form, and armed on the hind edge with 2 blunt spines, the extremity car-
rying 2 setz accompanied inside by a small bristle. Ovisacs comparatively small,
rounded oval in form.

Male, as usual, smaller than female, and having the anterior division
far less dilated. Tail with the segments still more sharply marked off from
each other; genital segment greatly swollen. Anterior antenne 17-articulate,

fd

and each provided with about 7 supplementary sensory filaments curving
backwards.

Body in both sexes generally of a brownish grey hue, with the anterior
antenne and natatory legs very dark-coloured, almost black; tail also partly
tinged with a dark brownish colour. |

Length of adult female amounting to 155 mm., of male to 1.20 mm.

Remarks.—This form was recorded as early as the year 1875 by Brady
& Robertson under the name of Cyclopicera nigripes, and was justly referred by
Giesbrecht to the genus Dermatomyzon, as defined by Claus. It seems however
very questionable to me, if Giesbrecht was right in identifying the form described
by Claus under the name Dermatomyzon elegans with the present species, as the
latter differs not only in its much larger size and peculiar coloration of the body,

but also in the presence on the male anterior antenne of greatly developed

97
supplementary sensory filaments. hese filaments, according to Canu, are wholly
absent in the male of D. elegans.

Oceurrence.—I have met with this form not unfrequently along the whole
Norwegian coast, from the upper part of the Christiania Fjord to Vadsg, in
moderate depths. All the specimens have been taken in the free state among
dredged material, and, though the parasitic habits of the animal are proved by
the structure of the oral parts, we do not as yet posess any information as to
what kind of invertebrate animals are at times infested by it.

Distribution.—British Isles (Brady), Spitsbergen (G. O. Sars), Franz
Joseph Land (Scott), ? Gulf of Naples (Giesbrecht).

Gen. 20. Rhynehomyzon, (Giesbrecht, 1895.

Generic Characters.—Body more slender than in the preceding genera,
with the anterior division far less expanded, and some of the trunk-segments
acutely produced laterally. Rostrum large and prominent, curved downwards.
Tail comparatively slender, consisting in female of 4, in male of 5 segments.
Caudal rami more or less produced. Anterior antenne of moderate length, and
composed of a varying number of articulations; those in male imperfectly hinged
and without any supplementary sensory filaments. Posterior antenne resembling
in structure those in Dermatomyzon. Oral cone short and massive, not prolonged
in any siphonal tube. Mandibles with the masticatory part more or less cultri-
form; palp very small, uniarticulate. Maxille and maxillipeds about as in Der-
matomyzon. Natatory legs well developed, and on the whole normally built.
Last pair of legs comparatively small, biarticulate, distal joint of somewhat dif-
ferent shape in the different species.

Remarks.—This_ genus, established by Giesbrecht, differs conspicuously,
as to the external appearance of the body, from the preceding ones, though in
the structural details approaching somewhat the genus Dermatomyzon. One of
the most conspicuous external characters is the very large and prominent falci-
form rostrum, which indeed has given rise to the generic name proposed by
Giesbrecht. The genus comprises as yet 3 well-defined species, 2 of which will
be described below, the 3rd species, R. falco Giesbrecht, being hitherto only
known from the Gulf of Naples.

13 — Crustacea.

98

57. Rhynchomyzon purpuroeinctum, (Scott).
(Pl. LXI).

Cyplopicera purpurocincta, Scott. Eleventh Ann. Rep. of the Fishery Board for Scotland, Part ITI
p. 209, Pl. III, figs. 29—40

Specific Characters.— Female. Anterior division of body rather strongly
vaulted above, and oblong oval in outline, greatest width scarcely exceeding half
the length. Cephalic segment large, being fully twice as long as the 4 succeeding
segments combined, aud having the frontal edge narrowly arched, epimeral edges
of the segment evenly curved in front and strengthened behind by a number
of transverse chitinous stripes. Rostrum very conspicuous in the lateral aspect
of the animal, and produced to a sharp point. Epimeral parts of the 2 succeeding
segments terminating behind in acute corners. Tail about equalling in length
*/; of the anterior division; genital segment almost cylindric in form, with a very
slight angular prominence on each side of the anterior part; 2nd segment almost
as long as the 2 succeeding segments combined; anal segment the smallest. Caudal
rami rather produced, somewhat exceeding in length the last 2 segments com-
bined, and slightly divergent, outer edge smooth, inner finely ciliated; apical sete
comparatively short, the innermost but one scarcely exceeding twice the length
of the corresponding ramus. Anterior antenne rather narrow, but much shorter
than the cephalic segment, and composed of 16 joints only, 2nd joint the largest
and apparently formed by the fusion of 4 short joints; terminal part biarticulate.
Posterior antenne with the penultimate joint scarcely half as long as the pre-
ceding one; apical spine rather slender. Oral cone very massive and rather
prominent below; anterior lip terminating in a somewhat curved point. Mandibles
with the masticatory part pronouncedly knife-shaped and minutely denticulate
inside the tip. Maxille with the outer lobe nearly as long as the inner, but
much narrower, linear in form; sete on both lobes comparatively short. Max-
illipeds moderately strong. Natatory legs exhibiting a similar armature to that
in Dermatomyzon nigripes. Last pair of legs with the distal joint oval in form
and subtruncate at the extremity, which carries 2 thin bristles between which
a somewhat larger lanceolate spine is attached; posterior edge of the joint finely
ciliated and having on each side of the innermost bristle a slight dentiform
projection,

Male much smaller than female, but not very different in the general
form of the body. ‘Tail, however, somewhat more slender and composed of 5
well-defined segments, the foremost of which (the genital segment) is compara-

tively smaller than in most other forms of the present section. Anterior

antennse very imperfectly hinged and composed of only 14 joints. Last pair of
legs differing from those in female by the presence on the distal joint of 3
additional spines attached to the inner edge.

Body in both sexes of a whitish colour, with a broad dark purplish, or
almost black band across the posterior part of the trunk, occupying the whole
of the 2nd, 3rd and 4th segments. Rostrum of a similar colour, and the
anterior antenne, the natatory legs, and the ends of the caudal rami also
more or less dark in colour.

Length of adult female amounting to 1.03 mm.,, of male to 0.73 mm.

Remarks.—This is a very distinct and easily recognisable form. It was
at first recorded by Scott as a species of the genus Cyclopicera Brady, but was
subsequently justly removed from that genus by Giesbrecht, and referred to his
new genus Rhynchomyzon. The present species may be regarded as the type of
that genus.

Occurrence.—I have only met with this form quite occasionally at Aale-
sund and Christiansund, west coast of Norway. The specimens were found in
moderate depths among dredged material.

Distribution.—British Isles (Scott), Gulf of Naples (Giesbrecht).

58. Rhynchomyzon rubrovittatum, G. O. Sars, n. sp.
(Pl. LXI).

Specific Characters.—Female. Anterior division of body less strongly
vaulted above than in the preceding species, and, viewed dorsally, of a some-
what irregular oblong oval form. Cephalic segment not quite twice as long as
the 4 succeeding ones combined, and narrowly rounded in front, epimeral edges
of the segment evenly curved. Rostrum very large, falciform, and terminating
in an acuminate point. Antepenultimate trunk-segment produced on each side
to a prominent acute process pointing obliquely backwards; penultimate segment,
as usual, much smaller, with the lateral parts broadly rounded; last segment
scarcely broader than the genital segment. Tail exceeding somewhat in length
*/3 of the anterior division; genital segment slightly dilated in front and produced
on each side to a spiniform, posteriorly pointing process; the succeeding segments
gradually diminishing in size, and, combined, about the length of the genital one.
Caudal rami rather produced, exceeding in length the last 2 segments combined,
and somewhat divergent, outer edge perfectly smooth and produced at the end

to a well-marked dentiform projection, inner edge finely ciliated; apical setee com-

100

paratively short. Anterior antenne very slender, almost attaining the length of
the cephalic segment, and composed of 20 joints, terminal part comparatively
small and, as in the preceding species, biarticulate. Posterior antenne about as
in that species. Oral cone very short and abruptly contracted at the extremity.
Mandibles with the masticatory part less strong than in the type species, and
scarcely denticulated at the tip. Maxillee with both lobes comparatively shorter.
Anterior maxillipeds with the claw imperfectly biarticulate. Posterior maxillipeds
rather slender, with a thin bristle in the middle of the palmar edge. Natatory
legs with the spines of the outer ramus rather broad, lancet-shaped and distinctly
denticulated at the edges; terminal joint of this ramus in Ist pair with only 2
setee inside, that of 2nd pair with 4 such sete. Last pair of legs with the distal
joint rather short and projecting into 2 unequal dentiform processes, between
which 2 likewise unequal bristles are attached.

Colour rather peculiar: anterior division of body of a clear whitish hue,
with a number of narrow transverse bands of a bright red colour, 3 of them
occupying the hindmost part of the 3 anterior segments, 2 others, of a more
irregular form, crossing the cephalic segment in front of the middle. ‘Tail and
anterior antenne of a beautiful rosy hue.

Length of adult female about 1 mm.

Male unknown.

Remarks.—This form is at once distinguishable from both of the 2 hitherto
recorded species, though evidently belonging to the same genus. The specific
name is derived from the very peculiar and beautiful colour of the body, when alive.

Occurrence.—Only a solitary female specimen of this handsame form has
come under my notice. It was taken, many years ago, at Kallevaag, west coast

of Norway, from a depth of about 50 fathoms, among dredged material.

Gen. 21. Collocheres, Canu, 1893.

Syn: Cyclopicera, Brady (part).
Clausomyzon, Giesbrecht.

Generic Characters.—Body of very slender form, with the anterior division
only slightly dilated and somewhat compressed in front; rostrum comparatively
small, but acutely produced. Epimeral parts of the trunk-segments rounded off.

Tail composed in female of 4, in male of 5 segments, Caudal rami long and

LOL

narrow, with the outermost seta more or less remote from the apex Anterior
antenne slender, resembling in structure those in the genus Ascomyzon, though
having the proximal and distal portions less sharply marked off from each other;
those in male distinctly hinged. Posterior antenne of normal structure. Oral
cone not much prolonged, pyriform in shape. Mandibles with the masticatory
part moderately slender; palp small, uniarticulate. Maxille with the outer lobe
much narrower than the inner, and tipped with only a single seta. Maxillipeds
comparatively slender; claw of the anterior ones distinctly biarticulate. Natatory
legs with the rami rather narrow; their armature about as in Dermatomyzon.
Last pair of legs with the distal jot more or less prolonged.

Remarks.—This genus was established in the year 1893 by Canu, to
include the species recorded by Brady as Cyclopicera graclicauda. Another
nearly-allied species has been described by Giesbrecht from the Gulf of Naples
under the name of C. Canui, and a 3rd species, C. elegans, has been added by
A. Scott. The last-named species differs however in some points so much from
the other two, that I have felt justified in removing it to a separate genus ‘To

the Fauna of Norway only belongs the type species, to be decribed below.

59. Collocheres gracilicauda, (Brady).
(Pl. LXII).

Cyplopicera gracilicauda, Brady, Monogr. British Copepoda, Vol. III, p. 58, Pl. LXXXITI,
figs. 1—10,
Syn: <Ascomyzon comatule, Rosoll.
Clausomyzon gracilicauda, Giesbr.

Specific Characters.—Female. Anterior division of body, viewed dorsally,
regularly oblong oval in outline, with the greatest width about equalling half the
length. Cephalic segment large and very deep, the epimeral edges being angu-
larly curved in the middle; rostrum not very large, but distinctly prominent below,
and acutely pointed. Last trunk-segment very small, scarcely broader than the
genital segment. ‘Tail slender and elongated, being not much shorter than the
anterior division; genital segment large and somewhat dilated in the middle; the
3 succeeding segments gradually diminishing in size. Caudal rami exceedingly
long and narrow, almost attaining half the length of the tail, and slightly divergent,
both edges smooth; outermost apical seta short, spiniform, and, together with
the dorsal bristle, somewhat remote from the apex, which projects outside to a
short dentiform process; inner mediate seta scarcely exceeding in length the

corresponding ramus, Anterior antenne almost as long as the cephalic segment,

102

and composed of 20 joints, terminal part biarticulate. Posterior antenne with
the penultimate joint scarcely more than half as long as the preceding one; rudi-
mentary outer ramus remote from the end of the latter joint, being attached
nearly at the middle of its posterior edge. Oral cone extending only to the insertions
of the posterior maxillipeds, and gradually tapered. Mandibles with the mas-
ticatory part moderately slender, and distinctly denticulated inside the tip; palp
with only a single apical seta. Maxille with the outer lobe a little shorter than
the inner, and much narrower, apical seta rather elongated and accompanied by
a small hair. Claw of anterior maxillipeds very slender and distinctly subdivided
in the middle, outer part evenly curved. Posterior maxillipeds, as usual, more
elongated than the anterior ones. Natatory legs of rather feeble structure, the
rami, especially in the 4th pair, being unusually narrow. Last pair of legs with
the proximal joint well defined from the segment, and produced inside to an
acuminate process; distal joint very long and slender, sabre like, and extending
far beyond the middle of the genital segment, outer edge produced, at some
distance from the end, to a dentiform projection, the apical part, beyond the
process, being provided with 3 or 4 small bristles.

Male, as usual smaller than female, and of still more slender shape.
Anterior antenne composed of 19 joints, the last 2 of which admit of being bent
upon the adjoining part. Last pair of legs differing somewhat from those in
female, the distal joint being comparatively shorter and almost claviform in
shape, and ‘moreover provided with 2 additional blunt spines inside. Genital
lobes bipartite.

Body in both sexes very pellucid and nearly colourless,

Length of adult female amounting to 0.85 mm., of male to 0.68 mm.

Remarks.—As mentioned above, this form was first described by Brady
as a species of his genus Cyclopicera. It was subsequently justly removed from
that genus by Canu and placed in the new genus Collocheres established by that
author. According to the same author, the Ascomyzon comatule of Rosoll is
identical with the present species.

Occurrence.—I have hitherto only met with this form in a single locality,
viz., at Risgr, south coast of Norway, where a few specimens were taken from a
depth of about 30 fathoms among dredged material. Rosoll found this form
parasitic on Comatula mediterranea.

Distribution.— British Isles (Brady), coast of France (Canu), Triest (Rosoll),
Gulf of Naples (Giesbrecht).

FADS:

Gen. 22. Mesocheres, Norm. & Scott, 1905.

Generic Characters.—Body slender and elongated, with the anterior
division only. slightly dilated. Cephalic segment less deep than in Collocheres
with the rostrum comparatively small. Epimeral parts of the trunk-segments
slightly produced. ‘Tail slender, and composed in female of only 3 segments.
Caudal rami long and narrow. Anterior antenne slender, resembling in structure
those in Ascomyzon. Posterior antenne moderately strong, with the penultimate
joint comparatively short. Oral cone very little produced. Mandibles with the
masticatory part comparatively short, tapered and minutely denticulated inside
the tip; palp small, uniarticulate. Maxille with the lobes likewise rather small,
the inner one being the larger. Anterior maxillipeds distinguished by the pre-
sence of a secondary spine at the base of the claw. Posterior maxillipeds of
normal structure. Natatory legs rather strongly built, with the spies unusually
broad, dagger-like. Last pair of legs very small, biarticulate, distal joint tri-
angular in shape.

Remarks.—With regard to the general form of the body and the long and
narrow caudal rami, this genus somewhat recalls the preceding one, from which
it is, however, at once distinguished by the different segmentation of the tail, in
which respect it agrees with the genus <Ascomyzon. In the other structural
details also, several peculiarities are found to exist, fully justifying the establish-
ment of the present genus. It comprises as yet only a single species, to

be described below.

60. Mesocheres anglicus, Norm. & Scott.
(Pl. LXIV).

Mesocheres anglicus, Norm. & Scott, Crustacea Copepoda new to science, Ann. & Mag. Nat. Hist.
Ser. 7. Vol. XV, p. 298.

Specific Characters.—Female. Anterior division of body oblong oval in
outline, with the greatest width about equalling half the length. Cephalic seg-
ment large and narrowly rounded in front, epimeral edge gently curved; rostrum
acutely produced below. Lateral parts of the 3 succeeding segments somewhat
angular behind. Last segment very small, scarcely broader than the genital
segment. Tail somewhat shorter than the anterior division, and very narrow;

genital segment about the length of the other 2 combined, and slightly dilated

104

in its anterior part, which projects on each side to a hamiform, posteriorly-
pointing process; anal segment much smaller than the preceding one. Caudal
rami exceedingly long and slender, linear, attaining about the length of the
remaining part of the tail, and only very slightly divergent; outer edge very
finely ciliated, inner smooth, tip transversely truncated; apical sete comparatively
short, the innermost but one scarcely longer tban the corresponding ramus.
Anterior antenne not quite as long as the cephalic segment, and composed of
21 well-defined joints, terminal part distinctly 3-articulate. Posterior antenne
with the penultimate joint scarcely half as long as the preceding one; rudimentary
outer ramus attached close to the end of the latter joint. Oral cone very short,
almost globular in form, its extremity being obtusely blunted and only extending
to the insertions of the anterior maxillipeds. Mandibles and maxille pointing
almost straight inwards. Anterior mavxillipeds with the claw rather slender and
evenly curved in its outer part, basal spine rather strong and likewise curved.
Posterior maxillipeds comparatively slender. Natatory legs with the number of
setee about as in Ascomyzon; spines distinguished by their broad dagger-like forin
and the coarse denticulation of their edges. Last pair of legs with the proximal
joint well defined and of the usual appearance, distal joint rounded triangular
in form and provided with 2 small apical bristles and 2 lateral ones, that
of the outer edge the longer. Ovisacs, in the specimen examined, very small,
each containing only 3 ova, arranged in a single row.

Body of a clear whitish colour, partly tinged with reddish orange; ovarial
tubes dark green.

Length of adult female about 1 mm.

Male unknown.

Remarks.—This form was first anounced under the above name by
Norman & Scott in the year 1905 from a single female specimen taken
in Plymouth Sound. In the following year this specimen was redescribed
and figured in detail by the same authors in their work on the Crustacea of
Devon and Cornwall.

Occurrence.—Only a few female specimens of this form have hitherto
come under my notice. They were taken, many years ago, in the upper.
part of the Christiania Fjord from a depth of about 30 fathoms among dredged
material.

Distribution.—British Isles (Norman & Scott).

Copepoda

Pin EX

Cyclopoida

Cyclopidz

GO Sars, del:

Platycyclops affinis, G. O. Sars

Copepoda

Cyclopoida

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Ascomyzon asterocheres, Boeck
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Copepoda

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Ascomyzon Lilljeborgi, Thorell

Copepoda

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Ascomyzon Boecki, (Brady)

Copepoda

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Cyclopoida

Ascomyzontidz

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Ascomyzon simulans, Scott

Ascomyzontidz

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Ascomyzon latum, (Brady)

Copepoda

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Cyclopoida Pl.

Ascomyzontide

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Ascomyzon parvum, (Giesbrecht)

Copepoda

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Echinocheres violaceus, Claus

Copepoda

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Dermatomyzon nigripes, (Brady)

Copepoda

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Ascomyzontidze

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Dermatomyzon nigripes, (Brady)

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Gen. 23. Leptomyzon, G. O. Sars, n.
Syn: Collocheres, A. Scott (part).

Generic Characters.—Body slender, with the anterior division very little
dilated. Cephalic segment with the inferior edges considerably curved in front;
rostral projection very slight and obtuse at the tip. Epimeral plates of the
succeeding segments rounded off. Tail very slender, and composed in female of
4 well-defined segments; genital segment without any lateral projections. Caudal
rami somewhat produced, though far less slender than in the 2 preceding genera,
outer seta more or less remote from the apex, dorsal bristle, however, occupying
its usual place near the end of the ramus. Anterior antenne slender, with the
full number of articulations. Posterior antennz resembling in structure those in
Collocheres. Oral cone short and stout, carrying at the obtuse apex 2 remark-
able diverging tentacular appendages, apparently attached to the posterior lip.
Mandibles rather strong, with the apex distinctly denticulate, palp small, con-
sisting of a narrow cylindrical joint, carrying on the tip a ciliated seta. Maxille
with the inner lobe well developed and furnished at the end with 4 rather strong
setae; outer lobe much narrower, but of about the same length, and provided with
only a single apical seta. Maxillipeds with the dactyli extremely slender, that of the
anterior ones distinctly biarticulate. Natatory legs well developed, with the rami
comparatively broader than in Collocheres; their armature about as in that genus.
Last pair of legs distinctly biarticulate, proximal joint forming inside a lingui-
form expansion, distal joint rather large, oblong, and extending backwards along
the genital segment.

Remarks.—The present new genus is established to include the form
described by A. Scott as Collocheres elegans. This form, it is true, exhibits some
characters in common with the type of the genus Collocheres, but differs in other
particulars so materially, that in my opinion it ought to be kept apart as the
type of a distinct, though nearly-allied genus. The chief differences are found
in the structure of the oral cone, the last pair of legs and the caudal rami. In
addition to the type species described below, the form recorded by A. Scott

from Ceylon as Collocheres Giesbrechti is undoubtedly referable to the present genus.

61. Leptomyzon elegans, (A. Scott).
(Pl. LXV).
Collocheres elegans, A. Scott, Report for 1895 of the Lancashire Sea-Fisheries Laboratorium,
Tees, ele Ven ors, Gey,
Specific Characters.—Female. Body exceedingly slender and elongated,

with the anterior division oblong fusiform in outline, greatest width scarcely

14 — Crustacea.

106

exceeding half the length. Cephalic segment somewhat longer than the 4 suc-
ceeding segments combined, and narrowly rounded in front. Tail slender, almost
attaining the length of the anterior division; genital segment rather large,
exceeding in length the 3 succeeding segments combined, and slightly dilated in
its anterior part. Caudal rami rather produced, being about the length of the
last 2 segments combined, and somewhat lamellar, with the outer part slightly
narrowed, inner edge finely ciliated; outermost seta at a considerable distance from
the apex, and attached to a distinct ledge on the exterior margin, innermost seta
slender, exceeding the corresponding ramus in length; the inner mediate one
about half the length of the tail. Anterior antenne nearly as long as the
cephalic segment, and composed of 21 joints, the outer 3 constituting the ter-
minal part. Posterior antennze with the outer ramus very small and attached
about in the middle of the very slender 2nd joint. Natatory legs of a similar
structure to that in Collocheres gracilicauda, but more strongly built, especially
the 4th pair. Last pair of legs scarcely extending beyond the middle of the
genital segment; inner expansion of proximal joint obtusely triangular in form,
unarmed; distal joint oblong oval in form, with the inner edge straight, outer
gently curved and minutely ciliated, tip obliquely truncated and provided with
3 small bristles.

Body rather pellucid, of a whitish grey colour.

Length of adult female 0.87 mm.

Male unknown.

Remarks.—This form, as already mentioned, was described by A. Scott
as a species of the genus Collocheres, the characteristic structure of the oral tube
having escaped his attention, as also the difference in the arrangement of the
caudal sete.

Occurrence.—A few female specimens of this form were collected, many
years ago, at Eggesbones, west coast of Norway, from a depth of about 20 fathoms.

Distribution.— Off Port Erin, west coast of Scotland (A. Scott).

Gen. 24. Seottocheres, Giesbrecht 1897.

Syn: Acontiophorus. Scott (part).

Generic Characters.—Body of a similar slender form to that in the 3
preceding genera, the anterior division being only slightly dilated. Cephalic

segment scarcely compressed, its inferior edges being quite evenly curved; rostrum

107

wholly absent. Epimeral parts of the 3 succeeding segments rounded oft.
Tail composed in female of only 3, in male of 4 segments. Caudal rami not
much produced, in some cases very short, with all the sete originating from the
end. Anterior antennee resembling in structure those in the other Ascomyzontide,
though having the number of joints somewhat reduced; those in male distinctly
hinged and provided with supplementary esthetasks. Posterior antenne of the
usual appearance. Oral cone, however, rather peculiar and somewhat similar to
that in the next family, being produced into a very narrow, more or less curved
siphonal tube. Mandibles without any palp, and having the masticatory part
extremely slender, setiform. Maxille with the lobes very unequal in size, each
carrying 3 sete. Maxillipeds comparatively slender, with the dactyli exceedingly
narrow, that of the anterior ones distinctly biarticulate. Natatory legs well
developed, with the rami comparatively broad and equal-sized; their armature
differing slightly from that in the other genera. Last pair of legs of moderate
size, biarticulate, proximal joint broadly expanded inside, distal joint lamelliform.

Remarks.—This genus was established by Giesbrecht, to include the
form at first described by Scott as Acontiophorus elongatus. The differences of
this form from the true Acontiophori have been duly pointed out by Giesbrecht.
Indeed, the only character by which it seems to approach that genus, is the
structure of the siphon. Otherwise it agrees fairly well with the other Ascony-
zontide, and of course ought to be included in that family as here defmed. In
‘addition to the type species described below, Giesbrecht records another nearly-

allied form from the Bay of Naples under the name of S. longifurea.

62. Scottocheres elongatus, (Scott).
(Pl. LXVI).

Acontiophorus elongatus, Scott, Ann. & Mag. Nat. Hist., Ser. 6, Vol. XII, p. 145, PL IX,
figs. 15—20.

Specific Characters.—Female. Body comparatively narrow and elongated,
with the anterior division oblong in form, greatest width scarcely exceeding half
the length. Cephalic segment of moderate size and obtusely rounded in front,
without any trace of a rostral projection below. The 3 succeeding segments
gradually diminishing in size, with the epimeral parts not very prominent. Tail
scarcely exceeding half the length of the anterior division; genital segment com-
paratively large, occupying more than half the length of the tail, and somewhat
dilated in its anterior part, with a slight prominence on each side, just in front

of the genital orifices; anal segment very small, scarcely half as long as the

preceding segment. Caudal rami short, quadrangular in form, being scarcely
longer than they are broad, and transversely truncated at the end; apical sete
of moderate length, the outer mediate one remarkably thickened in its middle
part. Anterior antenne not nearly attaining the length of the cephalic segment
and rather narrow, being composed of 17 joimts sparingly clothed with com-
paratively small sete, proximal division well marked off from the distal one,
terminal part uniarticulate. Posterior antenne with the 2nd (basal) joint
rather slender, rudimentary outer ramus attached near the end of this joint;
terminal joint very small, but with the apical spine rather strong. Siphon
extending about to the end of the anterior division of the body, being,
as a rule, conspicuously curved, and in preserved specimens often split up into
its two components, the anterior and posterior lips. Ist pair of natatory legs
with the spine, issuing from the 2nd basal joint inside, lanceolate in form; terminal
joint of outer ramus with only 2 sete inside, distal spine of outer edge well
developed, the other 2 very small. Same joint in 2nd and 8rd pairs with 4, in
4th pair with 3 sete inside. Terminal joint of inner ramus in Ist pair with a
conspicuous dentiform projection inside the tip; same joint in 4th pair with only
a single apical spine. Last pair of legs with the inner expansion of proximal
joint broadly rounded, unarmed; distal joint oval in form, with the edges
minutely ciliated and the tip provided with 3 comparatively short sete, the middle
one spiniform.

Male resembling the female in the general shape of the body, but of
smaller size, and having the tail composed of 4 well defined segments, the 1st
of which is considerably swollen, to receive the comparatively large globular
spermatophores. Anterior antennse much more powerfully developed than in
female, though composed of a smaller number of joints, viz., 15, the last 2 of
which form together a movable terminal section, which admits of being bent
‘upon the somewhat thickened adjoining part of the antenna.

Body (in female) rather pellucid, with a faint orange tinge, and with
the translucent ovarial tubes of a somewhat darker hue.

Length of adult female about 1 mm., of male 0.70 mm.

Remarks.—This form, as mentioned above, was at first described by Scott
as a species of the genus Acontiophorus, apparently on account of the somewhat
similar structure of the siphon. Its generic difference has however subsequently
been admitted by that author, and it was redescribed under the above name in
the sixteenth Annual Report of the Fishery Board for Scotland. From the
nearly-allied Neapolitan species, S. longifurca Giesbr., it is easily distinguished

by the very short caudal rami.

109

Occurrence.—A few female specimens of this form were collected, many
years ago, at Eggesbones, west coast of Norway, and some additional specimens,
among them a single male, were recently picked up from the residue of the
same collecting bottle, in which, as mentioned above, several species of Ascomyzon
were found.

Distribution.— British Isles (Scott), Bay of Naples (Giesbrecht), Ceylon
(A. Scott).

Fam. 5. Acontiophoride.

Characters.—General form of body resembling that in the Ascomyzontide,
the anterior division being more or less dilated, the posterior one attenuated.
Anterior antenne not much produced, and densely clothed with partly ciliated
setae, no distinct boundary being found, as in most of the Ascomyzontidw, between
the proximal and distal portions; a small terminal part, however, distinguishable,
formed by the outermost joints succeeding that carrying the usual esthetask.
Posterior antenne rather unlike those in the Ascomyzontide, the terminal joint
being much more fully developed and provided with several spines and sete;
outer ramus comparatively large, though uniarticulate. Oral cone produced into
a very narrow siphonal tube somewhat resembling that in Scottocheres. Mandibles
with the masticatory part imperfectly developed, terminating in a simple hair-
like poimt, which does not extend to the end of the tube; palp replaced by a
single very large and densely plumose seta. Maxillze with the basal part unusu-
ally large and massive, lobes more or less curved downwards and provided with
richly ciliated setz. Maxillipeds of the usual structure. Natatory legs Jikewise
on the whole normally built. Last pair of legs comparatively small, with the
proximal joint imperfectly defined; distal joint scarcely lamellar, and provided
with several spiniform setze.

Remarks.—This family is established to include the genus Acontiophorus
of Brady, which seems to me to differ im some respects so materially from the
preceding genera comprised within the family Ascomyzontide, that it can hardly
be associated with them. ‘The structure of the posterior antenne and the oral
parts, in particular, is very unlike that found in the true Ascomyzontide. I am
inclined to believe that the 2 hitherto known species, A. suctatws and ornatus,
should more properly be regarded as types of 2 nearly-allied genera, as their

outward appearance is rather dissimilar, and some of the structural details also

pate

seem to exhibit differences of more than specific value. In any case, the species
described below, as the first one recorded, ought to be regarded as the type of

the genus Acontiophorus.

Gen. 25. ACOntiophorus, Brady 1880.

Syn: Solenostoma, Brady (preoccupied).

Generic Characters.— Anterior division of body moderately dilated, not
depressed. Epimeral parts of the trunk-segments not produced, but evenly rounded
off. Tail composed in female of 3, in male of 4 segments, none of them pro-
duced at the postero-lateral corners. Caudal rami of moderate size, and trans-
versely truncated at the end, apical sete well developed. Anterior antenne very
short, with the number of joints considerably reduced; those in male imperfectly
hinged, and provided with supplementary esthetasks. Posterior antennze with the
terminal joint rather large and scarcely narrowed distally, outer ramus attached
close to the end of the 2nd (basal) joint, and cylindrical in form. Siphon
exceedingly slender and elongated. Maxille with the inner lobe larger than the
outer, and carrying on the tip 4 sete, the 2 inner of which are densely plumose.
Maxillipeds quite normal. Natatory legs with the rami comparatively slender and
subequal in length; their armature resembling that in the gen. Scottocheres. Last
pair of legs very small; distal joint provided with 5 rather unequal sete.

Remarks.—The above-given generic diagnosis chiefly refers to the type
species A. scutatus. The other species referred to this genus, A. ornatus, differs
more or less in some of the characters here ‘given, and should in my opinion,

as noted above, more properly be removed to a separate, though closely-allied genus.

63. Acontiophorus scutatus, Brady.
(Pl. LXVII).
Acontiophorus scutatus, Brady, Monogr. of British Copepoda, Vol. III, p. 69, Pl. XC, figs. 1—10.

Syn: Solenostoma scutatum, Brady & Roberts.

Specific Characters—Female. Body moderately slender, obpyriform in
shape, with the anterior division broadly ovate, greatest width considerably ex-
ceeding half the length. Cephalic segment very large, occupying nearly half the
length of the body, and quite evenly rounded in front; rostral projection extremely
small, almost obsolete. Tail scarcely exceeding in length 1/; of the anterior

i

division and having all the segments quite simple; genital segment about the
length of the 2 succeeding segments combined and _ slightly dilated in front.
Caudal rami sublinear in form, being about 3 times as long as they are broad,
and scarcely at all divergent; apical setee more or less curved outwards in their
distal part, the inner mediate one exceeding the tail in length. Anterior antenne
short and rather thick at the base, tapering distally, and composed of only 11
joints clothed with slender spreading sete, Ist, 2nd and 6th joints larger than
the others; terminal part 3-articulate. Posterior antenne fully as long as the
anterior ones, and having the 2nd (basal) jomt comparatively large and slightly
curved in the middle, terminal joint exceeding somewhat in size the preceding
one, and carrying on the blunted end 2 comparatively large spines of unequal
length and finely denticulated on the edges, these spines being moreover accom-
panied inside by a slender ciliated seta, and outside by a somewhat shorter
seta and a minute bristle; outer ramus somewhat longer than the terminal joint
and provided with a long apical seta and another much shorter lateral one.
Siphonal tube exceedingly long and slender, extending almost to the end of the
body. Maxille with the outer lobe originating far in front and considerably
curved, carrying on the tip 3 moderately long plumose sete accompanied outside
by a minute bristle. Maxillipeds moderately strong, dactylus of the anterior ones
only slightly curved and imperfectly subdivided in the middle; basal part of the
posterior ones composed of 2 well-defined joints. Natatory legs with the spines
of the outer ramus narrow lancet-shaped; terminal joint of this ramus in Ist and
4th pairs with 3 sete inside; terminal joint of inner ramus in 3rd and 4th pair
with only a single spine on the tip. Last pair of legs with the distal joint
rather small, rounded oval in form, and carrying inside 2 short sete, outside 2
much longer sete attached close together to a distinct ledge and partly crossing
each other, and at the somewhat exserted tip another similar seta. Ovisacs
oblong in form, and closely appressed to the tail, each containing a rather
limited number of ova, in some cases only 4 arranged in a single row.

Male considerably smaller than female, and exhibiting the usual sexual
differences. Anterior antennse composed of the same number of joints as in the
female, though their mutual relation is rather different; terminal part consisting
of only a single narrow lamellar joint; esthetask issuing from the preceding
joint very largely developed.

Colour (in female) generally light yellowish brown, with darker intestine
and ovarial tubes.

Length of adult female about 1 mm.

112

Remarks.—This form was at first recorded by Messrs. Brady and Robertson
under the name of Solenostoma scutatum. The generic name being however
preoccupied, it was redescribed and figured by the former author in his
monograph under the above name. It is a very distinct and easily recognizable
form, especially distinguished by the unusually short anterior antenne and the
extraordinary development of the siphon.

Occurrence.—I have met with this form in 2 different localities on the
west coast of Norway, viz., at Kalvaag and Aalesund. In the latter place it
occurred not unfrequently at a depth of about 10 fathoms among alge and
other marine growths.

Distribution.—British Isles (Brady), coast of France (Canu), Mediter-
ranean (Claus, Giesbrecht).

Fam. 6. Myzopontiide.

Characters. —General form of body resembling that in some of the Asco-
myzontide, being comparatively slender, with the anterior division moderately
broad, and the cephalic segment scarcely projecting at the postero-lateral cor-
ners. Tail rather produced and of quite normal appearance, being composed in
female of 4, in male of 5 segments. Anterior antenne slender, with the number
of joints somewhat reduced; terminal part not defined, the usual esthetask
issuing from the last joint, near the tip. Posterior antennz comparatively small,
but with the terminal joint more developed than in the Ascomyzontide, outer
ramus rudimentary. Oral cone more or less produced. Mandibles without
any palp. Maxille and maxillipeds on the whole normal. Natatory legs
resembling in structure those in the Ascomyzontida. Last pair of legs with
the proximal joint imperfectly defined from the segment, distal joint very small
or of moderate size.

Remarks.—This is another family, which I have found it necessary to
establish in order to include the 2 genera Myzopontius and Neopontius, the
systematic position of which has appeared rather doubtful. Giesbrecht refers both
these genera to his sub-femily Dyspontiine, apparently on account of the somewhat
similar structure of the anterior antenne; but in other respects they differ very
conspicuously from the true Dyspontiine, both as regards the outward appearance of

the body and the structural details, while on the other hand they exhibit, several

characters in common, as indicated in the above diagnosis. As the genus
Myzopontius was the first established of the two, the name of the family must be

derived from that genus.

Gen. 26. Myzopontius, Giesbrecht, 1895.

Generic Characters.—Anterior division of body moderately dilated, with
the cephalic segment comparatively large, and the epimeral parts of the trunk-
segments only slightly angular. Tail slender, though not much elongated. Caudal
rami moderately produced. Anterior antennz slender and only sparingly seti-
ferous; those in male distinctly hinged, and provided with supplementary zesthe-
tasks. Posterior antenne likewise comparatively slender, with the penultimate
joint well defined and the terminal joint rather elongated. Oral cone produced
into a slender siphonal tube. Mandibles very narrow. Maxille with the inner
lobe shorter than the outer, and provided with only a single apical seta. Both
pairs of maxillipeds very slender. Terminal joint of outer ramus in Ist pair of
natatory legs with 3 sete inside; same joint in the 3 succeeding pairs with 5
sete. Last pair of legs very small.

Remarks.—This genus was established in the year 1895 by Giesbrecht,
to include a species found by him in the Bay of Naples. In the elaborate
monograph of the Asterocheride by the same author, this genus was placed at
the head of the sub-family Dyspontiine, and its differences from the more
typical genera, showing an approach to the Asterocherime (= Ascomyzontde),
were pointed out. The genus as yet only comprises a single species, to be

described below.

64. Myzopontius pungens, Giesbr.
(Pl. LXVIID).

Myzopontius pungens, Giesbrecht, Asterocheride, p. 106, Pl. 1, fig. 6, Pl. 6, figs. 1—l14.

Specific Characters.— Female. Body moderately slender, with the anterior
division oblong oval in outline, greatest width slightly exceeding half the length.
Cephalic segment very large, occupying almost half the length of the body, frontal
edge evenly curved, pleural parts incurved and rather broad; rostral projection
extremely small. The 3 succeeding segments gradually diminishing in size and

having the epimeral parts slightly angular behind. ‘Tail scarcely attaining half

15 — Crustacea.

the length of the anterior division and narrow cylindrical in form; genital segment
of moderate size, with the anterior part slightly dilated, forming on each side a
rounded prominence. Caudal rami slightly exceeding in length the anal segment
and sublinear in form, being scarcely at all divergent; outermost seta, together
with the dorsal bristle, slightly remote from the apex; middle apical seta of
moderate length. Anterior antennz slender, though scarcely exceeding half the
length of the cephalic segment, and composed of 12 joints, the last one much
the longest. Posterior antenne rather narrow, with the terminal joint consider-
ably produced, being almost as long as the 2nd (basal) joint, and carrying
3 apical and one lateral seta, middle apical seta much longer than the other 2,
lateral seta attached near the base. Siphon extending about to the end of the
cephalic segment. Maxille with the outer lobe rather narrow, sublinear in form,
and carrying on the tip 2 moderately long sete; inner lobe conical in form with
the apical seta very slender. Anterior maxillipeds with the dactylus exceedingly
narrow and elongated, distal part evenly curved and clothed inside with minute
spinules. Posterior maxillipeds with the hand unusually narrow, dactylus normal.
Natatory legs moderately strong, with the spines of the outer ramus finely
denticulate; 1st joint of inner ramus in Ist pair unusually broad and, like the
2nd basal joint, provided on the lower face with a rounded, boss-like prominence.
Last pair of legs extremely minute; distal joint provided with 3 small bristles,
one apical and 2 lateral.

Body, according to Giesbrecht, nearly colourless, with reddish orange
translucent intestine and lateral coeca; eye very large and bright red.

Length of adult female about 1 mm.

Remarks.—This Copepod resembles in its outward appearance certain
forms of the Ascomyzontide, but is easily distinguishable by the rather different
structure of the anterior antenne. The specific name proposed by Giesbrecht
alludes to the narrowly-produced siphon, which in some cases is seen projecting
from the body at nearly a right angle, as indicated in the side-view figure
given by Giesbrecht.

Occurrence.— A solitary, but well preserved female specimen of this form
was found in a sample taken at Korshavn, south coast of Norway, from a depth
of about 40 fathoms, muddy sand.

Distribution.—Bay of Naples (Giesbrecht), Franz Joseph Land (Scott).

115

Gen. 27. Neopontius, Scott, 1898.

Generic Characters.—Anterior division of body only slightly dilated, with
some of the segments angularly produced laterally. Cephalic segment of moderate
size and narrowed in front; rostral projection well marked. ‘Tail very slender,
with the genital segment in female long and narrow. Caudal rami rather pro-
duced and somewhat lamellar; apical sete comparatively short. Anterior antennze
of moderate size and densely clothed with slender, curved sete; those in male
imperfectly hinged and without any supplementary esthetasks. Posterior antennze
rather stout, with the 2 middle joints imperfectly defined in female, terminal joint
not much produced. Oral cone comparatively short, not being produced into a
siphonal tube. Mandibles less slender than in Myzopontius, and distinctly denti-
culated at the tip. Maxille with the inner lobe larger than the outer, and car-
rying at the tip 4 sete. Mavxillipeds comparatively strongly built, dactylus of
the anterior ones armed inside, at some distance from the end, with a very con-
spicuous curved secondary spine. Natatory legs of a similar structure to that
in Myzopontius. Last pair of legs, however, more fully developed, with the
distal joint rather produced and somewhat spatulate in form.

Remarks—This is a very distinct genus, exhibiting, as it does, several
well-marked differences from Myzopontius. Yet its affinity to that genus 1s
evidently closer than to any other of the siphonostomous Cyclopoida, and this

has also been recognised both by Scott and Giesbrecht.

65. Neopontius angularis, Scott.
(Pl LXIX).

Neopontius angularis, Scott, Sixteenth Annual Report of the Fishery Board for Scotland,
Part III, p. 271, Pl. XIV, figs. 1—11.

Specific Characters—Female. Body very slender, with the anterior
division oblong oval in outline and somewhat abruptly truncated behind. Cephalic
segment scarcely occupying more than !/; of the total length and narrowly rounded
in front; rostral projection well marked, but incurved, and acute at the tip. The
succeeding trunk-segments rather dissimilar both in size and form, the anterior one
being comparatively simple, whereas the 3rd segment is unusually broad, with
the epimeral parts prominent and triangularly pointed behind; penultimate seg-
ment much smaller, with the epimeral parts angularly rounded; last segment
very narrow. ‘Tail almost attaining the length of the anterior division and rather

narrow; genital segment longer than the 3 succeeding segments combined, and

116

widening slightly in front. Caudal rami exceeding in length the last 2 segments
combined and conspicuously lamellar, inner edge finely ciliated, outer edge exhi-
biting, somewhat beyond the middle, a distinct ledge to which the outermost seta,
together with the dorsal bristle, is attached; apical sete comparatively short, but
rather coarse and densely plumose. Anterior antennze somewhat exceeding half
the length of the cephalic segment, and composed of 12 joints, the 2nd of which
is rather large, being fully as long as the 4 succeeding joints combined; terminal
joint elongated, club-shaped. Posterior antenne comparatively short, but rather
stout, with the 2 middle joints confluent; terminal joint not much prolonged, and
carrying 4 elongated and finely ciliated sete, 3 apical and one lateral. Oral
cone extending only slightly beyond the insertion of the posterior maxillipeds,
and evenly tapered distally. Mandibles apparently biarticulate, and very finely
denticulate at the tip. Maxille with the ozter lobe scarcely more than half as
long as the inner, and carrying on the tip 2 moderately long sete. Anterior
maxillipeds with the distal part of the dactylus, as also the secondary spine,
finely denticulate inside. Posterior maxillipeds with the hand imperfectly defined
from the basal part; terminal part of the dactylus denticulate. Natatory legs
moderately strong, with the spines of the outer ramus dagger-like. Last pair
of legs with the distal joint well developed, sub-spatulate in form, and provided
with 3 sete, 2 issuing from the transversely truncated end, the 3rd from the
lower face at some distance from the apex; outer edge of the joint minutely
ciliated, inner projecting near the end to a dentiform process.

Male, as usual, smaller than female, and having the anterior division
of the body less angular in shape. Anterior antenne more strongly built, and
composed of 14 joints, those of the distal part conspicuously thickened, 10th
joint armed in front with 2 slender spines, apical joint small, rounded. Posterior
antenn with the 2 middle joints well defined; the posterior maxillipeds also
quite normally developed.

Colour (in female) yellowish grey, with scattered pigmentary patches of
an ochraceous hue on the dorsal face of the anterior division of the body.

Length of adult female 1.35 mm., of male 1.10 mm.

Remarks.—This is the only as yet known species of the genus, and may
easily be recognized by the peculiar angular shape of the anterior division of
the body, which, especially in the female, is very conspicuous and indeed has
given rise to the specific name proposed by Scott.

Occurrence.—I have long been acquainted with this peculiar form, of

which some few specimens were collected, many years ago, at Eggesbones, west

el ii.

coast of Norway, from a depth of about 20 fathoms. I have, however, not met
with it in other localities, and it thus seems to be of very rare occurrence.
Distribution.——Scottish coast (Scott).

Fam. 7. Dyspontiide.

Characters.—General form of body, as a rule, very broad and depressed,
with the anterior division much expanded. Cephalic segment large and arcuate
in front, with the postero-lateral corners produced, and the pleural parts very
broad, leaving in front only a narrow space for the insertion of the antenne and
oral parts. Epimeral parts of the trunk-segments forming well-defined lappets
projecting laterally. Last segment, however, as usual, not expanded and very
small. Tail comparatively short, and composed in female of 4, in male of 5
segments; genital segment much expanded in its anterior part. Anterior
antenne slender and narrow, with the number of joints more or less reduced,
last joint club-shaped and carrying near the end the usual esthetask; those
in male more or less distinctly hinged and provided with supplementary
esthetasks, Posterior antenne very small, 4-articulate, outer ramus rudimentary.
Oral cone generally much produced. Mandibles without any palp, masticatory
part slender styliform, extending to the end of the siphon. Maxille with both
lobes very narrow, the inner one the larger and generally provided with only a
single apical seta, outer lobe with 2 such sete. Both pairs of mavxillipeds very
fully developed. Natatory legs more or less incuryed, with the rami compara-
tively slender, the inner one in 4th pair more or less reduced, in some cases
wholly wanting. Last pair of legs extremely small and rudimentary, being only
represented by a minute knob-like joint accompanied outside by the usual seta.

Remarks.—The present family does not quite answer to the sub-family
Dyspontiine of Giesbrecht, in which the 2 preceding genera are also included,
as also 2 other genera which I have felt justified in removing, viz., the genera
Artotrogus and Dystrogus. In the restriction thus adopted, the family Dyspon-
tide forms a very natural group, comprising a number of genera, which agree
pretty well in the more essential characters. In addition to the 5 genera treated
of in the following pages, the 2 genera Pteropontius and Sestropontius, estab-
lished by Giesbrecht, belong to the present family, which thus at present comprises

no less than 7 different genera.

Gen. 28. Dyspontius, Thorell, 1859.

Syn: Gallopontius, Giesbrecht.

Generic Characters.—Auterior division of body broad and expanded,
with the epimeral lappets well marked; those of penultimate segment, however,
very small. Tail short, with the genital segment considerably expanded. Anterior
antenne in female generally 9-articulate, with the 2nd joint the largest. Siphon
rather strong, with the basal part only slightly dilated. Maxille with the lobes
not very unequal, the inner one carrying a single apical seta, the outer one 2 such
sete. Maxillipeds moderately slender. Natatory legs with the rami comparatively
narrow, terminal joint of outer ramus in Ist pair small, with only 2 spines out-
side and 2 sete inside. 4th pair of legs with the outer ramus well developed,
inner however wholly absent. Free joint of last pair of legs with only 2 apical
bristles.

Remarks.—This genus, the type of the present family, was established
in the year 1859 by Thorell, who placed it together with the genus Ascomyzon
within his family <Ascomyzontide. The genus Gallopontius, at first established
by Giesbrecht for a Neapolitan species, G. fringilla, was subsequently withdrawn
by that author and identified with Thorell’s genus. In addition to the above-
named species another Neapolitan species was described as D. passer.

The chief characters of the present genus are found in the form of the
siphon, the armature of the terminal joint of the outer ramus in the Ist pair of
legs, and the total absence of an inner ramus in the 4th pair. In the last-named
character it however agrees with 2 other genera, viz., Cryplopontius and Ptero-
pontius. To the fauna of Norway belongs only the type species, to be de-
scribed below.

66. Dyspontius striatus, Thorell.
(PINEKX):

Dyspontius striatus, Thorell, Bidrag til kiinnedomen om Crustaceer, som lefva i arter af slegtet
Wscidia. ip.) S15 Pl) KAW he 122:

Syn: Gallopontius rotundus, Giesbrecht.

Specific Characters.—Female. Body pronouncedly depressed, with the
anterior division broad and expanded, greatest width almost equalling the length.
Cephalic segment very large, occupying rather more than half the total length,
postero-lateral corners prominent, frontal part evenly rounded, without any dorsal
crest; pleural parts of the segment longitudinally striated. Epimeral lappets of

the 2 succeeding segments well developed, those of penultimate segment, however,

oe

very small. ‘Tail scarcely exceeding in length '/; of the anterior division; anterior
part of genital segment considerably expanded. Caudal rami comparatively short,
being only slightly longer than they are broad, outermost seta somewhat remote
from the apex, inner mediate one a little longer than the tail. Anterior antenne
about half the length of the cephalic segment, and composed of 9 joints, 2nd
jot the longest; terminal joint somewhat exceeding in length the 2 preceding
joints combined. Posterior antenne with the terminal joint about as long as
the preceding one; middle apical seta rather slender, the other 2 short. Siphon
comparatively strong and gradually tapered distally, extending somewhat beyond
the limits of the cephalic segment. Maxille with the inner lobe only slightly
longer than the outer and rather narrow, apical seta scarcely as long as the
lobe; apical sete of outer lobe rather slender. Anterior maxillipeds with the
dactylus very slender and elongated, terminating in a short, slightly curved claw,
and armed at some distance from this claw with a small secondary spine.
- Posterior maxillipeds normal. Natatory legs with the spines of the outer ramus
comparatively short, 2nd basal joint in 2nd—4th pairs angularly produced inside;
4th pair with the outer ramus fully as large as in the 2 preceding pairs and
armed in a similar manner; of an inner ramus not the slightest rudiment present.
Ovisacs globular in form.

Male considerably smaller than female, and having the anterior division
of the body less broad. Genital segment greatly swollen, to receive the 2 globular
spermatophores. Anterior antenne composed of 11 joints, and distinctly hinged,
the last 2 joints forming together a movable part, which admits of being bent
upon the adjoining part of the antenna; 8th joint somewhat dilated, and armed
in the middle of the anterior edge with a short spine.

Colour of female generally pale yellowish grey, with a few small reddish
spots on the cephalic segment; intestine and its distinctly lobular coeca of a
darker yellow hue.

Length of adult female amounting to 1.45 mm., of male to 1.10 mm.

Remarks.—This form was described by Thorell from a solitary female
specimen taken by Lilljeborg in the open sea, and was supposed by that author
to be, like Ascomyzon Lalljeborgi, an internal parasite of Ascidie. It has sub-
sequently been recorded in both sexes by several other authors, though in some
cases it appears somewhat doubtful, whether the descriptions in reality refer to
the present species or to some other nearly-allied form. The form at first
recorded by Giesbrecht from the Bay of Naples as Gallopontius rotundus has

subsequently been identified by that author with the present species. From the

190

other 2 Neapolitan species, D fringilla and D. passer, it is at once distinguished
by the different form of the cephalic segment and the absence of any frontal crest.

I have met with this characteristic form in many places of

Occurrence.
the Norwegian coast, from the Christiania Fjord up to Finmark (Hammerfest).
All the specimens have been taken free in the sea among alge and other marine
growths, and there is indeed little probability that this form ever, as supposed
by Thorell, has its abode within the branchial cavity of Ascidize.

Distribution.—Christineberg (Thorell), British Isles (Brady), coast of
France (Canu), Bay of Naples (Giesbrecht).

Gen, 29. Cryptopontius, Giesbr., 1899.

Generic Characters.—Anterior division of body less expanded and less
depressed than in Dyspontius, with the epimeral lappets more densely crowded
and curved backwards; those of penultimate segment very small, almost wholly
concealed. Tail short, but with unusually long apical sete. Structure of the 2
pairs of antenne about as in Dyspontius. Oral cone with the basal part con-
spicuously thickened and terminating in a very slender siphonal tube. Maxille
with the lobes rather unequal in length and very narrow; apical sete on both
lobes slender. Anterior maxillipeds with the dactylus exceedingly slender and
elongated. Posterior maxillipeds normal. Natatory legs with the rami compara-
tively less slender than in Dyspontius; outer ramus of Ist pair without any seta
inside the Ist joint, terminal joint well developed, with 3 spines outside and 3
setee inside. 4th pair of legs without any inner ramus. Last pair of legs
exhibiting a rudimentary structure similar to that in Dyspontius.

Remarks.—The above generic diagnosis chiefly refers to the species
described below, as I am by no means certain that the other 3 species
referred by Giesbrecht’ to this genus are in reality congeneric. The chief dif-
ferences from Dyspontius are found in the general form of the body, the struc-

ture of the siphon, and the armature of the outer ramus of the Ist pair of legs.

67. Cryptopontius brevifureatus, Giesbr.
(Plz XX):
Cryptopontius brevifurcatus, Giesbrecht, Asterocheride, p. 109, Pl. 1, fig. 7, Pl. 8, figs. 1—12.

Specific Characters.—Female. Body less expanded than in most other

Dyspontiide, with the anterior division oblong oval in outline, greatest width

only slightly exceeding half the length. Cephalic segment very large, nearly twice
as long as the remainder of the body, and narrowly rounded in front, with
no crista dorsally; rostral prominence very small. Epimeral lappets of the 2
succeeding segments rather broad and curved backwards; those of penultimate
segment extremely small and conical in form, being almost wholly concealed in
the dorsal view of the animal. Tail scarcely exceeding in length '/, of the
anterior division, genital segment much dilated in its anterior part. Caudal
rami very short, being scarcely longer than they are broad, and transversely
truncated at the end,’ outermost seta attached close to the apex and much
shorter than the innermost one; inner mediate seta twice as long as the outer,
and attaining about half the length of the body. Anterior antenne of moderate
length and composed of 9 joints, the elongate 2nd joint however exhibiting at
the base and at the end slight traces of a subdivision; terminal joint somewhat
longer than the 2 preceding ones combined. Posterior antennz with the last 9?
joints of about equal size; middle apical seta rather slender and flexuous. Siphon
extremely slender, extending almost to the end of the anterior division of the
body. Maxille with the outer lobe scarcely more than half as long as the
inner and having the 2 apical sete rather unequal in length; apical seta of inner
lobe very slender. Anterior maxillipeds with the dactylus much elongated and
narrow, secondary spine of moderate size and attached at a short distance from
the apical claw. Posterior maxillipeds with the hand densely ciliated outside.
Ist pair of legs considerably smaller than the 2 succeeding pairs, but having the
terminal joint of the outer ramus well developed; 2nd and 3rd pairs rather
strongly built, with the 2nd basal joint lamellarly produced inside; 4th pair with
the outer ramus smaller than that of the 2 preceding pairs, but otherwise of a
very similar structure, inner ramus wholly absent. Last pair of legs about as
in Dyspontius striatus.

Male, as usual, smaller than female, and having the anterior division
somewhat more depressed. Anterior antennee composed of only 10 joints, no
apical joint being cut off; 8th joint somewhat dilated and exhibiting near the
end in front a short dentiform projection.

Body in female of a whitish grey colour, with a faint yellow tinge.

Length of adult female 0.90 mm., of male 0.75 mm.

Remarks.—I1 cannot doubt that the above-described form is identical with
Giesbrecht’s species, though there are some few points of discrepancy. It is an
easily recognizable species, differing conspicuously from the other Dyspontide

in the general form of the body, especially as regards the female.

16 — Crustacea,

122

Occurrence.—The only place, where I have met with this form, is at
Korshavn, south coast of Norway. It occurred here occasionally on a sandy
bottom, at a depth of about 40 fathoms.

Distribution.—Bay of Naples (Giesbrecht).

Gen. 30. Aretopontius, G. O: Sars, n.

Generic Characters.—Anterior division of body greatly expanded, with
the cephalic segment exceedingly large and prominent at the postero-lateral cor-
ners; epimeral lappets of the 3 succeeding segments well developed and produced
laterally. Tail comparatively short, with the genital segment unusually broad,
being expanded on each side in a somewhat similar manner to that in the trunk-
segments. Anterior antenna comparatively short, 8-articulate (in female).
Posterior antenne very small, but of the usual structure. Siphon resembling in
structure that in Dyspontius, but less produced. Maxillee with the lobes rather
unequal in size. Both pairs of maxillipeds, but especially the anterior ones,
very strongly built. Ist pair of natatory legs with the terminal joint of the
outer ramus carrying inside 3 sete and outside only 2 spines; 4th pair with the
outer ramus normally developed, inner very small, biarticulate. Last pair of
legs still more rudimentary than in the 2 preceding genera.

Remarks.—This new genus differs from the 2 preceding ones in the very
broad and flattened form of the body, the comparatively short antenn, the very
powerfully developed maxillipeds, and, finally in the presence on the 4th pair of
legs of a distinct, though rather imperfectly developed inner ramus. It com-

prises as yet only a single species, to be described below.

68. Arctopontius expansus, G. O. Sars, n. sp.
Pl aX XI);

Specific Characters.— Female. Body very broad and pronouncedly depressed,
with the anterior division almost as broad as it is long. Cephalic segment occu-
pying more than half the total length, postero-lateral corners considerably pro-
jecting, free edges evenly curved, front narrowly rounded, without any dorsal
crest; rostrum of the usual short linguiform-shape. Epimeral lappets of the 3
succeeding segments rather produced; those of penultimate segment resembling

in shape the preceding ones, though somewhat smaller. Tail scarcely exceeding

in length 1/; of the anterior division; genital segment remarkably dilated in its
anterior part, forming on each side a large wing-like expansion somewhat similar
in shape to the epimeral lappets of the trunk-segments. Caudal rami short,
being scarcely longer than they are broad; outermost seta at some distance from the
apex and about the length of the innermost, the 2 median sete not much prolonged.
Anterior antenne not nearly attaining half the length of the cephalic segment,
and composed of only 8 joints, the 2nd much the longest, terminal joint scarcely
longer than the 2 preceding joints combined. Posterior antenne very small, with
the terminal joint somewhat longer than the penultimate one, middle apical seta
not much prolonged. Siphon rather coarse, extending about midway between
the insertion of the posterior maxillipeds and that of Ist pair of legs. Maxille
with the inner lobe almost twice as long as the outer and narrowly exserted
distally, apical seta comparatively short, those of the outer lobe subequal in length.
Anterior maxillipeds remarkably powerful, with the dactylus exceedingly strong
and hamiformly curved at the tip, secondary spine very small. Posterior maxil-
lipeds likewise rather strongly built, and having the terminal claw of the dactylus
densely clothed with small denticles. Ist pair of legs, as usual, somewhat smaller
than the 2 succeeding ones, which are rather strongly built, with the 2nd basal
joint triangularly produced inside. 4th pair of legs with the outer ramus normal,
inner ramus, however, very imperfectly developed, forming a small incurved stem
composed of only 2 subequal joints, each carrying a single short seta. Free
joint of last pair of leg extremely minute and apparently only provided with a
single small bristle

Colour not yet ascertained.

Length of adult female about 2 mm.

Male unknown.

Remarks.—This form may be readily recognised from the other members
of the present family by its very broad depressed body, and the greatly expanded
genital segment. Only the female sex is as yet known.

Occurrence.—Only 2 female specimens of this form have hitherto come
under my notice. They were taken, many years ago, at Hammerfest, western

Finmark, from a depth of about 20 fathoms.

124

Gen, 31. Bradypontius, Giesbr., 1895.

Syn: Artotrogus, Brady (part).

Generic Characters.—Anterior division of body more or less expanded,
with the cephalic segment large and considerably produced at the postero-lateral
corners; epimeral lappets of the trunk-segments well defined and successively
diminishing in size behind. ‘Tail somewhat more produced than in the 3 pre-
ceding genera, with the genital segment moderately dilated. Anterior antennz
more or less slender, and composed of a somewhat varying number of joints in the
different species. Posterior antenne of the usual structure. Siphon comparatively
slender, with the basal part somewhat thickened. Maxille with the lobes more
or less unequal. Maxillipeds comparatively slender. Natatory legs rather strongly
built; terminal joint of outer ramus in Ist pair with 3 spines outside and 3 sete
inside; 4th pair with the inner ramus distinctly 3-articulate, though in most cases
rather feebly developed, with some of the setw reduced. last pair of legs some-
what less rudimentary than in the preceding genera, the free joint being provided
with 3 bristles, 2 apical and one lateral.

Remarks.—The chief character by which this genus is distinguished, as
compared with the 3 preceding ones, is the presence on the 4th pair of legs of
a distinctly 3-articulate inner ramus, which however in most cases is rather feebly
developed. Otherwise it exhibits on the whole a rather close relationship to the
typical genus Dyspontius. 4 species referable to the present genus will be described
below, and a 5th species has been recorded by Giesbrecht from the Bay of Naples
under the name of B. siphonatus.

69. Bradypontius magniceps (Brady).
(Pl. LXXTI).
Artotrogus magniceps, Brady, Monograph of British Copepoda, Vol. III, p. 61, Pl. XCIIT, figs. 1—9.
Syn: Artotrogus orbicularis, Brady & Roberts. (not Boeck).
. > — Normanni, Canu (not Brady).
? Bradypontius Canwi, Giesbrecht.

Specific Characters.—Female. General form of body somewhat similar to
that in Dyspontius striatus, the anterior division being rather expanded, with the
greatest width almost equalling the length. Cephalic segment very large, occupying
about half the total length, and having the free edges evenly arched, postero-
lateral corners rather produced, frontal part rounded, without any dorsal crest.
Epimeral lappets of the 3 succeeding segments well defined and pointing obliquely

backwards; those of penultimate segment of same shape as the preceding ones, though

125i

somewhat smaller. ‘Tail ‘not attaining half the length of the anterior division;
genital segment moderately dilated in its anterior part; anal segment exceeding
in length the 2 preceding ones combined. Caudal rami rather produced, being
more than twice as long as they are broad, and fully attaining the length of the
anal segment; outermost seta not far from the apex and somewhat shorter than
the innermost; the 2 middle sete of moderate length. Anterior antenne about
half the length of the cephalic segment, and composed of 8 (or 9) joints, the 2nd
being much the largest; terminal joint almost the length of the 2 preceding ones
combined. Posterior antennz with the terminal joint longer than the penultimate
one, middle apical seta of moderate length, the other 2 very small. Siphon rather
slender, extending beyond the limits of the cephalic segment. Mandibles narrow
styliform, and distinctly denticulated at the apex. Mavxille with the lobes com-
paratively narrow and somewhat unequal in length, apical seta of the inner one
quite short, those of the outer slender and subequal. Maxillipeds well developed,
dactylus of the anterior ones moderately slender, with a small secondary spine
at some distance from the end; terminal claw comparatively short. 1st pair of
natatory legs not much smaller than the 2 succeeding ones, seta at the inner
corner of the Ist basal joint conspicuously thickened. 4th pair of legs with the
inner ramus much narrower than the outer and only slightly exceeding in length
the 2 first joints of this ramus combined, sete present in the usual number, but
rather reduced in size. Free joint of last pair of legs small, and as in the other
species provided with 3 bristles, the innermost one the longest. Ovisacs rather
large and globular in form.

Colour not yet ascertained.

Length of adult female 1.80 mm.

Male unknown.

Remarks.—I think I am right in identifying the above-described form with
Brady’s species, as it agrees fairly well in its outward appearance with the figure
given by that author. The apparent differences found in some of the structural
details may indeed be due to a less careful examination by the said author. It
appears to me somewhat more doubt‘ul, if the form described by Canu as Arto-
trogus Normani, and subsequently named by Giesbrecht Bradypontius Canui, is
in reality identical with the present species, as set forth by the last-named author
in his Monograph of the Asterocheridw; and the form briefly described and
figured by Giesbrecht in the same Monograph as B. magniceps, also seems to
differ in some respects.

The present species was at first erroneously identified by Brady and
Robertson with Artotrogus orbicularis Boeck; and though this mistake was sub-

126

sequently corrected, it was still referred by Brady in his Monograph to Boeck’s
genus, which in reality is so very different, that im my opinion it cannot even be
included in the present family.

Occurrence.— Only a few female specimens of this form have hitherto
come under my notice. They were taken free in the sea in two widely-distant
localities, viz., at Aalesund, west coast of Norway, and at Hammerfest, western
Finmark.

Distribution.— British Isles (Brady), ? coast of France (Canu).

70. Bradypontius papillatus (Scott).
(Pl. LXXIV).

Artotrogus papillatus, Scott, Sixth Annual Report of the Fishery Board for Scotland, Appendix,
p. 232, Pl. VII, figs. 7—12.
Syn: Bradypontius chelifer, Giesbr.

Specific Characters.—Female. Anterior division of body rather broad in
its posterior part, greatest width however not quite equalling the length. Cephalic _
segment very large, occupying more than half the total length, and gradually
contracted anteriorly, postero-lateral corners very prominent, frontal part nar-
rowly produced, with a very distinct crest running along its dorsal face; rostral
projection well marked, incurved. Epimeral lappets of the 2 succeeding segments
well developed and considerably divergent; those of penultimate segment, however,
rather small and conically pointed. Tail only slightly exceeding in length 1/; of
the anterior division; genital segment moderately dilated in front; anal segment
not attaining the length of the 2 preceding ones combined. Caudal rami about
twice as long as they are broad, and equal in length to the anal segment; outer-
most seta at some distance from the apex, and shorter than the innermost; the 2
middle sete of moderate size. Anterior antenne about half the length of the
cephalic segment, and composed of 9 joints, 2nd joint the largest, terminal joint
exceeding in length the 2 preceding joints combined. Posterior antenne resembling
in structure those in B. magniceps, except that the outermost apical seta is com-
paratively longer. Siphon scarcely extending beyond the insertion of the Ist pair
of legs. Maxillee with the lobes less slender than in B. magniccps, apical seta
of the inner one short, those of outer lobe very coarse, spiniform, and finely denti-
culated. Anterior maxillipeds with the dactylus rather strong and provided at
some distance from the end with 2 small thumb-like prominences, against which
the curved terminal claw may admit of being impinged; secondary spine very
small and placed outside the said prominences. Posterior maxillipeds normal.

Natatory legs resembling in structure those in B. magniceps, except that the inner

127

ramus in 4th pair is much smaller, scarcely attaining the length of the 2 first
joints of the outer one combined, and very narrow, with some of the sete aborted.
Last pair of legs about as in the preceding species.

Colour dark yellow or orange.

Length of adult female amounting to 1.60 mm,

Remarks.—I1 cannot doubt that the above-described form is that originally
recorded by Scott as Artotrogus papillatus, and that Giesbrecht’s Bradypontius
chelifer is the same species. It is true, that the number of joints in the anterior
antenne is indicated by both these authors to be only 8, and that the terminal
part of the dactylus in the anterior maxillipeds is represented much shorter and
thicker than in the specimen examined by me; but these apparent differences are

in all probability due to the circumstance that the specimens examined by those
authors had not arrived at full maturity, as proved by their much inferior size
(1.15—1.20 mm.) In all other respects the agreement seems to be perfect.
From the type species, B. magniceps, the present one is easily distinguished by the
rather different form of the cephalic segment and of the epimeral lappets, as also by
the comparatively shorter caudal rami. The very feeble development of the inner
ramus on the 4th pair of legs forms another rather characteristic specific mark.

Occurrence.—Some few female specimens of this form were collected, many
years ago, in 2 localities on the west coast of Norway, viz., at Aalesund and
Eggesbones. The specimens were taken free in the sea, at depths ranging from
20 to 40 fathoms.

Distribution.—British Isles (Scott), Bay of Naples (Giesbrecht).

71. Bradypontius major, G. O. Sars, n. sp.
(PL. LXXV).

Specific Characters:— Female. General form of body somewhat similar to
that in B. papillatus, the cephalic segment being very large and gradually con-
tracted anteriorly, with a well-marked dorsal crest running along its frontal part.
Epimeral lappets of the 3 succeeding segments more closely crowded together and
less unequal than in the said species; those of penultimate segment well developed,
though somewhat narrower than the others. Tail comparatively short, only slightly
exceeding in length '/; of the anterior division; genital segment considerably
dilated in its anterior part; anal segment equalling in length the 2 preceding
ones combined. Caudal rami scarcely twice as long as they are broad, and shorter
than the anal segment, apical sete about as in the preceding species. Anterior

antenne not very elongated, but composed (in the specimen examined) of no less

128
than 13 well-defined joints, a short joint being divided off from the elongated 2nd
joint both at the base and at the end, and moreover each of the 2 joints pre-
ceding the terminal one being distinctly subdivided; terminal joint about the
length of these 4 joints combined. Posterior antenne a little more slender
than in B. papillatus, but otherwise of a very similar structure. Siphon rather
produced, extending considerably beyond the limits of the cephalic segment.
Mandibles very slender and distinctly denticulated at the tip. Maxille with the
lobes narrow and rather unequal in length; apical seta of the inner one much
produced, those of the outer rather slender. Anterior maxillipeds with the dactylus
much more slender than in B. papillatus, with only a single small thumb-like
process rather far from the apex, secondary spine well marked. Natatory legs
with the rami comparatively less slender than in that species; inner ramus of
4th pair more fully developed, exceeding in length the first 2 joints of the outer
one combined. Free joint of last pair of legs a little larger than in B. papillatus.

Male considerably smaller than female, and having the anterior division
less expanded. Anterior antenne, as in female, composed of 13 joints, 6th and
7th joints very short and less sharply defined, 10th joint conspicuously dilated
and armed anteriorly with 2 slender spines, movable terminal part distinctly
biarticulate. Inner ramus of 4th pair of legs comparatively longer than in female,
terminal joint produced at the outer distal corner to an outward-curving denti-
form projection, outer apical seta, as also that of the outer edge replaced by a
short club-like spine.

Body in female of a dark yellowish grey colour, and ornamented on the
dorsal face with a reddish branching pigment.

Length of adult female amounting to 2.40 mm., of male to 1.95 nm.

Remarks.—This form is closely allied to B. papillatus, but of much larger
size, and moreover differs conspicuously in the shape of the epimeral lappets of
the trunk-segments, as also in some of the structural details, as indicated in the
above diagnosis.

Occurrence.—Solitary specimens of this large species have been taken
at Aalesund, west coast of Norway, and in the Trondhjem Fjord, at Rodbjerget,

in both localities from considerable depths.

72. Bradypontius caudatus, G. O. Sars, n. sp.
(Pl. LXXVJ).

Specific Characters.—Female. Body comparatively more slender than im

the other species, with the anterior division moderately expanded. Cephalic

129

segment large, though scarcely occupying half the total length, and only slightly
contracted anteriorly, frontal crest only faintly indicated, postero-lateral corners
of the segment fairly prominent. Epimeral lappets of the 3 succeeding seg-
ments moderately produced; those of penultimate segment rather smaller than
the preceding ones. ,Tail comparatively more produced than in the other species,
attaining nearly half the length of the anterior division; genital segment not
much expanded in its anterior part; anal segment scarcely as long as the 2
preceding ones combined. Caudal rami about twice as long as they are broad,
and slightly dilated in the middle; outermost seta rather far from the apex and
much shorter than the innermost, the 2 middle sete of moderate length. Anterior
antennse unusually slender and elongated, considerably exceeding half the length
of the cephalic segment, and composed of 12 well-defined joints, the last of
which is the longest. Posterior antenne likewise rather slender, with the ter-
minal joint nearly twice as long as the penultimate one. Siphon moderately
produced, extending about to the insertion of the Ist pair of legs. Maxillee with
the lobes not very unequal; apical seta of the inner one quite short, those of
the outer very coarse, spiniform and densely spinulose. Maxillipeds resembling
in structure those in B. major, the dactylus of the anterior ones being very
slender, with only a single small thumb-like process at some distance from the
end, terminal claw much curved, secondary spine small. Natatory legs rather
strongly built, with the exterior edge of the outer ramus coarsely serrate; inner
ramus of 4th pair not much shorter than the outer, but rather narrower. Free
joint of last pair of legs somewhat more produced than in the other species.

Colour reddish brown.

Length of adult female reaching to 2.90 mm.

Male unknown.!)

Remarks.—This form grows to a still larger size than B. major, and is
indeed the largest of all the siphonostomous Cyclopoida with which I am acquainted.
It moreover exhibits several well-marked differences from the other species, both
as to its outward appearance and the structural details. The specific name
alludes to the unusually produced tail.

Occurrence.—2 female specimens only of this form have come under my
notice. They were taken, many years ago, at Tjoto on the Nordland coast, from

the considerable depth of 150 fathoms

1) It may be, however, that the male specimen mentioned above as belonging to 6. major,
should more properly be referred to the present species, though it was found in company with
the former. Indeed, on a closer examination, I have found that the caudal rami in that specimen,
as also the mutual relations of the joints in the inner ramus of the 4th pair of legs, agree better
with the present species.

17 — Crustacea.

Gen. 32. Cribropontius, Giesbr. 1899.
Syn: Artotrogus, Brady (part).

Generic Characters.—Body robust, with strongly chitinised integuments,
and with some of the epimeral lappets very prominent. Tail somewhat pro-
duced and having the genital segment in female less expanded than in the other
genera. Caudal rami lamellar, with comparatively short apical sete. Anterior
antenne comparatively stout and scarcely at all attenuated distally. Posterior
antenn with the terminal joint comparatively short. Siphon rather strong and
not much produced. Maxille with the lobes very unequal in size and each
provided with 2 slender apical sete. Both pairs of maxillipeds, but especially
the posterior ones, very powerfully developed. Natatory legs on the whole agreeing
in structure with those in Bradypontius; inner ramus of 4th pair, as in that
genus, distinctly 3-articulate. Last pair of legs somewhat more fully developed
than in the other Dyspontide.

Remarks.—This genus, established by Giesbrecht, is allied to Brady-
pontius, agreeing with it in the presence of a distinctly 3-articulate inner ramus
on the 4th pair of legs. It differs however in some points rather conspicuously,
both as regards the outward appearance and some of the structural details, and
therefore ought evidently to be supported. We do not know at present more
than a single species, to be described below.

73. Cribropontius Normani, (Brady).
(Pl. LXXVII).
Artotrogus Normani, Brady, Monograph of British Copepoda, Vol. II, p. 63, Pl XCI, figs. 12—15,
Pl XC ne! 14 Pi XC gst:
Syn: Dyspontius Normani, Brady & Roberts.
Bradypontius Normani, Giesbrecht.

Specific Characters.—Female. Anterior division of body moderately
expanded and somewhat depressed, with the greatest width slightly exceeding */;
of the length. Cephalic segment large, though not occupying quite half the total
length, free edge evenly curved, frontal part rounded, without any dorsal crest,
postero-lateral corners divided into 2 short lappets; rostral projection well defined,
incurved, Epimeral lappets of the 3 succeeding segments rather unequal, those
of antepenultimate trunk-segment much the largest, and greatly projecting to each
side; those of penultimate segment well developed, though smaller than the 2
preceding pairs. ‘Tail- attaining nearly half the length of the anterior division;

genital segment gradually somewhat dilated anteriorly; anal segment about the

131

length of the 2 preceding ones combined, and conspicuously widening distally.
Caudal rami rather broad, and somewhat shorter than the anal segment, with
the inner edge finely ciliated, outer edge exhibiting, at some distance from the
end, a distinct ledge, to which the outermost seta and the very small accom-
panying dorsal bristle are attached; apical setee comparatively short, but rather
coarse and densely ciliated. Anterior antenne not nearly attaining half the length
of the cephalic segment, and composed of 9 joints rather densely clothed with
short, but rather coarse, curved sete, 3rd joint much the largest, terminal joint
club-shaped and about the length of the 2 preceding joints combined. Posterior
antenne with the terminal joint shorter than the penultimate one, apical sete
spiniform, the middle one, as usual, the longest. Siphon extending about midway
between the insertion of the posterior maxillipeds and that of 1st pair of legs.
Mandibles minutely denticulated at the apex. Maxille with the outer lobe scarcely
half as long as the inner, apical setee on both lobes very slender and curved.
Anterior maxillipeds with the dactylus very strong and evenly curved in its distal
part, terminating in a blunt point; secondary spine of moderate size. Posterior
maxillipeds still more powerful than the anterior ones, with the dactylus exceedingly
strongly built, its proximal joints being unusually stout, with the spines issuing
inside very coarse, terminal claw occupying rather more than half the length of
the dactylus. Natatory legs well developed, with the rami comparatively broad;
inner ramus of 4th pair, however, considerably narrower than the outer and also
somewhat shorter. Free joint of last pair of legs slightly produced, oblong
quadrangular in form, and carrying at the tip one long and 2 short bristles.
Ovisacs of. moderate size and globular in shape.

- Body of a light yellowish grey colour and ornamented with a number
of very conspicuous brick-red patches, 2 median, the one occupying the front
part of the cephalic segment, the other the dorsal face of the 3 succeeding
segments, and 3 lateral on each side, the 2 anterior pairs occurring on the
cephalic segment, the posterior pair on the projecting epimeral lappets of the
3rd segment; ova in the ovisacs of a yellowish red colour.

Length of adult female amounting to 1.70 mm

Remarks.—This form was at first recorded by Brady and Robertson as
a species ‘of the genus Dyspontius, and was subsequently by the first-named
author erroneously referred to the genus Artotrogus of Boeck. This mistake was
corrected by Giesbrecht, who found it to agree much better with the genus
Bradypontius, to which it was indeed at first referred by that author. After
having examined more closely a specimen sent to him by Scott, he felt how-

ever justified in excluding it also from this genus as the type of a new nearly-

Nees

allied genus. The present form is indeed, easily distinguishable from any of the
species of that genus, and is, moreover, in the living state at once recognised
by its peculiar colour, which has also been mentioned by Scott.
Occurrence.—I have met with this handsome form occasionally in 2 or
3 places on the west coast of Norway in depths ranging from 20 to 50 fathoms.
Distribution.—British Isles (Brady), Madeira (Thompson).

Fam. 8. Artotrogide.

Characters.—Body very broad, more or less clypeiform, with the 2
posterior trunk-segments imperfectly developed. Tail quite short, and composed
in female of 4, in male of 5 segments. Antenne and oral parts on the whole
built on the same type as in the Dyspontiide. Only 3 pairs of natatory legs
present, the 4th pair being wholly absent Last pair of legs not defined from
the corresponding segment. Ovisacs in female more or less concealed beneath
the body.

Remarks.—This family, as here defined, does not answer at all to the
family Artotrogide of Brady, which, like the family Asterocheridw of Giesbrecht,
was established to include all the siphonostomous Cyclopoida. In the restriction
here adopted, this family only comprises 2 genera, viz., Artotrogus Boeck and
Dystrogus Giesbrecht, both of which agree in one very essential character, viz.,
in the total absence of the 4th pair of legs, in this respect exhibiting an approach
to the next family, the Cancerillide. The exact comparison of these 2 genera
is rendered somewhat difficult by the circumstance that of the one (Artotrogus)
we only know the female sex, of the other (Dystrogus) only the male sex. It

is evident, however, that they represent two distinct generic types.

Gen. 33. Artotrogus, Boeck, 1859.

Generic Characters.—Body greatly expanded, rounded in form, with the
epimeral lappets of the cephalic segment and the 2 anterior trunk-segments well
developed, imbricate. The last 2 trunk-segments almost wholly concealed, with

no epimeral lappets. Tail very short, projecting only slightly beyond the anterior

division; genital segment (in female) with a lamellar, posteriorly-pointing expansion
on each side. Caudal rami short. Anterior antenne comparatively small and
resembling in structure those in the Dyspontiide. Posterior antenne still smaller,
4-articulate, with the outer ramus rudimentary. Siphon well developed and rather
coarse, gradually tapered distally. Mandibles without any palp. Maxille with
the lobes rather unequal in size. Both pairs of maxillipeds powerfully developed.
Natatory legs strongly incurved, with the rami subequal in length, and on the
whole built on the same type as in the Dyspontiide, except that the 4th pair
is wholly wanting.

Remarks.—This genus was established as early as the year 1859 by
Boeck, to include a peculiar Copepod found by him on the south coast of Norway.
As only a solitary specimen was observed by that author, the generic characters
were not made out satisfactorily, and several errors were indeed introduced,
which however have partly been corrected by subsequent authors. The genus

comprises as yet only a single species, to be described below.

74. Artotrogus orbicularis, Boeck.
(Pl. LXXVIID.
Artotrogus orbicularis, Boeck, Tyende nye parasitiske Krebsdyr; Chr. Vid. Selsk. Forhandl. f. 1859,
De ile Plier see 1.0;

Specific Characters.— Female. Body pronouncedly clypeiform, and nearly
orbicular in outline, with the dorsal face evenly vaulted, the ventral flattened or
concaved. Cephalic segment very large, occupying rather more than half the
total length, and having the free edges evenly arched; postero-lateral corners
triangularly produced and curved backwards; frontal part scarcely prominent and
without any dorsal crest; rostral prominence imperfectly defined and blunted at
the end. Epimeral lappets of the 2 succeeding segments large and recurved.
Tail extremely short, being almost wholly received within the deep emargination
formed behind between the epimeral lappets of the 2nd free trunk-segment;
genital segment sub-quadrate in form, and produced on each side behind to a
narrow lamella flanking the 2 succeeding very short segments; anal segment
larger than those segments combined and somewhat widening distally. Caudal
rami scarcely longer than they are broad, and rather wide apart, outermost
seta at some distance from the end and about the length of the innermost; the
2 middle setee not much produced. Anterior antenne scarcely attaining in length
/; of the cephalic segment, and composed of 9 joints clothed with moderately
long sete, Ist and 3rd joints the longest; terminal joint club-shaped and about

the length of the 2 preceding ones combined; the esthetask, attached to this

joint, at some distance from the end, of moderate length. Posterior antenns
with the outer ramus very small and provided with only a single minute
bristle; terminal joint longer than the penultimate one and somewhat curved in
its outer part, seta of outer edge attached at a short distance from the end.
Siphon extending only slightly beyond the insertion of the posterior maxillipeds,
Maxille with the outer lobe scarcely half as long as the inner; apical sete of
both lobes rather slender. Anterior maxillipeds with the dactylus exceedingly
strong and hamiformly curved at the end; secondary spine small. Posterior
maxillipeds more normally developed, terminal claw of the dactylus occupying
about half its length, and finely denticulate inside. Ist pair of natatory legs
somewhat smaller than the 2 succeeding ones, and having the terminal joint of
outer ramus of moderate size and provided outside with 3 spines and inside
with 3 sete. Inner ramus of 3rd pair differing from that of 2nd pair in the
absence of the usual apical spine. Not even the slightest rudiment of a 4th par
present. Last pair of legs only represented by 3 small bristles, all issuing
immediately from the sides of the corresponding segment. Lateral cceca of
intestine very fully developed, extending along the sides of the cephalic segment
and also penetrating into the adjacent part of the trunk, being divided outside
into numerous narrow lobules. Ovisacs globular in form and wholly concealed
beneath the posterior part of the trunk.

Body of a light yellowish brown colour, with the intestine and its lateral
ceeca of a darker hue; ova in the ovisacs orange-coloured.

Length of adult female about 2 mm.

Male (at least in its adult state) unknown.')

Remarks.—The present Copepod cannot be confounded with any of the
other siphonostomous Cyclopoida, being clearly distinguished by the pronouncedly
clypeiform shape of the body and its nearly circular form. It is however not
improbable that the hitherto unknown female of Dystrogus will be found to
approach nearer to Artotvogus in the general form of the body than does the male.

Occurrence.—This peculiar form was observed by my late father at
a very early period, at Manger, north of Bergen, where several specimens were
taken by him from nudibranchiate Mollusca. The specimen described by Boeck
was found by him on a species of Doris taken at Farsund, south coast of Norway.
I have myself met with this form in two widely distant localities of the Norwegian

coast, viz., at Kleven, near Mandal, and at Hasvig, western Finmark. In both

1) It is very questionable if the specimen described by Scott as the male of the present
form was in reality of that sex, and I think that Giesbrecht was right in believing it to be
quite an immature form, in which the sexual characters had not yet appeared.

localities the specimens were taken in the free state among alge and other

marine growths.
Distribution.—British Isles (Scott), Kara Sea (Hansen), Ceylon (A. Scott).

Fam. 9. Cancerillide.

Characters.—Body of rather different shape in the different genera, but
scarcely clypeiform. The 2 or 3 posterior trunk-segments imperfectly developed,
without any epimeral plates. Tail short or moderately produced, with a some-
what varying number of segments. Anterior antenne normal. Posterior antenne,
however, very unlike those in the preceding families, being transformed into strong
prehensile organs terminating in a powerful curved claw. Siphon imperfectly
developed, in some cases obsolete. Mandibles short, mucroniform, extending
straight inwards, palp absent. Maxillee likewise incurved and terminating in one
or 2 setiferous lobes. Maxillipeds on the whole built in the usual manner;
though attached at a somewhat greater distance from the median line than in the
other families. Some of the posterior pairs of legs imperfectly developed or quite
wanting, this imperfect development in some cases even extending to all the
legs (in female).

Remarks.—This family answers to the subfamily Cancerilline of Giesbrecht,
and contains as yet only 2 genera, to be treated of below. These genera, it is
true, differ considerably, both as to the outward appearance of the body and to
some of the structural details, but yet exhibit some well-marked features in
common, the most essential of which are the prehensile character of the posterior

antenne, and the imperfect development of the siphon and of some of the legs.

Gen. 34. Parartotrogus, Scott, 1893.

Generic Characters.—General form of body not deviating much from the
usual type, the anterior division being moderately dilated and somewhat flattened.
Cephalic segment more or less expanded in the middle, with the frontal part
somewhat produced, but without any true rostrum; postero-lateral corners not

produced. The 2 succeeding segments well developed, with rounded epimeral

136

plates; the 2 posterior trunk-segments, however, very small and not produced
at all laterally. Tail normally developed, and composed in female of 4, in male
of 5 segments. Caudal rami comparatively small. Anterior antenne resembling
in structure those in Artotrogus, though somewhat coarser; those in male (according
to Scott) distinctly hinged, but without supplementary esthetasks. Posterior
antennee very powerfully developed and strongly clawed at the end, outer ramus
present as a delicate setiferous lamella. Siphon obsolete, the 2 lips being scarcely
at all produced. Mandibles terminating in a simple point. Maxille with 2 very
unequal lobes. Maxillipeds comparatively slender, and of quite normal structure.
Only 3 pairs of natatory legs present, Ist pair with both rami only composed
of 2 joints. 4th pair of legs wanting, or only present as a very slight rudiment.
Last pair of legs represented by a small bisetose joint accompanied outside by
the usual bristle.

Remarks.—This genus was established in the year 1893 by Scott, to
include a peculiar Copepod, P. Richardi, found by him on the Scottish coast;
and subsequently also observed by Giesbrecht. The generic name proposed by
Scott is somewhat inappropriate, as the affinity of this genus to Artotrogus is a
very remote one. The genus comprises as yet 2 nearly-allied species, one of

which will be described below.

75. Parartotrogus arcticus, Scott.
(PIS 1.x Ka):
Parartotrogus Richardi, vay. arctica, Scott, On some Entomostraca collected in the Arctic Seas;
Ann. Mag. Nat. Hist., Ser. 7, Vol. VILL, p. 352, Pl. VI.

Specific Characters.— Female. Body comparatively more slender than in
the type species, with the anterior division less dilated, and oval in outline.
Cephalic segment very large, occupying about half the total length, but not nearly
so much expanded in the middle as in P. Richard, the lateral edges being
evenly arcuate; frontal part conspicuously exserted and broadly truncated at the
end. Epimeral plates of the 2 succeeding segments well defined and rounded at
the end. The last 2 trunk-segments abruptly much narrower and subequal in
size. ail about equalling in length half the anterior division; genital segment
fully as long as the 3 succeeding segments combined, and gradually widening
anteriorly, forming on each side in front a somewhat projecting angle; anal
segment longer than the preceding one. Caudal rami somewhat longer than they
are broad and rather far apart, apical setee comparatively short, the inner mediate
one scarcely exceeding half the length of the tail. Anterior antenne not quite

attaining half the length of the cephalic segment, and somewhat bent at the base,

Phas

being composed of 9 joints rather densely clothed with short curved sete; 2nd
joint the largest and rather broad at the base; terminal joint nearly as long as
the 2 preceding ones combined, and carrying at some distance from the end the
usual cesthetask. Posterior antenne exceedingly powerful and exhibiting a some-
what sigmoid curvature, penultimate joint much the largest, terminal joint short
and thick, carrying on the end a very strong curved claw accompanied inside
by another much smaller claw; outer ramus forming a narrow, lancet-shaped
lamella attached near the end of the 2nd (basal) joint, and provided with 3
small bristles. Mandibles comparatively short, and terminating in a simple point.
Maxille with the outer lobe very small and provided at the tip with 3 com-
paratively short subequal sete; inner lobe widening considerably distally, spatu-
late in form, and carrying on the transversely truncated extremity 3 ciliated
spines and 2 abruptly recurved slender and densely ciliated sete. Anterior
maxillipeds with the dactylus rather slender, biarticulate, and provided beyond
the middle with a small secondary spine, tip sharply pointed. Posterior max-
illipeds with the hand somewhat fusiform, and provided at about the middle of
the inner edge with a ciliated seta; dactylus slender, triarticulate, with no spine
inside the 1st joint, terminal claw occupying about half the length of the dactylus.
Ist pair of legs with no seta inside the proximal joint of the outer ramus, distal
joint of this ramus with 3 very slender spines outside; distal joint of inner ramus
rather large, with 7 sete, one of which issues from the outer edge. The 2 suc-
ceeding pairs of legs with both rami distinctly 3-articulate and rather slender,
spines of outer ramus dagger-shaped; inner ramus with the terminal joint produced
at the end into 2 dentiform projections, between which in the 2nd pair 2 sub-
equal sete are affixed, in the 3rd pair only a single dagger-like spine; number
of sete on the inner ramus of the latter pair somewhat reduced, the middle
joint having only a single seta and the terminal joint 2 sete inside. 4th pair
of legs present as a small bisetose joint attached to each side of the corresponding
segment and accompanied outside by a small bristle. Free joint of last pair of
legs of somewhat larger size and provided with 3 sete, 2 apical and one lateral.

Male (according to Scott) very like the female in its outward appearance,
but of smaller size.

Colour in female pale yellow, with darker translucent ovarial tubes and
with some slight ochraceous pigmentary patches on each side of the cephalic
segment and trunk; eye bright red and occurring unusually far back.

Length of adult female 0.80 mm.

Remarks.—This form is closely allied to the type species, P. Richardi

Scott, and was indeed regarded by that author as merely a variety of this species.
18 — Crustacea,

138

It ought, evidently however, in my opinion to be considered as specifically distinct,
as it differs conspicuously not only in the more slender form of the body and
the far less expanded cephalic segment, but also in some of the structural details.
Thus the inner ramus of the 3rd pair of legs is distinctly 3-articulate, whereas
in the type species it is composed of only 2 joints; and the 4th pair of legs,
which in P. Richardi is wholly absent, is represented by a well-marked, though
very small rudiment. Finally, the distal joint of the inner ramus in the Ist pair
of legs has 2 sete more than in P. Richardi.

Occurrence.—Two or three female specimens of this form were collected,
many years ago, at Kvalg, on the Nordland coast, from a depth of 40 —50 fathoms.

Distribution.—Arctic Sea, off Spitsbergen and Novaja Zemlia (Scott).

Gen. 35. Cancerilla, Dalyell, 1851.

Syn: Caligidiwn, Claus (male).

Generic Characters.—Form of body very dissimilar in the two sexes,
being exceedingly short and stout in female, in male much more slender.
Cephalic segment in female greatly inflated, in male sub-depressed; rostral pro-
jection in both sexes obsolete. The succeeding segment well marked, with the
epimeral parts less distinctly defined in female than in male; the 3 remaining
trunk-segments in both sexes imperfectly developed, without any epimeral plates.
Tail in female very short and composed of only 3 segments, in male more pro-
duced and 5 articulate. Caudal rami smaller in female than in male. Anterior
antenne in female comparatively short, with the number of joints considerably
reduced; those in male not at all hinged, but of larger size and composed of a
greater number of joints, being moreover provided with numerous recurved sensory
filaments. Posterior antenne in both sexes distinctly prehensile, terminating in
a strong claw, outer ramus absent. Siphon faintly indicated by a slight pro-
longation of the lips, and turned anteriorly. Mandibles with the extremity slightly
dilated and indistinctly denticulated. Maxille with only a single lobe turned
inwards. Both pairs of maxillipeds short and stout, especially in female. 4th
pair of legs absent in both sexes. All the remaining legs in female reduced, and
unfit for swimming; the 2 anterior pairs in male natatory, Ist pair smaller and
less perfectly developed than 2nd, which are quite normal, with both rami

3-articulate. Last pair of legs in both sexes small, untarticulate,

Remarks.—This genus was established as early as the year 1851 by the
English naturalist Dalyell, to include a peculiar parasite found by him on a species
of brittle-stars. The systematic position of the genus has long remained very
uncertain; but Giesbrecht clearly pointed out its near relationship to the siphono-
stomous Cyclopoide (Asterocheride) and particularly to the genus Purartotrogus
of Scott. I also fully agree with Giesbrecht, that the genus Caligidium of Claus
ought to be regarded as a synonym, being founded on adult males belonging

to this genus.

76. Cancerilla tubulata, Dalyell.
(Pl. LXXX).
Cancerilla tubulata, Dalyell, The powers of the Creator, Vol. 1, p. 233, Pl. LX, figs. 1—5.

Syn: Caligidium vagabundum, Claus. (adult male).

Specific Characters.—Female. Body very short and stout, almost cordi-
form in shape, with the anterior division greatly inflated, transversely ellipsoid
in outline, the width considerably exceeding the length. Cephalic segment occu-
pying by far the greater part of the body, free edges strongly curved and minutely
hairy in their anterior part, front very slightly produced. The succeeding segment
with the epimeral parts less distinctly defined, forming part of the hind boundary
of the anterior division; the remaining trunk-segments imperfectly developed and
only visible as narrow stripes. Tail very short, with the genital segment
exceedingly dilated, being nearly 3 times as broad as it is long, and projecting
behind on each side in an angular corner; anal segment larger than the pre-
ceding segment, and somewhat contracted distally. Caudal rami comparatively
small and rather far apart, apical sete short, the inner mediate one being, as
usual, the longest. Anterior antenne comparatively small and composed of only
6 joints clothed with short curved sete; 1st joint much the largest and rather
broad; terminal joint about the length of the 2 preceding ones combined, and
carrying near the end a comparatively small wsthetask in addition to the sete.
Posterior antenne very strong and highly chitinized; 1st joint rather short, the
2 succeeding ones of about equal size, terminal joint somewhat shorter, but con-
spicuously widening distally, apical claw exceedingly. strong and curved. Maxillie
with the terminal lobe oblong in form and provided with 3 spreading non-ciliated
setee of moderate length and accompanied by a small bristle. Both pairs of
maxillipeds short and stout, with the dactyli not much produced, but rather
coarse. Ist pair of legs consisting each of @ thickish basal part carrying outside
a small bristle, and 2 uniarticulate rami, the outer one lamelliform and edged

with 6 comparatively short simple sete, one inside, 2 at the tip, and 3 outside;

140

inner ramus very small, cylindric in form, and carrying 2 minute sete on the
tip. 2nd pair of legs much smaller than the Ist and farther from the
median line, basal part less perfectly defined, though carrying outside the usual
bristle; outer ramus represented by a narrow oblong joint edged outside with
6 very minute and somewhat unequal bristles; inner ramus reduced to a minute
conical process. 3rd pair of legs extremely small and rudimentary, being only
represented by a minute bisetose joint, without any accompanying bristle outside.
5th pair of legs likewise uniarticulate, but slightly larger than 3rd, and accom-
panied outside by the usual bristle. Ovisacs globular, projecting on each side,
and rather large, in Some cases almost attaining the size of the whole body.
Male very unlike the female in its outward appearance, and of much
more slender form of body. Cephalic segment occupying about half the total
length, and oval in outline, being scarcely as broad as it is long, lateral edges
evenly cuved, frontal part obtusely truncated. 2nd segment normally developed,
with the epimeral plates well defined and triangnlarly pointed behind. The 3
succeeding trunk-segments very small and narrow, not being at all expanded
laterally. Tail nearly half as long as the anterior division and composed of 5
well-defined segments, the Ist of which (the genital segment) is much the largest
and almost quadrate in outline, containing, as a rule, on each side a rounded
spermatophore; anal segment somewhat larger than the preceding one. Caudal
rami considerably more produced than in female, being more than twice as long
as they are broad, and slightly tapered distally; inner mediate seta very long,
attaining almost half the length of the body; the other sete comparatively
short. Anterior antenne much larger than in the female and composed of 10 well
defined joints, being not at all hinged, but provided with numerous delicate
sensory filaments curving backwards and especially densely crowded on the 1st
very large joint. Posterior antenne of exactly the same structure as in the female,
though somewhat less strong. Oral parts likewise very similar, except that the
maxillipeds are a little less robust. Legs, however, rather dissimilar, the 2
anterior pairs being much more fully developed and adapted for swimming. Ist
pair of legs with the basal part of normal appearance, and distinctly biarticulate ;
outer ramus resembling in shape and armature that in female, but comparatively
larger and having the marginal sete distinctly ciliated; inner ramus distinctly
biarticulate and nearly as long as the outer, proximal joint small, with a single
seta inside, distal joint oblong oval, and edged with 5 ciliated sete. 2nd pair
of legs quite normally developed, with both rami 3-articulate and armed in the
usual manner with spines and sete. 3rd pair of legs exhibiting exactly the same

rudimentary condition as in the female. Last pair of legs with the free joint

Copepoda

Pl LXV:

Cyclopoida.

Ascomyzontide.

WWW

{
ly

\
4

SSS. \
Sa a
mar i
‘

es: oe a iniine 2

oe ae
gt
7

UN pais ve\\\ cael

Zw ore SN
as he Sm ou
f
y ‘J
ee:

Leptomyzon elegans, (A. Scott).

Ge Oe Sars; del:

See he ti Oe AU: a ek es
or Fei een 1 eta ae = Aun’ Me
, ear Are Sa OL ee a
WS eas. 'g RRL
a ne ele ae eG
oat Pe ; de cot ek -
> a -
a a. yO Roe « ei ee ae
, ~~ ae if “AR : J :
BAe relly went a ss Pe
Rieter ves» ~ Ee 2 2% -
ee bee | ea
\, Ae ee at s
‘AS eee, 0-2 Le oy ea me p a5 pe
(a ik ae oa vate
ary, Miner sent hod oe coe tae
, - & ae eh C . a aT ac T -
mo ta? a 7 7 “7h. P|
4 rae) eee
oO eae => « = - Jiibern es :
7m on v4: s a we edhe | => a oe
ie eS). =. ae
tae ae Jes *
ah (be —— a ion A _ 7

: a
© Teens
iy aff

‘ ™
a =

a

Copepoda

PRE Vilc

Cyclopoida.

Ascomyzontide.

GenOn sats Gel:

Scottocheres elongatus, Scott.

at

Copepoda

Acontiophoridz. Cyclopoida. Pl. LXVIL

NGOs Sars del:
Acontiophorus scutatus, Brady.

Copepoda

Myzopontiide. Cyclopoida. Ply BXVvir

G. O. Sars, del.

Myzopontius pungens, Gsbr.

Copepoda

Myzopontiide. Cyclopoida. Pile Exe

G. O. Sars, del.

Neopontius angularis, Scott.

Ls

its :

7 » 7
" ‘@ _ a
Tay en aE ee
Fo tees
~~ vo. ne q Vs. ee
“i Mureaiees +7
~ " _ a
¢) ui wah Je
¢ ‘ 7 ant

as +. ;
Z ve ; an = A > —_,” it ‘ mF :
—e'; 2 Sar 8 ee ae en Ean ae a : “oe —“y
| eee ia he a [hea laden aed Bhan TE cdo h 7 : ria
= : ae > ie a ae ie we Oe _ _, t . by }
as ts y pie | roe AY ee) ery eo Ns - Pav we : 2
cy > we 4 1 s ide OG, Ae ot) te he aete NY La aay.
m ES ite OU hy Sa = Ee aN Te
: 7 > : 7 yt ft thats : nae nih > ee © a a aon
# - : - roe es tas) > Pe a Tae a ae = Poe ¥ 7 Pe ; :
ee -—) i 7 7, =) i - am a ees Rees ie as : sg ae : ad - >"
‘ ee : ' ; ;

4 ASpucl P i .
aa ce . a ~ i = mS
a . : - © == 1,8
: = P al -,
¥ —s iy T 7 /
- 7 : ’ a 7 + " a >
: ec. - ' Oa oe ae tl Si
a ae | rae n gy ee
4 s af a 7 ot Te) >
_ = h.. oe 2 _ :
aa oe . - ~ os =P cir = 40° es: ,
_- = 58 = 7 Od ae ee * a ee —.
ook, «gt Se ag ed plans oat
4 ae ye ALL >
}: m= ae ; f -
7 7 - a <i ~~ ae -
= i ho ® ay i oP : - ' —, '
: ~y - : : 7
nae Sis ita | :
¥ ~
: ¥ ay ed ie
as - -

Copepoda

Dyspontiide. Cyclopoida. Pl. LXX.

GaOy sats adel:
Dyspontius striatus, Thorell.

e<-¢

ee ae ee |)

Copepoda

Dyspontiidze Cyclopoida. Pl. LXXI.

G: ©; Sars; del:

Cryptopontius brevifureatus, Gsbr.

Copepoda

Dyspontiide. Cyclopoida. Pl. Lexi.

Ge OF Satss del:
Arctopontius expansus, G. O. Sars.

ae
oP a
_
a
-

yy

Copepoda

Pl]. LXXIII.

Cyclopoida.

Dyspontiidz.

G. ©. Sars, del.

Bradypontius magniceps (Brady).

Copepoda

Ply Lxxaiy.

Cyclopoida.

Dyspontide.

A > .
PX et
Lxxr“ee i ‘
f
1 ARS

IN

sy Sh hew
Ly Vp
LWIYGLZ
VA -

. Ut Wh Ya z

LZ
EBLE L
Git AE
a
aS

G. O. Sars, del.

Bradypontius papillatus (Scott).

. ~
t
na
a
7 oa =e 7
‘ > i .
- 1
=) - :
a = 5
a | ae ©
7 -
} ‘’
. F
= San . , «
. 2
— -
ie
ad
a i
3
} =
»
=i
P. i
Th i
a : ' -
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7
= ‘|
Av¢ , a
*
r a i si
; F
i
: ta
a is
. heme
. = : 7
¢ 2 7 -
- ie _ r a ~~
t= 7 ot
iw
Yo
* : P =
7 >
i y
i
= ea
- & :
, - . *
- _ .
& s .
= : b 5
- > 7 Pad hd % \
- e

7 9 — i .
. =i 5 ss oo 2
ren Se 8 Pee
a == : ’ 7 oe . rs 7
he >

ee :
= .
_ = 7 we
7 as se -
. 7 oi a * 4. 7
en ramon Lae 7 al =
: 4
" Z = ~ ie a, “Se

Copepoda

Dyspontiide. Cyclopoida. Pl. LXXV.

G. O. Sars, del.

Bradypontius major, G. O. Sars, n. sp.

Copepoda

Dyspontiide. Cyclopoida. Pl, DxXeXVI-

we

‘ f
, b: pe Sy ee
W ‘
Ya ay
f fas
ea ae
Le ¥* 5 f
‘ a a
Ri ;
Be a oz
% ef * ¥ }
rg 3 2
> Re ee et
; Se Ss
te uP
\ es o: firey
\ , et E
af
¥ \ x
\ 5 ed
} See
x a
=a Wes a
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= . eat
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8
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VE ; =
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oy
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(‘i /4 a eee \
a ° \)
=
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RLS
i
a
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a

uw ———F
- 7
~ ec

Gy On sats; del:
Bradypontius caudatus, G. O. Sars, n. sp.

Copepoda

Dyspontiide. Cyclopoida. Ply Exons

G. O. Sars, del.
Cribropontius Normani (Brady).

Copepoda

Artotrogide. Cyclopoida. Pl. LXXVIII.

G. O. Sars, del.

Artotrogus orbicularis, Boeck.

Copepoda

Cancerillide. Cyclopoida. Pl. EX XTX,

G. O. Sars, del.
Parartotrogus arcticus, Scott.

. . ¢. fan SS =
eave. 96 a

Copepoda:

Cancerillide. Cyclopoida. Ply Exe

G: ©; Sars, del:

Cancerilla tubulata, Dalyell.

aie! (it a)
i . be es
ane ae’ vs he

. Be: Wo 7s eT: oe v

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Aa A dia

AN ACCOUNT

OF THE

CRUSTACEA

_ WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

BY

G-Ovc SARS

> | VOE SV
1) OO RS oP Cy es
CYCLOPOIDA

PARTS XI & XII
CLAUSIDIIDFE, LICHOMOLGIDEE (part)

WITH 16 AUTOTYPI€ PLATES

. BERGEN
Rc Bets TieaDap a he BS ER GEN MLS E UM

SOLD BY
ALB. CAMMERMEYERS’S FORLAG, CHRISTIANIA
; 1917

141
oblong oval in form, and, in addition to the apical bristles, provided with 2
finely ciliated setz on the inner edge.

Body in female of a clear yellowish grey colour, with translucent olive-
green ovarial cells and likewise greenish ovisacs; that of male highly pellucid,
exhibiting within the anterior part scattered reddish-orange oil-bubbles; eye
much larger than in female, and bright red.

Length of adult female amounting to 1.10 mm., of male to 0.90 mm.

Remarks.—The female sex of this peculiar Copepod has long been known;
but it is only in recent times that the existence of the male sex has been satis-
factorily ascertained. True, a male specimen was observed by Claus as early
as the year 1889; but its relation to Cancerilla tubulata of Dalyell was not
recognised by that author, who did not hesitate to establish for it, not only a
new species, but even a new genus. There cannot in my opinion be any doubt,
that Giesbrecht was quite right in considering Caligidium vagabundum of Claus
to be the adult male of Cancerilla tubulata, and that the description and figure
given by Canu of the supposed male Cancerilla only refer to a quite immature
specimen. The remarkable sexual dimorphism occurring in the present form
may be easily explained from the sedentary habits of the female, causing in the
latter a considerable reduction of the sensory and locomotory apparatus, and at
the same time affecting the general form of the body. |

Occurrence.—I have met with the female of this curious form occasio-
nally, off both the south and west coasts of Norway, and always attached in the
very same manner ventrally to the base of one of the arms of the common
brittle-star, Amphiura squamata. Its attachment is effected by the strongly hooked
posterior antenne, and is so firm that it is very difficult to detach it without
breaking off those appendages. It is indeed very probable that the animal
remains attached in the place it has chosen for the rest of its life, being quite
unable to move about in the water. The adult male I have taken free in the
sea in 3 different localities of the Norwegian coast, viz., at Risor and Korshavn,
on the south coast, and at Magero, outside the Trondhjem Fjord, only a single
specimen being found in each locality.

Distribution.—British Isles (Dalyell), coast of France (Canu), Mediter-

ranean, at Trieste (Claus) and Naples (Giesbrecht).

19. — Crustacea.

142,

Section 3. Poecilostoma.

General Characters.—Anterior antenne in male not hinged. Posterior
antenne without any outer ramus, and generally adapted for prehension.
Oral parts not adapted either for mastication or for suction. Mandibles
wanting. Maxille with the terminal part variously modified for conveying
food to the mouth, and provided outside with a flap-shaped setiferous palp or
exopodite. Anterior maxillipeds never prehensile. Posterior maxillipeds trans-
formed in male to powerful grasping organs. Natatory legs, as a rule, well
developed. Last pair of legs, when present, extended laterally, uni-or biarticulate.

Remarks.—The Cyclopoids comprised within this section differ materi-
ally from those included in the 2 preceding sections by the structure of the
mouth-organs, which are not adapted either for mastication or for suction,
but more properly for licking up finely dissipated nourishing particles from
the surface of various organisms or from the wall of their inner (branchial)
cavities. In accordance therewith the chief masticating organs, the mandibles,
are entirely wanting, and the number of oral appendages of course reduced
to 3 pairs only, viz., the maxilla and the 2 pairs of maxillipeds. I am
well aware that the above interpretation of the mouth-organs, which agrees,
as will be seen, with that originally set forth by Thorell, is quite at vari-
ance with the view generally adopted by recent carcinologists on the autho-
rity of Claus, according to which the usual number of oral limbs should be
present, the foremost of them representing the true mandibles. There are,
however, several serious objections to be urged against the correctness of this
altered view of the oral apparatus. Indeed, on a careful examination of the
mouth-organs in various types of the present section, I am led to the con-
clusion that the view insisted on by Claus and accepted by most recent authors
cannot be maintained, and that we must recur to the interpretation originally
given by Thorell as the only one acceptable.

As to the number of oral limbs, only 3 pairs are in reality disting-
uishable, as stated by Thorell. The assumption of the presence of a 4th pair
between the 2 anterior ones rests entirely on a miscomprehension, a part
of the foremost pair having been erroneously taken for an independent limb.
This part, generally described as a maxilla, is always found firmly attached to
the outer side of the foremost pair of limbs, and represents in reality, as opined
by Thorell, the palp or exopodite of those limbs. Though in a few cases
this exopodite may assume a somewhat maxilla-like appearance, it presents

itself in the great majority of forms as an insignificant appendage turned
backwards, or from the mouth, and attached in much the same manner as in
other Copepoda. That this foremost pair of oral limbs, together with their
palpiform appendage, cannot be regarded as the mandibles, but must represent,
as justly opined by Thorell, the true maxilla, is evident not only from their
place far behind the antennal area, but also from their relation to the oral aper-
ture. The exact position of the latter is not always easy to determine, because
it is more or less completely covered by a lamellar anterior lip; on a closer
examination, however, it will invariably be found that the said limbs are not
placed, like the mandibles, at the sides of that aperture, but decidedly behind
it, turning their extremities more or less forwards, precisely as do the maxilla
in other Copepoda. The armature also of these limbs is very different from
that generally met with in the mandibles, and in some cases at least (Clausi-
diide) exhibits an unmistakable resemblance to that found in some of the
enathostomous Cyclopoida, for instance in those belonging to the family
Cyclopide. It will finally be noticed that whereas the mandibles in several
cases are quite destitute of palps, these appendages are almost invariably found
in the maxilla. Thorell describes all the oral limbs as maxilla (m'—m’”);
but, according to the usual terminology, the 2 posterior pairs should more
properly be named maxillipeds.

About the parasitic nature of the Copepods belonging to the present
section there cannot be any doubt; but in many instances the hosts infested
by them have not yet been ascertained. The parasitism is in every case,
like that of most of the siphonostomous Cyclopoida, rather incomplete or
merely temporary, the animals being able easily to change their place and
to move freely through the water. Somewhat more sedentary are of course
the habits of such forms as live in the branchial cavity of Ascidians or
within the valves of different Mussels; though these forms also may at times
be able to leave their hosts. Only a few forms are stated to be true fish-
parasites, viz., the species of the genera Bomolochus, Ergasilus and Thersitina,
but by far the greater number seem to be confined to invertebrate animals
belonging to many different groups e. g. Echinoderms, Worms, Mollusca, Tunicata.
A number of forms belonging to this section lead a true pelagic life, being
constantly found in the open sea, and probably at times infesting some of
the larger pelagic animals. This is the case with all the known forms be-
longing to the 3 families Oncwide, Coryceide and Sapphirinide.')

1) The parasitism of some species of Sapphirina on Salpoe has long been known.
ft !

144 |

The poecilostomous Cyclopoida which up to the present are stated
to belong to the Fauna of Norway, may be referred to 6 well-defined families,
to be treated of in the succeeding pages.

Fam. 10. Clausidiide.

Characters.—Anterior division of body more or less expanded, having
the first trunk-segment wholly consolidated with the cephalon. Tail composed
of the usual number of segments. Anterior antenne 6—7-articulate. Poste-
rior antenne scarcely prehensile, being clothed at the tip with long curved
sete. Anterior lip short and broad, lamellar, with the terminal edge entire
and fringed with fine spinules. Maxille with the terminal part only slightly
curved and armed at the tip with 2 stout claw-like spines distinctly articulated
at the base, and accompanied inside by one or two coarse ciliated sete; palp
generally well developed, incurved. Anterior maxillipeds short and stout, biar-
ticulate; Ist joint very massive, 2nd small and terminating in 2 claw-like spines
accompanied by one or 2 ciliated sete. Posterior maxillipeds more slender
and 3-articulate, being generally clothed with rather long sete; those in male
very powerfully developed. Ventral face forming between the oral parts in
front 2 juxtaposed hairy lappets (lateral lips). Natatory legs, as a rule, of
normal structure, though the Ist pair in some cases (Clausidium) may be peculi-
arly moditied. Last pair of legs uni- or bi-articulate, distal joint more or less
lamellar.

Remarks.—The present family was established by E. Canu, to com-
prise the genus Hersilia Philippi and allied forms. As however the generic
name fTersilia has been preoccupied, it must be replaced by the name
Clausidium proposed by Kossman, and the family accordingly be named
Clausidiide instead of Hersiliide. It is chiefly characterised, as compared
with the other families, by the non-prehensile posterior antenne, the form of
the anterior lip, the- peculiar armature of the maxilla, and partly also by the
structure of the maxillipeds. To the Norwegian Fauna belong 2 well-defined

genera referable to this family, each represented by only a single species.

a

Gen. 36. Hemicyclops, Boeck, 1873.
Syn: Hersiliodes, Canu (part).
Platycheiron, Scott.

Generic Characters.—Body cyclopoid in shape, with the anterior division
Sharply marked off from the posterior, and more or less flattened. Tail com-
paratively slender, with the caudal rami not much produced. Anterior antenne
of moderate length and composed of 7 joints, none of which are expanded
_in front. Posterior antenne with the terminal joint very short. Maxille
provided with 2 sete inside the apical spines; palp produced inside at the
end to a well-defined small setiferous lobule. Anterior maxillipeds with several
ciliated sete in addition to the 2 apical spines. Posterior maxillipeds in female
moderately strong, but scarcely prehensile, being clothed with rather long,
partly spiniform sete; those in male powerfully developed, with the propodos
very broad and flattened and coarsely denticulated inside. Natatory legs all
of normal structure, with both rami 3-articulate. Last pair of legs biarticulate;
distal joint broad, lamellar, and edged with 3 spines and a delicate apical bristle.

Remarks.—This genus was established as early as the year 1873 by
Boeck, to include a pecfiliar Copepod found by the present author in the upper
part of the Christiania Fjord. Its true relationship to the other Cyclopoida
was however not recognised by Boeck, who placed the genus near Cyclops
within the group of gnathostomous Copepoda. The genus Hersiliodes of Canu
agrees in most characters with that here under question; but of the 3 species
recorded by him only the two, viz., H. Thompsoni and H. puffini can with
full certainty be adduced to Boeck’s genus; the 3rd species 17. Pelseneeri')
seems to me to be so different from the other 2, both as to the general form
of the body an to the structure of some of the appendages, that it hardly can
be combined with them in the same genus. If the generic name Hersiliodes
is to be retained, it must of course be restricted to that species. Of the
various species described by T. Scott, and provisionally referred to the genus
Lichomolgus Thorell, there are two which unquestionably belong to the present
genus, viz., L. littoralis and L, aberdonensis, the first of them being appa-
rently identical with the Norwegian species here described. Scott himself was
well aware of the considerable differences which these two species exhibit, as
compared with the typical Lichomolgi, and in a supplementary note’) suggested

') According to Giesbrecht, this species is identical with the form described at an
earlier date by. Grube as Antaria latericia.
) Annals of Scottish Nat. Hist. 1892, p. 153.

146
the desirability of transferring them to a particular genus or subgenus, for
which he proposed the name Platycheiron, referring to the broad and flattened
form of the propodos in the male posterior maxillipeds. This name cannot
however be accepted, as it is of much more recent date than that proposed
by Boeck.

77. Hemicyclops purpureus, Boeck.
(PI. LXXXD.

Hemicyclops purpureus, Boeck, Nye Slegter og Arter av Saltvandscopepoder, Chr. Vid. Selsk.
Forhandl. f. 1872, p. 42.

Syn: Lichomolgus littoralis, Scott.

Specific Characters —Female. Body moderately slender, with the
anterior division rather broad, oval in outline, and pronouncedly applanated.
Cephalic segment fully as long as the 4 succeeding segments combined and
narrowly rounded in front; rostral prominence incurved and obtuse at the tip.
Epimeral plates of the 3 succeeding segments expanded laterally and closely
imbricate; those of the 4th segment scarcely smaller than the others. Last
trunk-segment abruptly much smaller than the preceding ones, and not much
broader than the genital segment. Tail rather slender, equalling in length
about °/; of the anterior division, and sub-cylindric in form; genital segment
about as long as the 3 succeeding segments combined, and only very slightly
dilated in front; anal segment rather small. Caudal rami comparatively short,
though a little longer than they are broad at the base, and slightly narrowed
distally; seta of outer edge small and attached near the end; apical sete rather
unequal, the inner mediate one being, as usual, the longest, and almost
attaining the length of the tail, seta of outer corner scarcely half as long as
that of the inner. Anterior antenne about equal in length to the cephalic
segment, and gradually attenuated distally, being somewhat abruptly bent at
the base, 2nd and 4th joints the longest. Posterior antenne well developed,
penultimate joint almost as long as the preceding one and ciliated along the
anterior edge, distal corner scarcely produced and provided with a strong
curved seta and 2 bristles, one of which is ciliated; terminal joint much
shorter than the penultimate one and almost quadrangular in form, carrying
on the tip 4 strong curved sete accompanied by a few short bristles. Anterior
maxillipeds with 2 coarse sete at the end of the proximal joint inside and 2
others on the distal joint, apical spines very strong, claw-like, the outer one
armed in the middle with a well-marked denticle. Posterior maxillipeds rather
fully developed, with the middle joint angularly produced inside, and, like the

7

preceding joint, carrying 2 ciliated sete; terminal joint small, with 2 remark-
ably incurved seta accompanied by a number of thin bristles. Natatory legs
with the inner ramus considerably longer than the outer. Last pair of legs
with the proximal joint well defined and carrying outside the usual bristle;
distal joint broadly ovate, or almost spatulate in form, and densely ciliated on
both edges, marginal spines rather strong and attached to distinct ledges; apical
bristle thin and slender. Ovisacs of moderate size, narrow fusiform in shape,
and considerably divergent.

Body of a clear whitish hue, with the ovarial tubes and the ovisacs
bright red.

Length of adult female 1.15 mm.

Remarks.—This form, as above mentioned, was briefly characterised
by Boeck as early as the year 1873, and is the type of the present genus. |
have little doubt that the Lichomolgus littoralis of Scott, originally described
from a solitary male specimen, is the very same species, and this is indeed
still more confirmed by the figure subsequently given by the same author of
an adult female specimen. It is an easily recognisable form, and in the living
state highly distinguished by the bright red colour of the ovarial tubes and
the ovisacs, a character which has given rise to the specific name proposed
by Boeck.

Occurrence.—Only very few specimens of this pretty form have hitherto
come under my notice, all of the female sex. One of these specimens, that
from which Boeck’s description was made, was taken many years ago in the
upper part of the Christiania Fjord from a depth of about 20 fathoms; the other
specimens were procured in the middle part of the Fjord, at Moss, and in
about the same depth.

Distribution.—Scottish coast (Scott).

Gen. 37. Hippomolgus, G. 0. Sars, n.

Generic Characters.—Body less pronouncedly cyclopoid in shape, the
anterior division being only slightly dilated and not very sharply marked off
from the posterior. Caudal rami much produced. Anterior antenne short and
robust, 6-articulate. Posterior antenne comparatively feeble in structure. Max-
ille armed in a much similar manner to those in Hemicyclops, palp however
of somewhat simpler structure, with the sub-apical lobule very small and pro-

148

vided with only 2 unequal sete. Maxillipeds also less fully developed, with the
sete rather reduced both in size and number. Natatory legs very coarsely
developed, with some of the sete transformed in to slender spines; Ist pair not
peculiarly modified. Last pair of legs uniarticulate, the proximal joint being
wholly coalesced with the corresponding segment; distal joint comparatively
narrow, but armed in a manner similar to that in Hemicyplops.

Remarks.—This is a very distinct genus, differing in several points
rather markedly from the other known Clausidiide. It ought however evidently
to be referred to that family, as the oral parts are built on much the same
type. It comprises as yet only a single species, to be described below.

78. Hippomolgus furcifer, G. O. Sars, n. sp.
(Pl. LXXXII).

Specific Characters.—Female. Body moderately slender, with the
anterior division oblong oval in outline and scarcely applanated. Cephalic
segment occupying about half the length of the anterior division, and gradu-
ally narrowed anteriorly; rostral prominence small, but well defined. The 3
succeeding segments gradually diminishing in width, and having the epimeral
plates only slightly expanded. Last trunk-segment well developed, and almost
at broad as the preceding segment. Tail exceeding in length */3 of the an-
terior division, and rapidly tapering behind; genital segment rather massive,
and exhibiting on each side, close to the base, a small dentiform prominence;
anal segment attaining the length of the 2 preceding segments combined.
Caudal rami exceedingly slender and narrow, being more than twice as long
as the anal segment and slightly divergent, outer edge provided close to the
base with a small bristle, and at about the middle with another somewhat
larger bristle, the 2 middle apical sete well developed, the other 2 however
very small. Eye apparently wholly absent. Anterior antenne unusually short
and robust, being scarcely half as long as the cephalic segment, and clothed
with numerous diverging sete, some of which are short and curved, almost
spiniform and coarsely spinulose, others very long and slender; Ist joint rather
broad and produced in front to a short dentiform projection, behind to a
strong mucroniform spine; the 4 succeeding joints gradually diminishing in
size and lamellarly expanded in front; terminal joint simple, cylindric and
provided at the tip, in addition to the sete, with a strongly developed slender
esthetask; a similar esthetask being moreover attached to each of the
2 preceding joints. Posterior antenne comparatively feeble, though built

149

on the same type as in the other Clausidiid@, penultimate joint scarcely
half as long as the preceding one, and provided with 3 curved sete accom-
panied by a thin bristle; last joint considerably longer and carrying on the
tip 6 very long and curved sete. Anterior lip and maxille2 not much differing
in their structure from those parts in other Clausidiide. Lateral lips only
slightly indicated. Anterior maxillipeds with no sete on the proximal joint;
apical spines comparatively slender and nearly straight, being only accom-
panied by a single seta. Posterior maxillipeds rather feeble in structure, and
provided with only a few comparatively short sete; terminal joint very small,
with only 2 minute spines on the tip. Natatory legs with the rami nearly
equal in size; spines of outer ramus much elongated, especially in the 1st pair.
Last pair of legs with the free joint narrow oblong in shape, and produced at
the inner distal corner to a recurved dentiform projection, marginal spines
moderately strong, 2 of them being attached to the end of the joint, the 3rd
to a distinct ledge at about the middle of the outer edge; apical bristle rather
slender. Ovisacs of moderate size, oblong oval in form, and scarcely at all
divergent.

Colour whitish grey.

Length of-adult female 1.40 mm.

Male unknown.

Remarks.—The present form is easily recognisable from any of the
other known Clausidiidw, both by the general appearance of the body and by
the structure of the several appendages. The anterior antennz in particular
are highly distinguished by their short and®tout form and the coarse sete
clothing them.

Occurrence.—Only 3 female specimens of this remarkable form have
hitherto come under my notice. Two of them were taken in the outer part
of the Stavanger Fjord, at Bukken, from a depth of about 60 fathoms, muddy
bottom. The 3rd specimen was found at Riser, south coast of Norway, in
about the same depth.

Fam. ll. Lichomolgide.

Characters.—Body more or less pronouncedly cyclopoid in shape, the
anterior division being generally considerably dilated and sharply marked off
from the slender posterior one. Anterior antenne slender, and composed of

20. — Crustacea.

150 |

7 joints, the 2nd of which is invariably the longest. Posterior antennze more
or less pronouncedly prehensile, being armed at the tip with a varying number
of curved claws. Oral area jar remote from the antennal one, and occupying
about the centre of the ventral face of the cephalic segment. Anterior lip
deeply cleft in the midd'e or bilobate, edges of the lobes smooth. Lateral lips
absent. Maxille terminating in a lamellar falciform lappet curving anteriorly
and exserted to a thin flexible point; palp in most cases of inconsiderable
size. Anterior maxillipeds with the proximal joint naked, distal joint provided
inside with a slender spine, its end being, as a rule, exserted to a thin seti-
form lash abruptly bent at the base and turned anteriorly, with the outer edge
finely spinulose. Posterior maxillipeds more or less imperfectly developed in
female, but transformed in male to strong grasping organs. Natatory legs, as
a rule, of normal structure, though the inner ramus of the 4th pair may in
some cases be more or less reduced. Last pair of legs, as a rule, represented
on each side by a single joint extended laterally.

Remarks.—The type of the present family is the genus Lichomolgus
of Thorell, with which in recent times a number of more or less nearly allied
genera have been associated, to form a quite natural group. From the
Clausidiide this family is pretty well distinguished by the generally pronoun-
cedly prehensile character of the posterior antenne, as also by the rather
different structure of the oral parts. In these respects it agrees much more
closely with another family, viz., the Sapphirinide, and indeed, for this reason,
Thorell referred his genus Lichomolgus to that family. The external appea-
rance of the body is howevemvery unlike that met with in the said family,
being perfectly cyclopoid. Nor are there any traces of the peculiar ocular
lenses so characteristic of the Sapphirinide. The present family is well repre-
sented in the Fauna of Norway, several genera and species having been ~
observed, to be described in the succeeding pages.

Gen. 38. Lichomolgus, Thorell, 1860.

Generic Characters Anterior division of body rather dilated and pro-
nouncedly applanated, with the Ist trunk-segment in most cases defined from
the cephalon by a well-marked suture dorsally. Tail slender and composed
of the usual number of segments; the genital one in male greatly inflated.
Integuments, as a rule, very thin and soft. Anterior antenne slender and

151

narrow, 7-articulate. Posterior antenne pronouncedly prehensile, being armed
at the tip with 2 or 3 curved claws. Maxille with the terminal lappet much
produced and densely hairy on both edges; palp forming a small bi—or tri—
setose lobe turning backwards. Anterior maxillipeds with the apical lash long
and slender. Posterior maxillipeds in female short and stout, 3-articulate, and
almost naked, last joint conically produced; those in male well developed,
subcheliform, dactylus very slender and more or less strongly curved in the
middle. Natatory legs with the rami comparatively broad and nearly equal-
sized in the 3 anterior pairs; inner ramus of 4th pair however somewhat
reduced in size, and composed of only 2 joints, the distal one provided with
2 unequal spines on the tip. Last pair of legs with the free joint compara-
tively small, bisetose. Ovisacs in female very large.

Remarks.—This genus: was established by Thorell as early as the year
1860, to include 4 species found by him in the branchial cavity of various
Ascidians. I have been enabled to identify all these species, and they will be
here described and figured in detail, together with 4 additional forms, making
in all no less than 8 different species belonging to the Norwegian Fauna. In
spite of this considerable number of species, the genus is here taken in a
much more restricted sense than is done by most other authors, who refer to
it forms which in my opinion evidently are not congeneric. Some of these
aberrant forms have certainly been separated by Claus and Canu as types of
nearly-allied genera; but I think that this generic separation must be car-
ried still further. The peculiar rudimentary condition of the caudal sete
observed in the species described by Thorell cannot however properly be
regarded as a character of generic value, but is evidently due to the seden-
tary habits of these forms within the branchial cavity of Ascidians. In 3 of
the species described below, these sete, as shown by the figures, are quite
normally developed; and it is very likely that the said species do not at all
have their abode within Ascidians, but are true ecto-parasites, as has indeed
been proved as regards at least one of them (L. agilis).

79. Lichomolgus albens, Thorell.
(PI. LXXXIID.

Lichomolgus albens, Thorell, Bidrag til Kannedomen om Krustaceer som lefva i Arter af slagtet
Ascidia, p. 69, Pl. X, XI, XII: 10.

Specific Characters —Female. Body moderately slender, with the

anterior division rather dilated in front and pronouncedly applanated. Cepha-

lic segment broadly expanded, and exhibiting in its posterior part dorsally a

152

well-marked transverse suture, indicating the boundary between the Ist trunk-
segment and the cephalon. The 3 succeeding segments gradually diminishing
in size, with the epimeral plates rounded off and, as a rule, discontiguous,
being separated by well-marked lateral incisions. Last .trunk-segment very
small, not nearly as broad as the genital segment. Tail somewhat exceeding
half the length of the anterior division; genital segment fully as long as the
3 succeeding segments combined, and having its anterior part considerably
dilated and rather sharply marked off from the posterior; anal segment not
attaining the length of the 2 preceding segments combined, and scarcely longer
than it is broad. Caudal rami of moderate length and sublinear in form,
equalling in length about the last 2 segments combined, and scarcely at all
divergent; seta of outer edge well marked and attached near the middle;
apical seta much reduced in size, the 2 middle ones terminating in a very
delicate smooth filament obtuse at the tip. Anterior antenne rather slender,
about equal in length to the cephalon, and clothed with scattered curved sete
of moderate length; Ist joint considerably dilated; 2nd joint about the length
of the 2 succeding joints combined; 4th joint longer than the 5th, which
equals the 6th in length; last joint very small. Posterior antenne moderately
strong, with the 2nd joint longer than the outer 2 combined; penultimate joint
short and very oblique, with 3 small bristles in front; terminal joint slightly
dilated in the middle and armed on the tip with 2 somewhat unequal claws,
the outer one shorter, but stronger, than the inner. Maxilla with the terminal
lappet very slender and finely ciliated on both edges, palp rather small, bisetose,
with a slight notch inside the tip. Anterior maxillipeds with the proximal
spinule of the apical lash much coarser than the others. Natatory legs with
the rami rather broad; terminal joint of the outer one carrying outside in the
2 anterior pairs 3, in the 2 posterior pairs 2 spines, those in the Ist pair
coarsely denticulate in front; terminal joint of inner ramus with only a single
spine in the Ist pair and 3 spines in the 2 succeeding pairs; inner ramus of
4th pair somewhat longer than the first 2 joints of the outer combined; distal
joint attenuated, with the apical spines rather slender. Last pair of legs ex-
tremely small, being represented on each side by a minute sub-cylindric joint
with 2 slightly unequal bristles on the tip. Ovisacs very large, extending far
beyond the end of the tail, and oblong, or nearly cylindric in form.

Male of much smaller size than female, and having the anterior division
of the body less dilated. Tail, as usual, composed of 5 well-defined segments,
the foremost of which (the genital segment) is very large and tumid for the
reception of the 2 spermatophores. Posterior maxillipeds powerfully developed,

oles

with the dactylus very long and abruptly curved in the middle, tip minutely
hamate.

Body in both sexes semipellucid, of a whitish hue; ovarial tubes and
ovisacs in female of an opaque pure white colour; eye bright red.

Length of adult female amounting to 1.50 mm.; that of male scarcely
attaining 1 mm.

Remarks.—This form has been very carefully described and figured by
Thorell in his above-mentioned paper, and, as it is that species which is placed
at the head, it ought to be regarded as the type of the present genus.

Occurrence.—| have taken this form from the branchial cavity of vari-
ous Ascidians captured on the south and west coasts of Norway, most
frequently perhaps from that of Corella paralellogramma. It is generally found
attached between the lamella of the branchial sac; but it may easily change its
place. When detached, it swims about in the usual cyclopoid manner, though
by no means very rapidly. Owing to its pale semipellucid body, it is not
easy to detect, except when loaded with the large ovisacs, the opaque white
colour of which at once strikes the eye.

Distribution —Bohuslan (Thorell), British Isles (Scott), ? coast of France
(Canu), Mediterranean (Della Valle).

80. Lichomolgus forficula, Thorell.
(Pl. LXXXIV).
Lichomoigus forficula, Thorell, 1. c. p. 73, Pl. XII, XII: 19.

Specific Characters—Female. Body comparatively more slender than
in the type species, with the anterior division more regularly oval in outline,
the greatest width occurring at about the middle, Ist trunk-segment very distinctly
defined from the cephalon; last segment small, though scarcely narrower than
the genital segment. Tail very slender, even exceeding in length the anterior
division; genital segment slightly dilated in front of the middle, with the
anterior part not sharply marked off from the posterior; anal segment very
long and narrow, attaining half the length of the preceding part of the tail,
and more than twice as long as it is broad. Caudal rami exceedingly slender
and elongated, considerably exceeding half the length of the remainder
of the tail, and somewhat bent in front of the middle, carrying at this place
dorsally 2 juxtaposed delicate bristles, one of them apparently answering to
the seta of the outer edge in L. albens; distal part of the rami very narrow
and attenuated, curving generally slightly outwards; apical sete, as in L. albens,

much reduced in size. Anterior antennae comparatively shorter than in that
species, scarcely attaining the length of the cephalon, but having some of the
sete rather longer; Ist joint less broad; 2nd somewhat longer than the 2 suc-
ceeding joints combined, and slightly curved; 4th joint about the length of the
5th, which equals in length the 2 outer joints combined. Posterior antenne
shorter and stouter than in ZL. albens, with the 2nd joint rather thick and
not attaining the length of the 2 outer joints combined; apical claws 2 in
number, both rather strong, the outer one being much the longer. Max-
illa with the terminal lappet abruptly bent at the base and edged with rather
long cilia, especially at the basal curvature; palp with a small additional seta
inside the other 2. Anterior maxillipeds with none of the spinules of the
apical lash particularly strong. Natatory legs on the whole resembling in
structure those in the type species; spines of outer ramus in Ist pair however
broadly marginate, dagger-shaped. Inner ramus of 4th pair of legs scarcely
longer than the first 2 joints of the outer combined; distal joint oblong oval
in form, with the inner edge evenly curved, apical spines comparatively short,
the outer one scarcely half as long as the inner. Last pair of legs with the
free joint small, though a little more produced than in L. albens, and slightly
curved. Ovisacs oblong oval in form and extending scarcely as far as the
caudal rami.

Male exhibiting the usual sexual differences from the female.

Colour whitish, pellucid.

Length of adult female amounting to 1.40 mm.; that of male to
about 1 mm.

Remarks.—This form is at once recognised by the very slender tail,
the elongate anal segment, and the peculiar structure ot the caudal rami.
It also differs conspicuously from L. albens in some of the structural details,
and more particularly in the form and armature of the posterior antenne.

Occurrence.—| have taken this form not unfrequently from the bran-
chial cavity of Ascidia mentula and canina captured in different places on the
south and west coasts of Norway. Thorell obtained it only from the last-
named Ascidian.

Distribution —Bohuslan (Thorell), British Isles (Brady).

155

81. Lichomolgus marginatus, Thorell.
(Pl. LXXXV).

Lichomolgus marginatus, Thorell, 1. c., p. 71, Pl. XIl: 18.

Specific Characters.—Female. General form of body somewhat re-
sembling that of ZL. albens, the cephalic segment being considerably expanded
and much broader than the succeeding ones. No trace however of any sub-
division of this segment is to be detected. Tail rather slender, though not
fully attaining the length of the anterior division; genital segment sub-fusiform
in shape, being slightly dilated in the middle, with no sharp demarcation between
the anterior and posterior parts; anal segment somewhat exceeding in length
the 2 preceding segments combined, and considerably longer than it is broad.
Caudal rami slender and narrow, attaining about half the length of the remainder
of the tail, and only slightly divergent, tapering gradually to an obtuse
point, each of them having in front of the middle a very delicate bristle
arising from the dorsal face; apical sete extremely small and rudimentary,
almost obsolete. Anterior antenne of moderate length, and on the whole
agreeing in structure with those in L. forficula. Posterior antenne also rather
similar, though somewhat more elongated; apical claws longer and thinner, the
anterior one, as in that species, fully twice as long as the posterior. Maxillz
with the terminal lappet less abruptly bent at the base, and having the mar-
ginal cilia shorter and more densely crowded; palp very small with only 2
sete on the tip. Maxillipeds scarcely differing in structure from those in
L. forficula. Natatory legs also very similar; distal joint of inner ramus in
4th pair, however, somewhat less broad. Last pair of legs with the free joint
rounded oval in form. Ovisacs large, though extending only slightly beyond
the caudal rami.

Body of the usual whitish colour.

Length of adult female 1.30 mm.

Remarks.—The present species somewhat resembles in the general
form of the body L. albens, from which it is however at once distinguished
by the absence of any dorsal suture on the cephalic segment, as also by the
form of the genital segment (in female) and of the caudal rami. In the struc-
tural details it evidently comes nearer to L. forficula than to L. albens, as
shown by the figures given on the accompanying plate.

Occurrence.—Only a few female specimens of this form have as yet
come under my notice. They were selected from a number of specimens of
L. forficula, collected at different times and in different localities. I cannot,

pee

of course, state from which form of Ascidians these specimens were derived.
Thorell, who is the only author by whom this species has hitherto been ob-
served, obtained it from the branchial cavity of Ascidia venosa, and more
rarely from that of A. canina.

Distribution—Bohuslan (Thorell).

82. Lichomolgus furcillatus, Thorell.
(P]. LXXXVI).
Lichomolgus furcillatus, Thorell, 1. c., p. 74, Pl. XII: 20.

Specific Characters —Female. Body comparatively less slender than
in the 3 preceding species, with the anterior division sub-pyriform in outline.
Cephalic segment moderately expanded, and exhibiting behind a well-marked
transverse suture. Tail scarcely exceeding half the length of the anterior
division; genital segment comparatively large and somewhat dilated in the
middle, with the anterior and posterior parts well marked off from each other
laterally; anal segment rather small, broader than it is long. Caudal rami not
much produced, scarcely. exceeding in length the last 2 segments combined,
and of nearly equal width throughout; seta of outer edge well marked and
attached at about the middle; apical sete less rudimentary than in the pre-
ceding species, though scarcely ciliated, the inner mediate one almost as long
as the corresponding ramus; dorsal bristle well marked and attached near the
end. Anterior antenne about the length of the cephalon, and of the usual
appearance. Posterior antenne resembling in structure those in L. albens,
except that the proximal bristle of the penultimate joint is replaced by a strong
spine. Oral parts on the whole normal. Natatory legs likewise built on the
very same type as in the preceding species. Inner ramus of 4th pair of legs
somewhat longer than the first 2 joints of the outer combined; distal joint, as
in L. albens, attenuated in its outer part, and having the inner apical spine
rather long. Last pair of legs with the free joint comparatively larger than
in the preceding species, and exhibiting a well-marked notch in the middle
of the outer edge; both apical sete spiniform, the posterior one the longer.
Ovisacs rather large, extending far beyond the end of the tail.

Male with the posterior maxillipeds very powerfully developed, inner
edge of the propodos produced in the middle to a small papilliform promi-
nence; dactylus long and slender, being abruptly curved at some distance
from the base.

Colour whitish.

157

Length of adult female 1.30 mm.

Remarks.—| cannot doubt that the above-described form is that recorded
by Thorell as ZL. furcillatus, though the figure he gives of the female looks
somewhat different from that here reproduced. On the other hand the form
described (though rather imperfectly) by Brady under that name is certainly
very different, and would seem, judging from the figure given of the posterior
part of the body in a-female specimen, to be more properly referable to the
genus Macrocheiron, to be treated of farther on. Though nearly related
to the 3 preceding species, the present one may be easily distinguished by
the comparatively much shorter caudal rami and the form of the genital and
anal segments. The free joint of the last pair of legs also dilfers conspicu-
ously both in shape and armature.

Occurrence.—| have only met with this form in a single locality sit-
uated in the upper part of the Christiania Fjord. All the specimens were
taken from the branchial cavity of Styela intestinalis. Thorell obtained his
specimens from the same Ascidian.

Distribution.—Bohuslan (Thorell), ? Scottish coast (Scott).

83. Lichomolgus Canui, G. O. Sars, n. sp.
(PI. LXXXVII).

Syn: Lichomolgus albens, Canu (not Thorell).

Specific Characters.—Female. Body of shorter and stouter form than
in any. of the preceding species, with the anterior division oblong oval in out-
line. Cephalic segment not much expanded, being scarcely broader than the
succeeding segment, and exhibiting behind a well-marked transverse suture.
Tail about equalling in length the cephalic segment, and of a somewhat robust
appearance; genital segment rather large and massive, being considerably
tumified, with the anterior part slightly marked off from the posterior; anal
segment scarcely larger than the preceding one. Caudal rami about twice as
long as the anal segment, and somewhat divergent, being of almost equal width
throughout; seta of outer edge attached a little beyond the middle; apical
seta somewhat resembling those in L. furcillata, being less rudimentary than
in the type species. Anterior antenne about the length of the cephalon, and
somewhat less slender than in ZL. albens. Posterior antenne resembling in
structure those in the said species, but having the apical claws comparatively
longer. Oral parts scarcely differing in structure from those in L. albens.
Natatory legs also rather similar; distal joint of inner ramus in 4th pair how-

21. — Crustacea.

ioeas

ever less attenuated in its outer part. Last pair of legs with the free joint
comparatively broader than in L. albens, its posterior edge forming a con-
spicuous bulge; apical seta more unequal, the inner one rather short and
spiniform. Ovisacs oblong oval in form and somewhat divergent, extending
only slightly beyond the end of the tail.

Colour whitish.

Length of adult female about 1 mm.

Remarks.—The above-described species agrees pretty well with the
description and figures given by Canu of the form regarded by him as L. albens
Thorell. That however this identification is erroneous, is at once proved by
the figure he gives of the female, which is very unlike that given by Thorell,
whereas it agrees much better with the species here described. The present
form, it is true, is nearly allied to L. albens, but is evidently specifically distinct,
as it differs not only in the general form of the body, but also in some of the
structural details. It is also rather inferior in size.

Occurrence.—I have only recently become acquainted with this species,
2 or 3 female specimens of which were picked out from a number of L. albens
collected in different localities and from various Ascidians. It is of course
impossible for me to state from which form of Ascidian the said specimens
were derived, or at which locality they occurred. Canu states its occurrence
in 3 different Ascidians from the French coast, viz., Styela intestinalis, Molgula
socialis and Cynthia lurida. In none of these Ascidians has the true ZL. albens
as yet been found.

Distribution.— Coast of France (Canu).

84. Lichomolgus Poucheti, Canu.
(PI. LXXXVIID.

Lichomolgus Poucheti, Cauu, Copépodes du Boulonnais, p. 231, Pl. XXIII, figs. 5—12.

Specific Characters.—Female. Body somewhat resembling in shape
that in ZL. Canui, though having the anterior division comparatively broader
and regularly oblong oval or elliptical in outline. Cephalic segment large,
though not much expanded, and narrowly rounded in front, exhibiting behind
dorsally a well-marked transverse suture. Tail comparatively short, only slightly
exceeding half the length of the anterior division; genital segment not attaining
the length of the 3 succeeding segments combined, and rather tumid in its
anterior part, the greatest width equalling the length; anal segment about as
long as the 2 preceding segments combined. Caudal rami not much produced,

Jie

scarcely exceeding in length the anal segment, and slightly divergent; seta of
outer edge attached about in the middle; apical sete normally developed and
finely ciliated, the inner mediate one about the length of the tail without the
caudal rami; seta of inner corner considerably longer than that of the outer.
Anterior antenne moderately slender, about equalling in length the cephalon,
and of the usual structure. Posterior antenne with the 2nd joint scarcely as
long as the outer 2 combined; penultimate joint with the distal bristle trans-
formed into a claw-like spine; apical claws not particularly strong and 4 in number,
increasing successively in length inwards, the innermost one rather slender,
almost setiform. Maxille with the terminal lappet rather slender and edged
inside with a finely striated lamella, at the base of which a small denticle is
attached; palp comparatively larger than in most other species and projecting
at the: end, inside the apical sete, to an angular corner, in front of which a
very small additional seta is attached. Anterior maxillipeds with the proximal
spinules of the apical lash much coarser than the others. Natatory legs with
the spines attached outside the outer ramus rather small, 3 such spines occur-
ring on the terminal joint, except in the 4th pair; inner ramus of this pair
scarcely as long as the first 2 joints of the outer combined, and haviug the
distal! joint considerably narrowed in its outer part; apical spines very unequal
in length. Last pair of legs with the free joint short cylindric in form; inner
apical seta spiniform and much shorter than the outer. Ovisacs large, narrow
oblong, or almost cylindric in form, and extending far beyond the end of
the tail.

Body pellucid, with a slight yellow or orange tinge.

Length of adult female 0.90 mm.

Male unknown.

Remarks.._1 cannot doubt that the above-described form is identical
with the species recorded by Canu as L. Poucheti, though some small ditfe-
rences may be found, on comparing the figures here given with those
reproduced by Canu. It differs from all the 5 preceding species in the per-
fectly normal development of the caudal sete, indicating its freer existence as a
true ectoparasite.

Occurrence.—Only 2 female specimens of this form have as yet come
under my notice. The one of them was taken many years ago off the west
coast of Norway, at Skjerjehavn, the other at Ris6r on the south coast. Both
specimens were found in the free condition among dredged material procured
from moderate depths. Canu found this form as a semi-parasite on the sur-

siete

face of large colonies of Morchallium argus M. Edw. and Fragarium areola-
tum Giard.
Distribution.—Coast of France (Canu).

85. Lichomolgus tenuifurcatus, G. O. Sars, n. sp.
(PI. LXXXIX).

Specific Characters.—Female. Body a little more slender than in the
last-described species, with the anterior division broadly oval in outline and
pronouncedly depressed. Cephalic segments rather broad behind, but gradually
narrowed in front, and exhibiting dorsally a well-marked transverse suture, as

Joundary between the cephalon and the Ist trunk-segment, this boundary
bein’ so indicated- by a slight instriction of the lateral edges. Tail rather
slender, considerably exceeding half the length of the anterior division; genital
segment fully as long as the 3 remaining segments combined, and rather tumid
in its anterior part; anal segment about the length of the 2 preceding seg-
ments combined. Caudal rami considerably produced, being more than twice
as long as the anal segment and slightly divergent, their distal part conspicu-
ously narrowed; seta of outer edge atttached somewhat beyond the middle;
apical sete normally developed, the inner mediate one more than twice as
long as the outer, and having its distal part somewhat bent outwards; seta
of inner corner only slightly longer than that of the outer. Integuments rather
thin and soft. Anterior antenne scarcely as long as the cephalon, and built
in the usual manner, last joint very small. Posterior antenne resembling in
structure those in L. Poucheti, having a claw-like spine at the end of the
penultimate joint, and 4 apical claws, the innermost long and narrow. Oral
parts and legs likewise rather similar. Ovisacs very large, oblong in form,
and extending far beyond the end of the tail.

Body of a dark grey colour, with a slight yellow tinge, and the ovarial
tubes more opaque.

Length of adult female 1.40 mm.

Male unknown.

Remarks.—The present new species is nearly related to L. Poucheti,
as regards its structural details, but is of considerably larger size, and moreover
at once distinguished by the much more produced and narrower caudal rami,
a character which indeed has given rise to the specific name here proposed.

Occurrence—Some few female specimens of this form were taken many
years ago on the west coast of Norway, at Eggesbones, and last summer !

161 _
obtained 2 additional specimens, the one ovigerous, at Ris6r on the south
coast. All the specimens were found in the free condition among dredged
material procured from moderate depths. Although the integuments are of a
rather thin and soft consistency, somewhat similar to that found in the species
which live in Ascidians, I have little doubt that the present form, like L. Poucheti,
is in reality ectoparasitic in habits, since the caudal sete do not, as in those
species, exhibit any obliteration, but are quite normally developed. It remains
to be ascertained, however, what animals are at times infested by the
present species.

86. Lichomolgus agilis, (Leydig).
(Pll XC):
Doridicola agilis, Leydig, Zeitschr. f. wissensch. Zoologie, Vol. IV, p. 377, Pl. XIV.
Syn: Eolidicola tenax, M. Sars.
Lichomolgus doridicola, Claus.
chromodoridis, Della Valle.
concinnus, Scott.

Specific Characters.—Female. Body comparatively short and_ stout,
with the anterior division very much dilated, and rounded oval in outline.
Cephalic segment large and evenly rounded in front, exhibiting behind a well
marked transverse suture. Tail scarcely attaining half the length of the anterior
division; genital segment considerably dilated in its anterior part, and about
the length of the 3 succeeding segments combined; anal segment scarcely
larger than the preceding one. Caudal rami quite short, not even attaining
the length of the anal segment and scarcely longer than they are broad; seta
of outer edge attached near the end; apical sete well developed, the inner
mediate one being fully as long as the tail; seta of inner corner about twice
the length of that of the outer. Anterior antenne very slender, exceeding in
length the cephalon, and having the outer 4 joints remarkably long and narrow.
Posterior antenne exceedingly powerful, 2nd joint large and muscular, exceeding
a little in length the outer 2 joints combined; penultimate joint, as usual, short
and oblique, with the middle bristle transformed into a claw-like spine; apical
claws 2 in number, the interior one very strong and curved. Maxille with
the terminal lappet rather produced, and forming at the base a slight expansion
edged with small denticles; palp comparatively small, trisetose. Anterior
maxillipeds with the apical lash less abruptly bent at the base than usual, and
edged with rather slender spinules rapidly diminishing in size distally. Posterior
maxillipeds with the dactylar joint short and provided outside with a well-

See

marked ciliated spine. Natatory legs built on the very same type as in the 2
preceding species; inner ramus of 4th pair somewhat longer than the first 2
joints of the outer combined; distal joint narrowed in its outer part, with the
apical spines of moderate length. Last pair of legs with the free joint more
produced than in the other species and having the apical sete of nearly equal
length, none of them spiniform. Ovisacs large, oblong in form, and extending
far beyond the end of the tail.

Male, as usual, smaller than female, and having the anterior division
of the body somewhat less broad, being moreover easily recognised by the
greatly inflated genital segment. Posterior maxillipeds powerfully developed,
with a dense row of delicate spinules along the inner edge of the propodos;
dactylus slender and abruptly curved in the middle.

Body in both sexes semipellucid, with a violaceous or in some cases
orange tinge.

Length of adult female about 1.20 mm., of male 0.90 mm.

Remarks.—This form was described as early as the year 1853 by
Leydig under the name of Doridicola agilis. It has subsequently been observed
by several authors, and recorded under different names. In the year 1862 my
late father described it as a new form under the name Eolidicola tenax, being
unaware of Leydig’s paper, and Claus, who found that Leydig’s species ought
to be referred to Thorell’s genus Lichomolgus, recorded it as L. doridicola.
The specific name agilis, originally given to this form by Leydig, must how-
ever be retained, and this has also been done by Canu. The L. concinnus of
Scott is unquestionably identical with the present species.

It is a very distinct and easily recognisable form, being especially
distinguished by the very broad anterior division of the body, the com-
paratively short tail, and the unusually powerful posterior antenne.

Occurrence.—| have met with this form in several places, both on the
south and west coasts of Norway, and in most cases I have been enabled to
prove its parasitism on various nudibranchiate Mollusca, for instance Doris,
Eolis, Polycera. By other authors it has also been found on species belonging
to the genera Doto and Antiopa.

Distribution.—Bohuslan (Aurivillius), British Isles (Scott), coast of France
(Canu), Mediterranean (Claus).

ae

Gen. 39. Macrocheiron, Brady, 1872.

Generic Characters—Anterior division of body less pronouncedly
depressed than in Lichomolgus; cephalic segment without any distinctly defined
transverse suture dorsally. Tail slender, with the apical sete normally developed.
Anterior antenne, as in Lichomolgus, 7-articulate. Posterior antenne differing
somewhat in structure in the various species, being generally provided with
2 apical claws, the inner of which, however, may be setiform. Maxillz with
the terminal lJappet conspicuously expanded at the base, and the apical lash
more or less sharply marked off; palp with 3 or 4 small sete on the end.
Anterior maxillipeds with the apical lash less slender and less abruptly
bent at the base than in Lichomolgus. Posterior maxillipeds in female com-
paratively small, in male very powerfully developed, with the dactylus slender
falciform. Natatory legs with the inner ramus in the 3 anterior pairs well
developed and longer than the outer, in the 4th pair, however, much reduced in
size and composed of only 2 joints, which in some cases may be wholly con-
fluent. Last pair of legs with the free joint very long and slender, curving
backwards, and provided at the end inside with a slender spine, outside with
a much shorter simple bristle. Ovisacs much smaller than in Lichomolgus.

Remarks.—This genus was proposed in the year 1872 by Brady, to
include a species (M. fucicolum) found by him on the coast of Northumber-
land. The genus was subsequently withdrawn by the same author, and the
species upon which it was founded referred to the genus Lichomolgus of
Thorell. I think however that there are reasons for restoring the genus in
question, as it exhibits several well-marked distinguishing characters indicated
in the above diagnosis. Two well-defined Norwegian species referable to this
genus will be described in the sequel, and I have also had an opportunity of
examining. a 3rd species obtained during the Monaco-Expedition from the
Sargasso Sea.. Moreover several of the exotic species described by A. Scott
and referred bv him some to the genus Lichomolgus and some to the genus
Pseudanthessius, may more properly be included in the present genus.

87. Macrocheiron fucicolum, Brady.
(Pir XD:
Macrocheiron fucicolum, Brady, Nat. Hist. Trans. Northumberland and Durham, Vol. IV, p. 434,
Pl. XVII, figs. 9—18.

Syn: Lichomolgus fucicolus, Brady.
Specific Characters —Female. Body moderately slender, with the
anterior division not much dilated, being regularly oblong oval in outline, and

164

rather strongly vaulted dorsally. Cephalic segment about twice as long as the
3 succeeding segments combined, and scarcely exhibiting the slightest trace
of a dorsal suture; rostral prominence well defined and pointed at the end.
Tail only slightly exceeding half the length of the anterior division; genital
segment rather large, occupying almost half the length of the tail, and con-
spicuously dilated in front of the middle; anal segment scarcely as long as the
preceding one. Caudal rami not much produced, though somewhat longer than
the anal segment, and only very slightly divergent; seta of outer edge attached
at a short distance from the end; apical sete not much produced, the inner
mediate one only slightly exceeding half the length of the tail. Anterior
antenne moderately slender and clothed with scattered comparativeiy short
sete; 2nd joint, as usual, the longest, though scarcely attaining the length of
the 2 succeeding joints combined; last joint fully as long as the penulti-
mate one. Posterior antenne unusually sho and stout, and apparently
composed of only 3 joints, the outer 2 being wholly confluent; Ist and
2nd joints very massive and of about equal size, each having outside a
well-marked seta; distal part of the antenna (the combined 2 outer joints)
rather narrower than the proximal part, but of about the same length, and pro-
vided outside with a denticulated spine and 2 unequal sete, at the tip with
several curved sete, one of which is somewhat stronger than the others and
may represent the inner claw, the outer claw being exceedingly strong, knife-
shaped and irregularly denticulate along the outer sharpened edge. Maxillary
palp comparatively small but provided with 4 seta. Anterior maxillipeds with
the distal joint larger than usual; apical lash comparatively short and having
the margin coarsely dentate at the base. Posterior maxillipeds rather feeble,
but exhibiting a very conspicuous armature, 2 rather strong, almost claw-like
spines being attached to the inner edge of the propodal joint and a similar,
though smaller spine inside the dactylar joint. Natatory legs with the rami
comparatively slender and having the spines narrow dagger-like; terminal joint
of inner ramus in Ist pair obliquely oval in form, with the spine of the outer
edge attached close to the apex. Inner ramus of 4th pair rather small, not
nearly attaining the length of the first 2 joints of the outer combined, and
biarticulate, proximal joint without any seta inside, distal joint slightly attenu-
ated, with the apical spines very unequal in length. Last pair of legs with
the free joint very long and narrow, slightly curved and quite smooth outside.
Ovisacs oval in form and slightly divergent, extending scarcely beyond the tail.

Male, as usual, of smaller size than female, and moreover easily recog-
nisable by the greatly inflated genital segment. Posterior maxillipeds very

eae

powerfully developed, with the propodos large and fringed inside with a dense
row of delicate spinules; dactylus slender falciform and abruptly bent at
the base.

Body in female semipellucid, with a more or less distinct yellowish
brown tinge, and the segments partly edged behind with a light rosy pigment;
ovarial tubes and ovisacs dark green.

Length of adult female amounting to 1.20 mm., of male to 0.90 mm.

Remarks._-This form was recorded as early as the year 1872 by Brady
under the above name, and was subsequently redescribed by the same author
in his well-known Monograph as a species of the genus Lichomolgus. It is
an easily recognisable form, differing from most other Lichomolgide, both as
to the general appearance and to the structure of some of the appendages,
for instance the posterior antenne.

Occurrence._| have taken this form in many places, both on the west
and south coasts of Norway, as also in the upper part of the Christiania Fjord.
It is generally found in moderate depths among algz and other marine growths,
and always in the free condition. Indeed, it is not improbable that, as sugges-
ted by Brady, it derives its food to a great extent from the juices of the alge
or from small particles licked up from the surface of their fronds.

Distribution—British Isles (Brady).

88. Macrocheiron hirsutipes (Scott).
(PI. XCIl).

Lichomolgus hirsutipes, Scott, Eleventh Ann. Rep. of the Fishery Board for Scotland,
Part Ill, p. 206, Pl. IV, figs. 1—12.

Specific Characters —Female. Body a little more slender than in the
preceding species, though having the anterior division comparatively broader
and less vaulted. Cephalic segment large, fully twice as long as the 3 suc-
ceeding segments combined, and exhibiting a very slight indication of a trans-
verse suture behind. Last trunk-segment very narrow and sharply marked off
form the preceding one. Tail rather slender, considerably exceeding half the
length of the anterior division; genital segment comparatively large and dilated
in front of the middle, with the posterior cylindric part sharply marked off
from the anterior; anal segment a little larger than the preceding one. Caudal
rami resembling in structure those in the type species. Anterior antenne also
rather similar, though somewhat more elongated, with the penultimate joint
longer than the terminal one. Posterior antenne rather unlike those in the

22. — Crustacea.

166

type species, being much more slender, and having all 4 joints well defined;
2nd joint considerably longer than the Ist, and about equal in length to the
last 2 combined; penultimate joint, as usual, quite short and provided at the
outer distal corner with a slender spine and 2 unequal sete; terminal joint
narrow cylindric in form, and armed at the tip with 2 simple subequal claws
accompanied by a number of small sete. Maxillar palp with only 3 sete.
Anterior maxillipeds with the distal joint less robust than in the type species.
Posterior maxillipeds comparatively thicker, with only 2 simple unequal sete
inside the propodal joint. Natatory legs on the whole resembling in structure
those in the type species; inner ramus of 4th pair, however, comparatively
larger, exceeding in length the first 2 joints of the outer combined, and having
a well-marked, though rather short seta inside the proximal joint. Last pair
of legs with the free joint considerably produced and strongly curved, its outer
face densely hairy.

Body semipellucid with a slight yellow or orange tinge.

Length of adult female 1.30 mm.

Remarks.—The present form, described by Scott as a species of the
genus Lichomolgus, is unquestionably congeneric with the preceding species,
though differing conspicuously in the structure of the posterior antenne. The
specific name given to it refers to the peculiar hairy coating, in the female,
of the free joint of the last pair of legs.

Occurrence.—Only 3 female specimens of this form have hitherto come
under my notice. One of them was taken many years ago on the west coast
of Norway, at Eggesbenes, the other 2 at Risor, on the south coast. All 3
specimens were found in the free condition among dredged material taken up
from moderate depths.

Distribution.—Scottish coast (Scott), Novaja Zemlja (Scott).

Gen. 40. Pseudanthessius, Claus, 1889.

Generic Characters.—Body of rather varying form in the different
species, with the anterior division more or less expanded and well marked off
from the posterior. Cephalic segment with only slight traces of a subdivision.
Anterior antenne of normal structure, 7-articulate. Posterior antenne distinctly
4-articulate, with 3 apical claws, which in some cases are short, in other cases
very slender, almost setiform. Maxille with the terminal lappet blade-like,

167

gradually attenuated towards the end; palp tri-setose. Maxillipeds of normal
‘Structure. Inner ramus of 4th pair of legs uniarticulate. Last pair of legs
quite rudimentary, each being replaced by a simple spine accompanied by 2
small bristles.

Remarks.—-This genus, established by Claus, is chiefly characterised by
the rudimentary condition of the last pair of legs. Another character on which
still more stress has been laid by recent authors, is the reduction of the inner
ramus of the 4th pair of legs to a single joint. This character is, however,
not peculiar to the genus Pseudanthessius, but is also found in some species
of the genus Macrocheiron. Thus in the species mentioned above from the
Sargasso Sea, which in all other respects is closely allied to M. fusicolum,
the 2 joints of this ramus are wholly coalesced; and the same is also the case
with some of the Ceylon species described by A. Scott and, on account of
that character, erroneously referred to the genus Pseudanthessius, though from
the structure of the last pair of legs and other characters they must evidently
be included in the genus Macrocheiron, as here defined. 4 Norwegian species
referable to the present genus will be described below.

89. Pseudanthessius gracilis, Claus.
(PI. XCIII).

Pseudanthessius gracilis, Claus, Arbeiten d. zool. Inst. Wien, Vol. VIII, p. 344, PI. IV, figs. 1 —7.

Specific Characters. Female. Body rather slender, with the anterior
division moderately dilated and oblong oval in outline, greatest width in front
of the middle. Cephalic segment large, fully twice as long as the 3 succeeding
segments combined, and narrowly rounded in front. Last trunk-segment slightly
produced on each side. Tail very slender, somewhat exceeding half the length
of the anterior division; genital segment scarcely longer than the 3 succeeding
segments combined, and gradually widening posteriorly for about °/s of its
length, then abruptly contracted, the hind third part being cylindric in form
and scarcely broader than the succeeding segment; anal segment nearly twice
as long as the preceding one. Caudal rami very slender and narrow, equalling
in length about half the remaining part of the tail, and scarcely at all diver-
gent; seta of outer edge attached near the middle; apical sete rather unequal
in length, the 2 middle ones being much longer than the other 2. Anterior
antenne comparatively slender and clothed with moderately long sete; 2nd
joint, as usual, the longest; terminal joint scarcely more than half as long as
the penultimate one. Posterior antenne moderately strong, with the 2nd joint

the largest, and considerably exceeding in length the outer 2 combined; apical
claws rather slender and of nearly equal length, though successively coarser
inwards. Maxille with the terminal lappet evenly attenuated and almost quite
smooth. Anterior maxillipeds with the apical lash coarsely denticulated in its
proximal part; lateral spine of distal joint attached near the base of the joint
and accompanied by a short seta. Posterior maxillipeds rather coarse, with
the Ist joint fully as long as the other 2 combined; propodal joint armed
with a strong ciliated spine inside in the middle; dactylar joint claw-like, with
a well-marked spine outside the base. The 3 anterior pairs of natatory legs
normally developed, with the rami slightly unequal in length, the inner one
being the longer; all spines coarsely denticulate. 4th pair of legs with the
outer ramus more slender than in the preceding pairs, and wanting one of the
spines on the terminal joint; inner ramus shorter than the first 2 joints of the
outer combined, and exhibiting outside in the middle a well-marked notch; apical
spines narrow dagger-shaped and rather unequal in length, the inner one
being nearly twice as long as the outer. Last pair of legs, as in the other
species of the present genus, replaced on each side by a spine inserted
directly on the corresponding segment and accompanied by 2 small sete, the
spine in the] present species being rather slender and exhibiting at the base a
slight dilatation. Ovisacs not very large, fusiform in shape, and considerably
divergent.

Colour yellowish brown.

Length of adult female amounting to 1.30 mm.

Male unknown.

Remarks.—This is the species upon which Claus founded his genus
Pseudanthessius, and it ought accordingly to be regarded as the type of the
present genus. In the slender form of the tail and the narrowly-produced caudal
rami, this species bears much resemblance to the form recorded by Brady as
Lichomolgus Thorelli, and indeed I at first believed the two to be identical.
T. Scott, however, regards them as distinct, and the detail-figures given by Brady
exhibit in reality some points of difference, especially as regards the form of
the genital segment and the relative size of the inner ramus of the 4th pair
of legs. A redescription of Brady’s species would however be very desirable.

Occurrence.—I have met with this form occasionally in several places,
both on the south and west coasts of Norway. All the specimens were of the
female sex, and were found in the free condition among dredged material
taken up from moderate depths.

Distribution —British Isles (Scott), Mediterranean (Claus), Ceylon (A.Scott).

169

90. Pseudanthessius liber, (Brady).
(PI. XCIV).

Lichomolgus liber, Brady, Monogr. of British Copepoda, Vol. 111, p. 44, Pl. LXXXVI,
figs. 1—13.

Specific Characters.Female. Body comparatively robust, with the
anterior division considerably tumefied and rounded oval in outline, greatest
width about in the middle. Cephalic segment very large, with a slight indi-
cation of a transverse suture behind the middle. Last trunk-segment, as usual,
very sharply marked off from the preceding one and rather narrow. Tail com-
paratively short, scarcely attaining half the length of the anterior division;
genital segment about as long as the 3 succeeding segments combined and
slightly dilated in its anterior part; anal segment about the length of the
preceding segment. Caudal rami rather short, scarcely longer than the anal
segment, and slightly divergent; seta of outer edge attached near the end;
apical sete less unequal than in the type species, those of the outer and
inner corner being well developed, though somewhat shorter than the 2 middle
ones. Anterior antennae not much elongated and only slightly attenuated,
being clothed with comparatively short and thick sete; the outer 2 joints
rather small, and combined about the length of the antepenultimate one.
Posterior antenne scarcely shorter than the anterior ones and comparatively
strongly built, the first 2 joints rather thick and massive, subequal in size,
and combined occupying about half the length of the antenna; last joint
cylindric in form, and provided at the end with several sete in addition to
the claws; the latter rather short, but somewhat unequal in size, one of them
being much stronger than the other 2. Maxille with the terminal lappet
rather produced, and fringed along the posterior edge with delicate spinules;
palp with a very small seta inside, in addition to the 3 apical ones. Anterior
maxillipeds with the apical lash less abruptly bent at the base than in the
type species, and less coarsely denticulate at the edge. Posterior maxillipeds
comparatively smaller, with only a simple seta inside the propodal joint;
dactylar joint conically produced. Ist pair of natatory legs with the proximal
joint of the basal part remarkably expanded outside, Ist joint of outer ramus
much broader than the other 2, and having the spine of the outer edge rather
produced. Inner ramus of this and the 2 succeeding pairs somewhat longer
than the outer; that of 4th pair, however, scarcely as long as the first 2 joints
of the outer combined, and forming a single oblong fusiform joint without
any notch outside, apical spines rather unequal, the inner one being much

170

the longer. Last pair of legs exhibiting a rudimentary condition similar to
those in the preceding species, the spine being however less slender, almost
knife-shaped, and pointing backwards. Ovisacs of moderate size, oblong oval
in form, and closely applied to the sides of the tail.

Male much smaller than female, and exhibiting the usual sexual
differences. Dactylus of the posterior maxillipeds very slender and abruptly
curved in the middle, terminating in a small knob-like dilatation.

Body in both sexes of a whitish grey colour, with a more or less
distinct violaceous tinge.

Length of adult female amounting to 1.30 mm., of male to 0.90 mm.

Remarks.—This form was announced as early as the year 1875 by
Brady and Robertson, and was subsequently more fully described and figured
by the former author in this well-known Monograph as a species of the genus
Lichomolgus. Canu was the first to recognise the true systematic position of
this form within the genus Pseudanthessius of Claus. From the type of this
genus, P. gracilis, it is at once distinguished by the short, compact shape
of the body, in which respect it exhibits a perplexing similarity to an other-
wise ‘very different form, viz., Echinocheres violaceus belonging to the sipho-
nostomous Cyclopoida (compare the figure here given with that of the latter
form on Pl. LVIII).

Occurrence.__| have met with the present form in several places, both
on the west and south coasts of Norway, as also in the upper part of the Chri-
stiania Fjord. It is not unfrequently found in the free condition among dredged
material, and this indeed induced Brady to give it the rather inappropriate
specific name liber. I have however, in several instances been enabled to
ascertain its parasitic nature, having found it not unfrequently in considerable
numbers clinging to the surface of various Echinids, for instance Echinus
sphera and Strongylocentrotus drébakiensis.

Distribution. British Isles (Brady), Ceylon (A. Scott).

91. Pseudanthessius assimilis, G. O. Sars, n. sp.
(PI. XCV).

Specific Characters. Female. Very like the preceding species, but of
much larger size, and having the anterior division broader in front than behind. ©
Tail considerably exceeding half the length of the anterior division; genital
segment comparatively large, and of a similar form to that in P. liber; anal
segment, however, much (nearly twice) larger than the preceding segment.

2D.

Caudal rami also considerably more produced, being fully 3 times as long as
they are broad, and scarcely at all divergent; seta of outer edge rather slender,
and attached at a short distance from the end; apical sete well developed and
not very unequal. Anterior antenne, as in P. liber, rather robust, and clothed
with comparatively short and thick curved seta. Posterior antenne built on
the very same type as in that species, though having the distal part compara-
tively more slender. Oral parts and legs almost exactly as in P. liber. Ovisacs
comparatively large, extending considerably beyond the end of the tail.

Male with the genital segment greatly inflated and terminating on
each side in an acuminate lappet. Posterior maxillipeds transformed in an
altogether similar manner to that in the male of P. Jiber.

Body in both sexes of whitish colour, with a slight rosy or orange tinge.

Length of adult female amounting to 1.85 mm., of male to 1.35 mm.

Remarks.—The above-described form is closely allied to P. liber, and
indeed at first I regarded it as only a variety of that species. On a closer
examination, however, I have found that it differs in some points so decidedly
as to be more properly considered specifically distinct. It is also of much larger
size, aS is seen from the habitus-figures of both, which are drawn on the very
same scale.

Occurrence.—| have met with this form in 2 rather remote places on
the Norwegian coast, viz., in the outer part of the Romsdal Fjord, at some
distance from Molde, and in the inner part of Hardanger Fjord, at Sunde. In
both places it was found in considerable numbers clinging to the surface of
the beautiful deep-water Echinid, Echinus elegans, taken up from the great
depth of 150—200 fathoms.

92. Pseudanthessius Sauvagei, Canu.
(PI. XCVD).

Pseudanthessius Sauvagei, Canu, Copépodes de Boulonnais, p. 243, Pl. XXV.

Specific Characters.-Female. Body comparatively short and _ stout,
with the anterior division sub-compressed, being greatly vaulted above and,
viewed dorsally, narrow oblong in outline, the greatest width scarcely exceeding
half the length. Cephalic segment occupying almost °/; of the length of the
anterior division, and exhibiting scarcely any trace of a subdivision. Last
trunk-segment very small. Tail not attaining half the length of the anterior
division, and almost perfectly cylindrical in form; genital segment scarcely at
all dilated, but rather long, occupying about half the length of the tail; anal

13

segment of about the same size as the preceding one. Caudal rami comparatively
short, but rather broad and transversely truncated at the end, being scarcely
at all divergent; seta of outer edge attached near the end; apical sete well
developed and not very unequal in length. Anterior antenne scarcely
exceeding half the length of the cephalic segment, and distinguished by the
great length of some of the sete clothing them; 2nd joint comparatively
shorter and thicker than in the other species; last joint very small. Posterior
antenne rather feeble in structure, though not much shorter than the anterior;
2nd joint not attaining the length of the outer 2 combined, and finely ciliated
on the inner edge; apical claws very slender and not much stronger than the
accompanying sete, the outermost being the longest. Maxille agreeing in
structure with those in the type species. Anterior maxillipeds also rather
similar. Posterior maxillipeds however less strong, with the propodal joint
the longest and somewhat curved at the base, carrying inside beyond the
middle a very long recurved plumose seta; dactylar joint conical in form. The
3 anterior pairs of natatory legs with the rami rather coarse and of about equal
length. 4th pair with the outer ramus much more slender than in the pre-
ceding pairs and, as usual, wanting one of the spines on the terminal joint;
inner ramus somewhat exceeding the length of the first 2 joints of the outer
combined, and rather broader, with a small, but distinct notch outside a little
in front of the middle; apical spines rather thin and nearly equal-sized, or the
outer one a little longer than the inner. Last pair of legs, as in the other
species, replaced on each side by a rather strong posteriorly-pointing spine
and 2 small sete.

Colour not yet ascertained.

Length of the specimen examined about 1 mm.

Remarks. The above-described form agrees on the whole pretty well
with the description and figures given by Canu of his species, and | cannot
therefore doubt the identity of the two. It is an easily recognisable species, being
especially distinguished by the peculiar compressed form of the anterior division of
the body, making it rather difficult to get a dorsal view of the animal. In some of
the structural details also it exhibits well-marked differences from the other species.

Occurrence.—Only a solitary female specimen of this form has as yet
come under my notice. It was found, some years ago, at RisGr, south coast
ol Norway, being selected from some dredged material obtained from a depth
of about 20 fathoms. Canu has stated the occurrence of this species as a
parasite on the well-known Spatangoid, Echinocardium cordatum.

Distribution.— Coast of France (Canu).

Copepoda.

Pl. LXXXI.

Cyclopoida.

Clausidiide.

G. O. Sars, del.

Hemicyclops purpureus, Boeck.

Copepoda.

Clausidiidee. Cyclopoida. Pl. LXXXII.

fare

ee.

G.“O. Sars, del.
Hippomolgus furcifer, G. O. Sars.

ae
Se
Bes
.

\ art (4 Chew st ;
2 . ay eis =

ar ee al
at Te ee
: a f i, ea ie

f
ve es “a« a,
in

= ahah a
ar!
>

e

pee a valt =

eee es ;
vo Ay ; Puree oh sre et BN A :
oe het ie io ok LE St : gt bt stan

a | Wes (ar ge ee eae oar) Te, _ er
ae wis ¥ nS) wes em ee nie =f

vata

Pi Er
+ eee
hea Bae

Copepoda.

Lichomolgida. Cyclopoida. PI. LXXXII.

G. O. Sars, del.

Lichomolgus albens, Thorell.

*
@

bral < :
eit RT 2 Pun ~
Heo ae NaS) CPN ay

w

: (od + Ky a! y

c » a uaae a: fs is ;
i ; A Ne
v, ;

: 4
nn ¥ ty
secs Dia

i

— a
hoist 1 A ie cal
ie Satins Rv ante ta 1 ste MAM

Copepoda.

LXXXIV.

Pl.

Cyclopoida.

Lichomolgide.

G. O. Sars, del.

Lichomoigus forficula, Thorell.

ois
“

“time

‘ aE a
Vid ee

Copepoda.

LXXXV.

Cyclopoida. Pl.

Lichomolgida.

G. O. Sars, del.

Lichomolgus marginatus, Thorell.

ap

res

7 ‘a
*

Sra hi
ae tu
a ,. z
rid aL)
5,

Copepoda.

LXXXVI.

Pls

Cyclopoida.

Lichomolgide.

Pi AL/,

G. O. Sars, del.

Lichomolgus furcillatus, Thorell.

ae ie :
=, aan ee
ire

sass? *

sagt |
A

fone 4

rs . isi
ied AAO ri

Copepoda.

Lichomolgide. Cyuclopoida. Pl. LXXXVII.

6. O. Sars, del.

Lichomolgus Canui, G. O. Sars.

Ba ok a oA
ry ee Wiel atid
| a : ty 7 ‘ak ) F an .

on

Me
i

a pies
neti:
Ts an

aur
TRA ved

" ‘ee *
¥ A, ee ae
seers | ghee
ry Lore ~

‘

am ae
es het ;
oe aa Oe

Orr ar Cane

Copepoda.

Pl. LXXXVIII.

Cyclopoida.

Lichomolgide.

G. O. Sars, del.

Lichomolgus Poucheti, Canu.

he eS
eet

eae aa
Serie ha ay

a)

jens! a hy

rea kas! =
Ast She on sty
Y) y ea a

Copepoda.

Pl. LXXXIX.

Cyclopoida.

Lichomolgida.

G. O. Sars, del.

Lichomolgus tenuifurcatus, G. O. Sars.

a,
Ae te i?

Vte
i iv
jue a ‘¢ i
has Kiri
- My lar loa = if
A i ie ia a -
Bo Ae %:

Nay

L,
4 anys

Copepoda.

PI xX:

Cyclopoida.

Lichomolgide.

G. O. Sars, del.

Lichomolgus agilis, Leydig.

4% fee
9 ie

Ue

Aa

a

be

XCl.

Pi.

Copepoda.
Cyciopoida

Lichomolgida.

G. O. Sars, del.

Macrocheiron fucicolum, Brady.

f at

ek ales a

Copepoda.

Lichomolgida. Cyclopoida. Pl. XCIl.

G. O. Sars, del.

Macrocheiron hirsutipes (Scott).

Copepoda.

XCIll.

Cyclopoida. Pl.

Lichomolgide.

Niiceasateenesindusooeen ioe ee

a ————

G. O. Sars, del.

Pseudanthessius gracilis, Claus.

jane h,
I if Pius A see aC

ie
i

ey

j
nt

Copepoda.

XCIV.

Cyclopoida. Pl.

Lichomolgide.

G. O. Sars, del.

Pseudanthessius liber (Brady).

*
a
2)

==

Copepoda.

Lichomolgidee. Cyclopoida. PI. XCV.

A A
Gyre TED. ©

eee —_

G. O. Sars, del.
Pseudanthessius assimilis, G. O. Sars.

Le
)
t

me i

Copepoda.

XCVI.

Cyclopoida. Pl.

Lichomolgide.

G. O. Sars, del.

Pseudanthessius Sauvagei, Canu.

Bs Poi
i ig
7 wee
tot

¥ eda 2, : ? ‘a= i Ce ‘Prag.

A NS Saw A, ee oe 7 ite ae Seas
a aaety yy. 4 Pkg Be S (Wy othe Gale amen
Tee ee on° 4.5 A eee Weare wena : Tes ‘ i. ay’ ert

Te n ilo ane .
* > a : . ech Geme : -"

7
it

. ’

4
Pa

a

a .
Lh |
oe. a)

ls > ao
Red? 6

AN ACCOUNT.

OF THE ~

-CRUSTACEA

NO = WAY
oe "WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES
oo Bye
G. O. SARS
| = VOL, WI
Lé ORE OD AX
CY C LOP OIDA

=" Pa

PARTS XIll & XIV

LICHOMOLGIDFE (concluded), ONCfEIDAE, CORYCAEIDAE, ERGASI-
-——— LIDAE, CLAUSIIDAE, EUNICICOLIDAE, SUPPLEMENT

WITH 22 AUTOTYPIC PLATES

£ BERGEN
PUBLISHED BY THE BERGEN MUSEUM

: : : SOLD BY
ALB. CAMMERMEYERS'S FORLAG, CHRISTIANIA
1918

May

Gen. 41. Modiolicola, Aurivillius, 1883.

Generic Characters Anterior division of body moderately dilated and
more or less depressed, with the Ist trunk-segment well defined from the
cephalon. Tail slender and attenuated. Integuments thin and soft. Anterior
antenne 7-articulate and of a structure similar to that in the preceding genera.
Posterior antenne slender and almost naked, with the penultimate joint unusu-
ally prolonged; apical claws 3 in number. Maxille with the terminal lappet
much produced, falciform; palp small, tri-setose. Anterior maxillipeds without
the usual lateral spine on the distal joint. Posterior maxillipeds in female
much reduced, in male well developed, prehensile. Natatory legs with both
rami 3-articulate in all the pairs; inner ramus of 4th pair with no sete inside
the terminal joint. Last pair of legs uniarticulate, bisetose.

Remarks.—This genus was established in the year 1883 by Aurivillius,
to include a peculiar Copepod found by him parasitic within the valves of the
well-known mussel Modiola vulgaris. The genus is chiefly distinguished
from those treated of in the preceding pages by the distinctly 3-articulate inner
ramus of the 4th pair of natatory legs, and partly also by the structure of the
posterior antenne. Otherwise this genus is rather closely allied to Lichomolgus.
In addition to the type species described below, Canu has recorded another
species under the name of M. inermis. Only the type species has been
observed by me.

93. Modiolicola insignis, Aurivillius.
(PI. XCVII).

Modiolicola insignis, Aurivillius, Bidrag til Kannedomen om Krustaceer, som lefva hos Mollusker
och Tunicater, p. 10 & 39, Pl. Il, figs. 1—10, Pl. IV, figs. 1—8.

Specific Characters.—Female. Body moderately slender, with the
anterior division rather expanded, rounded oval in outline, and pronouncedly
flattened. Cephalic segment large and slightly produced in front, exhibiting
behind a very distinct transverse suture limiting the cephalon from the Ist
pedigerous segment. Epimeral plates of the 3 succeeding segments evenly
rounded off. Tail equalling in length 7/3; of the anterior division; genital seg-
ment about the length of the 3 succeeding segments combined, and some-
what tumid in its anterior part, which is rather sharply defined from the
cylindrical posterior part; anal segment a little smaller than the preceding one.

23.—Crustacea,

174

Caudal rami scarcely longer than that segment, and not at all divergent; seta
of outer edge attached about in the middle; apical setae comparatively short.
Anterior antenne about the length of the cephalon and rather narrow, being
clothed with comparatively short anteriorly-curving sete. Posterior antenne
unusually slender and attenuated, almost nacked, except at the tip, which
carries 3 strongly curved claws accompanied outside with 2 sete. Posterior
maxillipeds without any armature whatever, terminal joint small, tuberculiform.
Natatory legs well developed, with the rami subequal in length; inner ramus
of 4th pair fully as large as that of the preceeding pairs, but only provided
with 2 seta and 2 spines, the latter attached to the end of the terminal joint.
Last pair of legs with the free joint rather small, sub-cylindrical in form, and
carrying on the tip 2 very unequal sete, the inner one much the larger and
curved backwards. Ovisacs comparatively large, oblong in form, and only
slightly divergent.

Male much smaller than female, and having the anterior division of
the body less expanded. Genital segment greatly tumefied. Posterior max-
illipeds powerfully developed, with the apical claw very long and slender.

Body of female semipellucid, with the ovarial tubes of a bright rosy
colour; ova in the ovisacs reddish orange.

Length of adult female 1.40 mm., of male 1.00 mm.

Remarks.—This form was first described by Aurivillius, and has sub-
sequently been recorded by several other authors. It is the type of the
present genus.

Occurrence.—|I have found this form not unfrequently within the pallial
cavity of large specimens of Modiola modiolus taken in the outer part of the
Christiania Fjord, at Hvalor. Aurivillius has also occasionally obtained it from
Mytilus edulis.

Distribution —Bohuslan (Aurivillius), British Isles (Scott), coast of France
(Canu), Mediterranean (Raf. Monticelli).

Gen. 42. Hermannella, Canu, 1891.

Generic Characters.—Body of somewhat different form in the different
species, and having the integuments well chitinised, cephalon more or less
distinctly defined from the Ist pedigerous segment, and produced in front to
a well-marked incurved rostrum. Tail attenuated, with the genital segment in

175

female scarcely subdivided. Anterior antenne of the usual structure, 7-arti-
culate. Posterior antenne more or less strongly developed, in some cases
pronouncedly prehensile, in other cases imperfectly prehensile. Oral parts on
the whole of normal structure, the posterior maxillipeds in female having the
dagtylar joint well developed, spiniform. Natatory legs with both rami distinctly
3-articulate; inner ramus of 4th pair however in most cases somewhat smaller
than in the other pairs. Last pair of legs comparatively small, bisetose.
Remarks.—This genus, established by Canu, is nearly allied to Modioli-
cola; but differs in the more strongly chitinised integuments, the well defined
rostrum, and the somewhat unlike structure of the posterior antenne and the
posterior maxillipeds. 5 species referable to this genus will be described in
the sequel. All these have been found occasionally among dredged material;
but is is very likely to believe, that they in reality, like the species of the
preceding genus, lead a semiparasitic existence, probably within different
bivalve Molluscs. This has indeed been stated to be the case with the type
of this genus, Hermannella rostrata Canu, as also with H. maxima (Thomps.).

94. Hermannella valida, G. O. Sars, n. sp.
(Pl. XCVII).

Specific Characters —Female. Body rather stout and robust, with the
anterior division considerably dilated in front, its greatest width equalling about
half the length of the body. Cephalic segment very large and expanded,
exhibiting behind a rather slight transverse suture defining the cephalon from
the 1st pedigerous segment, lateral edges evenly curved throughout. Epimeral
plates of the 2 succeeding segments obtusely rounded, those of penultimate
segment acutely produced. Last segment of trunk very small. Tail compara-
tively short, scarcely longer than the 4 free trunkal segments combined; genital
segment occupying about half the length of the tail, and somewhat dilated in
the middle; anal segment considerably longer than the preceding one. Caudal
rami much shorter than that segment, and only slightly longer than they are
broad, each having close to the base outside a small bristle; caudal sete not
much different in length, that of the outer edge attached near the end. Anterior
antenne rather slender and of quite normal structure. Posterior antenne very
powerfully developed and pronouncedly prehensile, Ist joint much the largest
and obliquely produced at the end; the 3 succeeding joints successively
diminishing in size, the last one armed at the end with a single very strong
claw accompanied by a number of unequal sete, Maxille with the masticatory

B28

lappet densely hairy and exserted to a slender setilorm lash; palp provided at
the end with 3 seta, the innermost very small. Anterior maxillipeds with the
terminal process only slightly curved and having 3 of the denticles stronger
than the others. Posterior maxillipeds of moderate size, propodal joint scar-
cely as long as the basal one and provided inside, about in the middle, with
a short seta; dactylar joint conical in form and having outside a slender spine.
Inner ramus of the 3 anterior pairs of natatory legs somewhat longer than the
outer; that of 4th pair however rather shorter, with the terminal joint narrow
sublinear in form and only provided with 2 unequal spines, both issuing from
the end. Last pair of legs with the free joint subfusiform in shape, inner
apical seta short, spiniform, outer one 3 times as long.

Colour not yet ascertained.

Length of adult female 1.75 mm.

Male unknown.

Remarks.—This new species is readily recognised by the broadly
expanded anterior division of the body, the comparatively short caudal rami,
and the very powerful structure of the posterior antenne. In size it is, next
to H. maxima (Thompson), the largest of the northern species.

Occurrence.—Only a single female specimen of this form has hitherto
come under my notice. It was taken, several years ago, in the inner part of
the Stavanger Fjord, at Hjelmeland, from a depth of about 50 fathoms, among
dredged material.

95. Hermannella parva, Scott.
(Pl. XCIX).

Hermannella parva, Norman & Scott, Crustacea of Devon and Cornwall, p. 199, Pl. XIII, fig. 15;
Pl. XV, figs. 7—10; Pl. XVI, fig. 12; Pl. XIX, fig. 5.

Specific Characters,—Female. Body far less robust than in the pre-
ceding species, with the anterior division regularly oval in outline, greatest
width not nearly attaining half the length of the body and occurring in the
middle. Cephalic segment rather large and somewhat applanated, exhibiting
behind a well-marked transverse suture, front narrowly rounded. Epimeral
plates of the 3 succeeding segments obtusely rounded. Last trunkal segment
very small. Tail not fully attaining half the length of the anterior division
and attenuated behind; genital segment obpyriform in shape and scarcely longer
than the 3 succeeding segments combined. Caudal rami rather narrow, sub-
linear in form, and scarcely at all divergent, exceeding in length the 2 preced-

bia

ing segments combined; seta of outer edge attached near the middle; apical
sete rather unequal in length, the 2 middle ones being much longer than the
other 2, which are rather small. Anterior antenne shorter than the cephalon
and of a similar structure to that in the preceding species. Posterior antenne
however rather unlike, being far less robust and imperfectly prehensile; basal
joint not at all expanded; 2nd much the largest and angular at the end behind;
ord joint very short and armed at the end anteriorly with an unguiform spine
accompanied in front by 2 short sete; last joint well developed and carrying
at the tip 3 subequal, almost setiform claws, behind which 3 sete are attached.
Maxille with the masticatory lappet securiform in shape and almost nacked
outside; palp with one lateral and 2 apical sete. Anterior maxillipeds with
the terminal process much curved and clothed outside with delicate spinules.
Posterior maxillipeds well developed; propodal joint scarcely smaller than the
basal one, and armed inside, about in the middle, with a ciliated anteriorly-
curving spine; dactylar joint unguiform and having at the base a similar
spine to that of the propodal joint accompanied by a short seta. Natatory
legs comparatively more slender than in the preceding species; inner ramus
of 4th pair somewhat shorter and much narrower than the outer, terminal
joint with the inner edge quite smooth, outer edge exhibiting about in the
middle a well-marked ledge, apex with 2 very unequal spines flanked on each
side by a somewhat projecting corner. Last pair of legs with the free joint
exceedingly small and slightly produced at the end outside; both apical sete
very short. Ovisacs of moderate size, oblong oval in form, and slightly
divergent.

Colour pale yellow, with an orange tinge.

Length of adult female 0.73 mm.

Male unknown.

Remarks.—This form was described and figured by Scott in the above-
quoted treatise from a solitary female specimen. As observed by that author,
it somewhat resembles, in the general form of the body, Pseudanthessius
gracilis Claus. It is however of far inferior size and, one closer examination,
differs materially in the structure of the several appendages, agreeing in this
respect with the other species of the present genus.

Occurrence.—I have met with this form occasionally both of the west
and south coasts of Norway in moderate depths. All the specimens obtained
were of the female sex.

Distribution.—British Isles (Scott),

178

96. Hermannella prehensilis, G. O. Sars, n. sp.
(Pll Cc):

Specific Characters.—Female. Body rather slender, resembling some-
what in shape that of 7. parva, though having the anterior division less
expanded, with the greatest width in front of the middle. Last segment of
trunk rather narrow and exhibiting on each side, inside the insertion of the
free joint of last pair of legs, a small dentiform projection. Tail about half
the length of the anterior division; genital segment somewhat fusiform in
shape, being pronouncedly dilated in the middle, and shorter than the 3 suc-
ceeding segments combined; anal segment nearly twice as large as the pre-
ceding one. Caudal rami about the length of the last 2 segments combined
and slightly divergent; seta of outer edge attached in the middle; apical sete
nearly as in /7. parva. Anterior antenne rather slender, equalling about the
cephalon in length. Posterior antenne much shorter, but very strongly built
and pronouncedly prehensile; the first 2 joints rather thick and muscular; 3rd
joint very movably articulated to the 2nd and armed at the end anteriorly
with an exceedingly strong hooked claw; last joint small, without any claws,
but clothed with a number of thin curved sete. Maxille with the masticatory
lappet securiform and very finely denticulated along the outer edge; palp with
one lateral and 3 apical sete. Anterior maxillipeds about as in H. parva.
Posterior maxillipeds comparatively smaller, with the dactylar joint conical in
form and provided with a single small spinule inside. Natatory legs resembling
in structure those in H. parva, though having the inner ramus comparatively
shorter and stouter; that of 4th pair somewhat smaller than the outer, with
the terminal joint broader than in H. parva, and carrying 5 spines, one on the
outer edge, 2 on the inner, and 2 on the tip. Last pair of legs with the free
joint narrow cylindrical in form and having the 2 apical sete well developed.

Colour not yet ascertained.

Length of adult female 1.40 mm.

Male unknown.

Remarks.—This new species is especially distinguished by the peculiar
structure and pronouncedly prehensile character of the posterior antenne.
Otherwise it agrees pretty well with the other species of the present genus.

Oecurrence.—Only a single female specimen of this form has hitherto
come under my notice. It was taken, many years ago, at Skjerjehavn, outside
the Sogn Fjord from a depth of about 20 fathoms.

oe

97. Hermannella finmarchica, Scott.
(Pl. Cl).

Hermannella (2) finmarchica, Scott, Ann. Mag. Nat. Hist. Ser. 7, Vol. XI, p. 28, Pl. IV,
figs. 14—19.

Specific Characters—Female. Body comparatively slender, with the
anterior division oblong oval in outline, greatest width only sligtly exceeding
half the length and occurring somewhat in front of the middle. Cephalic
segment of moderate size and exhibiting behind a well-marked transverse
suture defining the cephalon from the Ist pedigerous segment, frontal margin
narrowly rounded. Last segment of trunk rather broad and, as in /7. prehen-
silis, exhibiting on each side, just behind the insertion of the free joint of
last pair of legs, a well-marked dentiform projection. Tail scarcely attaining
half the length of the anterior division; genital segment comparatively large,
exceeding in length the remaining 3 segments combined, and having the
anterior part rather dilated and sharply defined from the short cylindrical
posterior part. Caudal rami of moderate length, being about as long as the
last 2 segments combined, and slightly divergent; seta of outer edge attached
somewhat dorsally at about the hind third part of the ramus; the 2 middle
apical sete rather slender and elongated. Anterior antenna scarcely as long
as the cephalon, and having the first 2 joints comparatively broader than in
the preceding species. Posterior antenne resembling in structure those in
H. parva, being rather feeble and imperfectly prehensile, with the apical claws
slender, setiform. Maxille with the masticatory lappet securiform and finely
crenulated outside; palp with 1 lateral and 2 apical sete. Anterior maxillipeds
of normal structure. Posterior maxillipeds comparatively short and stout, pro-
podal joint conspicuously dilated in the middle and provided with 2 small
spinules; dactylar joint short, conical in form. Natatory legs comparatively
strongly built, with both rami well developed in all the pairs and about equal
in size, all the spines pronouncedly dagger-shaped; inner ramus of Ist pair, as
usual, with a single such spine, that of 2nd pair with 3, that of 3rd pair with
4, and that of 4th pair with 5 spines, all on the terminal joint. Last pair of
legs with the free joint of moderate size, sub-cylindrical in shape, and slightly
produced at the hind distal corner, apical sete well developed, the inner one
the longer. Ovisacs rather narrow and somewhat irregular in form.

Male, as usual, much smaller than female, and easily recognisable by
the greatly tumefied genital segment. Posterior maxillipeds with the propodos
somewhat contracted distally, dactylus long and slender, abruptly bent at the base.

180

Colour of female light yellow.

Length of adult female 1.30 mm., of male 0.90 mm.

Remarks.—Though the description and figures of this form given by
Scott are rather imperfect owing to the bad condition of the specimens ex-
amined by him, I cannot doubt that the above-described form is the same.
Scott had some doubt about its right position within the genus Hermannella,
and indeed in some points it differs conspicuously from the typical species
H. rostrata Canu, especially as regards the structure of the 4th pair of legs,
the inner ramus of which is much fuller developed than in that species. But
otherwise I find that it agrees fairly well with the other species here described.

Oceurrence.—| have met with this form occasionally both off the west
and south coasts of Norway in moderate depths. The specimens examined
by Scott were collected by Canon Norman in Buge Fjord, East Finmark. It
thus appears that this form is destributed along the whole Norwegian coast.
Out of Norway, however, it has not yet been recorded.

98. Hermannella tenuicaudis, G. O. Sars, n. sp.
(Pl. Cll).

Specific Characters.—Female. Body rather slender, with the anterior
division regularly oblong oval in outline, greatest width scarcely exceeding
half the length, and occurring about in the middle. Cephalic segment about
twice as long as the 3 succeeding segments combined, and exhibiting behind
a well-marked transversal suture, frontal margin narrowly rounded. Last trunkal
segment, as in the 2 preceding species, exhibiting on each side, behind the
insertion of the free joint of last pair of legs, a dentiform projection. Tail
very slender and attenuated, considerably exceeding half the length of the
anterior division; genital segment about the length of the 3 succeeding seg-
ments combined and considerably dilated in the middle. Caudal rami long
and narrow, fully equalling half the length of the remaining part of the tail,
and slightly divergent; seta of outer edge placed about in the middle and
somewhat dorsally; apical sete comparatively less elongated than in H7. fin-
marchica. Anterior antenne more slender, equalling in length the cephalon.
Posterior antenne very like those in the said species, though having the apical
claws still more slender. Maxille with the masticatory lappet rather large and
finely serrate along the outer edge, the proximal serrations rather coarse; palp
with 1 lateral and 3 apical sete. Anterior maxillipeds with the terminal process
less curved than in H. finmarchica and having the proximal spinule much

181

stronger than the others, lateral spine likewise with a coarse spinule near the
base followed by 3 much smaller ones. Posterior maxillipeds resembling in
shape those in the said species, though having the dactylar joint more pro-
duced. Natatory legs almost exactly as in 7. finmarchica. Last pair of legs
likewise rather similar, the free joint being cylindrical in form, with 2 very
unequal apical sete.

Body pellucid, of a whitish grey colour, with dark blue translucent
intestine.

Length of adult female 1.20 mm.

Male unknown.

Remarks.—This form is closely allied to 7. finmarchica, but at once
distinguished by the much longer and narrower caudal rami, reminding in
this respect on Pseudanthessius Thorelli Brady.

Occurrence.—Only a single female specimen of this form has hitherto
come under my notice. It was taken, many years ago, off the west coast ol -
Norway, the exact locality not having been noted, and a coloured drawing was
at that time made from the specimen, when still alive.

Gen. 43. Pseudomolgus, G. O. Sars 1916.

Generic Characters——General form of body resembling that in the
preceding genus, the anterior division being more or less expanded, the
posterior slender and attenuated. Cephalon well defined from the Ist pedige-
rous segment and produced in front below to an obtuse incurved rostrum.
Anterior antenne slender and generally composed of 7 articulations clothed
with comparatively short sete. Posterior antenne unusually short and stout,
with the outer joints impertectly separated, apical claws exceedingly strong,
hooked and distinctly biarticulate. Maxille with the masticatory part appar-
ently bifid, an appendicular lappet being inserted inside the principal one
and, like the latter, produced to a slender incurved lash; principal lappet
coarsely denticulate along the outer edge; palp small, lamellar. Anterior
maxillipeds with the terminal process short and armed with a limited number
of subequal spinules. Posterior maxillipeds in female imperfectly developed,
sub-lamellar, and apparently quite immobile; those in male, as usual, well
developed, prehensile. Natatory legs with the rami rather broad and subequal

24.—Crustacea.

_ 182

in size; inner ramus of 4th pair resembling that in the preceding pairs. Last
pair of legs more fully developed than in the preceding genera, the free joint
being rather produced, and armed with one lateral and 2 apical spines having
between them a slender bristle.

Remarks.—The type of this genus, recently established by the present
author, is Lichomolgus arenicola Brady, which, as shown by T. Scott, differs
in several points very conspicuously from Thorell’s genus. Scott referred this
form provisionally to the genus Hermannella of Canu, apparently owing to
the distinctly 3-articulate inner ramus of the 4th pair of legs. It cannot how-
ever in my opinion be referred to that genus, as it differs in some very im-
portant points, thus in the structure of the posterior antenne, the maxille, the
posterior maxillipeds in the female, and finally in the form and armature of
the last pair of legs. The typical species has not yet been observed by me;
but 2 nearly allied species will be described below.

99. Pseudomolgus leptostylis, G. O. Sars.
(PI. Cll).

Pseudomolgus leptostylis, G. O. Sars, Bulletin de l'Institut océanographique de Monaco
No. 3238, 1916, p. 51, Pl. III.

Specific Characters.—Female. Body rather slender, but with the
anterior division conspicuously more expanded than in the type species and
broadly oval in outline, greatest width exceeding half the length and occur-
ring in front of the middle. Last truncal segment rather narrow and without
any lateral projections. Tail very slender and narrow, considerably exceeding
half the length of the anterior division; genital segment not very large and
only slightly dilated in the middle; anal segment nearly as long as the 2
preceding segments combined. Caudal rami much more produced than in the
type species and very narrow, attaining almost half the length of the remaining
part of the tail; seta of outer edge attached about in the middle; apical sete
not much elongated. Anterior antenne moderately slender, not fully attaining
the length of the cephalon, and composed of 7 well defined joints, the 2nd
of which is the longest. Posterior antennae much shorter than the anterior,
but very strongly built and of nearly equal width throughout, last 2 joints
completely fused together, apical claws 4 in number of about equal length,
the hindmost one, however, conspicuously narrower than the others. Maxille
with the principal masticatory lappet coarsely denticulated along the outer
edge, the 2 proximal denticles being much stronger than the others; palp

sae

forming a somewhat irregular short lamella carrying 2 small sete, one outside
and one at the tip, inner edge with an angular projection in the middle.
Anterior maxillipeds with the termimal process divided into 5 slender subequal
spinules. Posterior maxillipeds without any armature whatever, each forming
a simple somewhat lamellar stem terminating in a minute point. Natatory
legs with the Ist joint of the outer ramus distinctly denticulated outside;
terminal joint of inner ramus in Ist pair with one, in 2nd pair with 3, and
in the last 2 pairs with 4 spines; all the spines distinctly dagger-shaped. Last
pair of legs with the free joint narrow oblong in form, edges partly ciliated,
marginal spines rather slender, that of the outer edge attached at about the
posterior 4th part of the joint.

Male, as usual, of smaller size than female, and having the genital
segment considerably dilated. Posterior maxillipeds powerfully developed, with
the propodos coarsely denticulated along the whole inner edge, dactylus long
and curved.

Colour not yet ascertained.

Length of the female here described about 2 mm.; that of male 1.50 mm.

Remarks.—This species has recently been briefly mentioned and figured
by the present author in the above-quoted journal from a female specimen
procured during the Monaco Expedition. It is closely allied to the type species,
P. arenicola (Brady), but easily distinguished by the comparatively broader
and more expanded anterior division of the body, and more particularly by
the much more produced caudal rami. The structure of the several appen-
dages seems .to agree very closely with that in the type species, except that
the anterior antenne are distinctly 7-articulate, whereas these antenne in
P. arcnicola, both according to Brady and Scott, are only composed of 6 joints.

Occurrence.—A solitary adult female specimen of this form (that here
figured) was taken, several years ago, in the inner part of the Trondhjem Fjord,
at Vennes, from the considerable depth of 100—150 fathoms, and recently
some few young female specimens and an adult male were picked up from
the bottom-residue of a large collecting bottle containing various animals col-
lected by Mr. Kjer in the Christiania Fjord, near Drobak.

Distribution.—Otf the Amsterdam island, Spitsbergen (Monaco expedition).

184

100. Pseudomolgus dilatatus, G. O. Sars, n. sp.
(PI. CIV).

Specific Characters.—Female. Body far less slender than in the pre-
ceding species, with the anterior division considerably expanded and rounded
oval in outline, greatest width equalling half the length of the body (without
the caudal rami). Cephalic segment much broader than it is long, and having
the edges quite evenly arcuate throughout. Last trunkal segment comparatively
broader than in the preceding species. Tail only slightly exceeding half the
length of the anterior division; genital segment of moderate size and slightly
dilated in front; anal segment but little longer than the preceding one. Caudal
rami rather narrow and produced, though not nearly attaining half the length
of the remaining part of the tail; seta of outer edge attached about in the
middle and somewhat dorsally; apical sete about as in the preceding species.
Anterior antenne rather slender, exceeding somewhat the length of the cephalon
and, as in the preceding species, composed of 7 well defined joints. Posterior
antenne of a still more compact structure than in the preceding species, being
scarceiy more than half as long as the anterior ones, but very thick; apical claws
3 in number, the hindmost one rather thin, almost setiform, the other 2 very
large with the distal part strongly hooked. Oral parts nearly agreeing in
structure with those in the preceding species. Legs also very similar; those
of last pair however comparatively smaller, with the marginal spines less slender.

Colour not yet ascertained.

Length of the specimen examined 1.40 mm.

Male unknown.

Remarks.—The above-described species is evidently congeneric with
the preceding one, though easily distinguishable by the much more robust
form of the body, as also by the structure of the posterior antenne. It is
moreover rather inferior in size.

Occurrence.—A single female specimen of this form was taken, many
years ago, in the Romsdal Fjord, near Molde, from a depth of about 100
fathoms.

Gen. 44. Rhinomolgus, G. O. Sars, n.

Generic Characters.—Body cyclopoid in shape, with the anterior division
moderately expanded. Cephalon only faintly separated from the Ist trunkal
segment, and provided beneath the front with a peculiar mobile rostral lamella.

mis

Tail with the genital segment in female scarcely subdivided. Caudal rami
sub-lamellar, with 2 successive sete on the outer edge and 3 onthe tip. An-
terior antennze composed in female of 7 joints, the first 2 of which are much
larger than the others and clothed with numerous strong sete; outer joints in
male coalesced. Posterior antenne much elongated and distinctly prehensile,
being armed at the tip with a short uncinate claw. Anterior lip deeply incised
in the middle. Maxille with a slender appendicular masticatory lappet inside
the principal one; the latter securiform in shape and rather expanded at the
base, its outer edge coarsely serrated and divided proximally into 2 unequal
lobules, one of which is distinctly denticulaled; palp unusually large and in-
curved, resembling in structure that in the Clausidiide. Anterior maxillipeds
with the basal part very large and massive, terminal part produced into a
straight digitiform process denticulated at the tip, and having inside a densely
spinulose seta. Posterior maxillipeds, as usual, very different in the 2 sexes,
in female conically tapered, with the dactylar joint small and tipped by a short
uncinate claw, in male very large and distinctly prehensile, dactylus long and
slender. Natatory legs strongly built, with both rami 3-articulate in all the
pairs. Last pair of legs biarticulate, proximal joint small and less perfectly
separated from the segment, distal joint comparatively large, foliaceous, and
extending laterally, being armed in a similar manner to that in the preceding
genus.

Remarks—This is a very distinct genus, exhibiting several aberrant
characters, some of which seem to point to the Clausidiide. According to
the prehensile nature of the posterior antenne and the structure of the masti-
catory part of the maxille, it ought however unquestionably to be included
in the present family. One of the most perplexing peculiarities is perhaps the
remarkable mobile rostral lamella, from which indeed the generic name here
proposed has been derived. The genus comprises as yet only a single species,
to be described below.

101. Rhinomolgus anomalus, G. O. Sars, n. sp.
(PI. CV & CVI).

Specific Characters.—Female. Body not particularly slender, with the
anterior division oval fusiform in outline, greatest width about equalling 2/3 of
the length and occurring a little in front of the middle. Cephalic segment
large, and exhibiting behind a rather slight transverse suture defining the
cephalon from the Ist pedigerous segment; front narrowly rounded. Rostral

lamella pronouncedly spatulate in form, being contracted at the base and
gradually widening towards the extremity, which is broadly truncated. Lateral
lobes of the 3 succeeding segments rounded of the end. Last truncal segment
rather narrow. Tail exceeding half the length of the anterior division; genital
segment about as long as the 3 succeeding segments combined, and some-
what dilated in the middle; anal segment scarcely larger than the preceding
one. Caudal rami somewhat lamellar and oblong oval in form, exceeding in
length the anal segment, inner edge finely ciliated, outer edge with 2 suc-
cessive sete, the distal one apparently answering to the outer apical seta
in other forms, the somewhat narrowed extremity carrying 3 unequal sete
and a small dorsal bristle extending outwards. Eye wholly absent. Anterior
antenne shorter than the cephalon, and somewhat abruptly bent near the
middle, being composed of 7 well defined joints, the 2nd of which is much
the largest and densely clothed with unusually long and coarse, finely an-
nulated sete, the 5 outer joints much narrower than the first 2. Posterior
antenne exceeding in length the anterior and nearly nacked, being composed
of 5 well defined joints, the first of which is very short, the 2nd much the
largest, the 3rd about half as long and equal to the combined length of
the outer 2 joints; terminal joint armed on the tip with a comparatively short
uncinate claw accompanied by a small bristle, and having moreover 2 unequal
sete attached to a distinct ledge at some distance from the tip behind.
Natatory legs with the inner ramus a little longer than the outer, its terminal
joint comparatively large, fully as long as the other 2 combined, and ex-
hibiting a somewhat different armature in the several pairs, that of Ist pair
having one spine outside the tip, that of 2nd pair 3, that of 3rd pair 4, and
that of 4th pair 5 spines. Last pair of legs with the proximal joint rather
small and carrying outside the usual slender bristle; distal joint oblong
oval in form and finely ciliated on the proximal part of the inner edge,
being moreover provided with 3 slender marginal spines, one somewhat
beyond the middle of the outer edge, the other 2 on the obtusely rounded
extremity; between the latter a small bristle is attached. Ovisacs not very
large, oval in form, and closely appressed to the sides of the tail.

Male somewhat smaller than female, and having the anterior division
of the body less broad. Genital segment considerably tumefied and terminating
on each side in a triangular lappet clothed with 2 sete and a small denticle.
Anterior antenne with 2 well-defined recurved estethasks, the one attached to
the 2nd, the other to the 4th joint; the 3 outer joints wholly coalesced.
Posterior maxillipeds very powerfully developed, propodos with the outer edge

sub-angular in the middle, inner edge straight and clothed with a row of
slender spinules; dactylus very long and provided at the base inside with a
slender spine.

Colour of female whitish grey, with translucent pale yellow ovarial tubes.

Length of adult female 2.45 mm.; of male 2.20 mm.

-Remarks.—The above-described form is easily distinguished from any
of the other Lichomolgide, both as to the general form of the body and to
the structure of the several appendages. The remarkable rostral lamella
attached beneath the frontal part of the head, between the insertions of the
anterior antenne, is more generally extended downwards, and accordingly is
most conspicuous in the lateral or ventral aspects of the animal. As it how-
ever is very mobile, it may in some cases be protracted, so as to be
visible also in the dorsal view of the animal, projecting in front with its
broadly truncated extremity, as shown by the figures here given.

Occurrence.—A considerable number of specimens of this peculiar
Copepod were picked up from the dredged material obtained by a single
catch made in the outer part of the Trondhjem Fjord, about midway between
Bejan and the opposite border of the Fjord, the depth ranging from 100 to
150 fathoms. The material conta‘ned various deep-water animals, of which a
species of Antedon, A. Sarsi, was by far the most abundant. Though I am
much disposed to believe that thc present Copepod is a parasit of the said
Crinoid, I am unable to state this with full certainty, as none of the speci-
mens were found in immediate conn2xion with their supposed hosts.

Gen. 45. Sabelliphilus, M. Sars, 1862.

Generic Characiers—Form of body rather different from that in the
other genera of the present family, being very narrow, with the anterior division
only slightly dilated. Cephalon faintly defined from the lst trunkal segment,
and provided below the front with a strongly chitinised, immobile rostral plate
extending backwards and deeply bifurcate at the end. Tail composed of the
usual number of segments. Anterior antenne 7-articulate, with the first 2 joints
much larger than the others and lamellarly expanded. Posterior antenne
exceedingly powerful and armed at the end with very strong uncinated claws,

188

as also with a row of coarse spines inside the 2nd joint. Oral parts on the
whole of normal structure. Natatory legs comparatively slender, with both
rami 3-articulate; inner ramus of 4th pair with the number of sete reduced.
Last pair of legs very small, bisetose.

Remarks.—This genus was established by my late father as early as
the year 1862, to include a peculiar Copepod found by him parasitic on the
gills of a species of Sabella. It ought undoubtedly to be included in the
family Lichomolgidw, as here defined, in spite of the aberrant form of the
body and the likewise somewhat aberrant structure of the 2 pairs of antenne.
The genus comprises as yet only a single species, to be described below.

102. Sabelliphilus elongatus, M. Sars.
(PI. CVI).

Sabelliphilus elongatus, M. Sars, Beskrivelse af 4 nye parasitiske Copepoder. Forh. Christiania
Vid. Selskab f. 1861, p. 139.

Syn: Sabelliphilus Sarsii, Claparede.
% - Leuckartii, Kossman.
Lichomolgus sabellz, Thompson.

Specific Characters.—Female. Body very slender and elongated, with
the anterior division narrow oblong in outline, greatest width only slightly
exceeding 1/3 of the length. Cephalic segment nearly twice as long as the 3
succeeding segments combined and obtusely truncated in front, exhibiting
behind a rather faintly marked transverse suture defining the cephalon from
the Ist pedigerous segment; rostral plate of moderate size and closely ap-
pressed to the ventral face, projecting at the end into 2 strong spiniform pro-
cesses. Lateral lobes of the 3 succeeding segments obtusely rounded. Last
trunkal segment very small. Tail scarcely attaining half the length of the
anterior division; genital segment of moderate size and considerably tumefied
in its anterior part; anal segment longer than the preceding one. Caudal
rami rather narrow, exceeding somewhat the anal segment in length, and scar-
cely divergent; seta of outer edge attached near the middle; apical sete slender,
the inner median one attaining the length of the tail. Anterior antenne about
half the length of the cephalon and clothed with comparatively short sete;
the first 2 joints much larger than the others and pronouncedly lamellar; 3rd
joint very small; the remaining 4 joints gradually diminishing in size. Posterior
antenne unusually strongly built, 4-articulate, the first 2 joints very massive
and forming with each other a geniculate bend; 2nd joint exhibiting inside a
longitudinal crest divided into 5 very strong teeth; 3rd joint armed at the end

ESO»
anteriorly with a strongly uncinate claw; terminal joint with 3 similar claws
accompanied by a number of curved seta. Maxille with the masticatory
lappet simple, securiform, and exserted to a slender point, outer edge coarsely
serrate; palp comparatively narrow, with one lateral and 3 short apical sete.
Anterior maxillipeds with the basal part rather broad and provided outside
with a densely serrated crest, terminal part exserted to a narrow incurved lash
armed outside with 4 strong spinules and having inside at the base the usual
appendicular spine. Posterior maxillipeds of moderate size, with the propodal
joint about equal in size to the basal one; dactylar joint forming a strongly
uncinate claw, with a small appendicular spine inside. Natatory legs of com-
paratively feeble structure, with the rami rather narrow and nearly equal-sized
in the 3 anterior pairs; inner ramus of 4th pair somewhat smaller, with the
terminal joint narrow oblong in form and only provided with 2 spines at the
end. Last pair of legs with the free joint short cylindrical in form, apical sete
rather small, the outer one the longer. Ovisacs very narrow and elongated,
cylindrical in form.

; Body in female of a whitish grey colour, with dark fuscous translucent
ovarial tubes. Eye well marked, of bright red colour.

Length of adult female 1.65 mm.

Remarks.—The present form, as above mentioned, was briefly described
by my late father under the above name, and has subsequently been observed
by several other authors, though the specific identity was not recognised by
them. I regard it as beyond doubt that the form recorded by Claparede as
S. Sarsii is the very same species, and this seems also to be the case with
S. Leukartii of Kossman and with Lichomolgus sabellcee of Thompson.

Occurrence.—My late father found this form attached to the gills of
Sabella Sarsi captured off the west coast of Norway. I have myself met with
this Copepod in 2 widely distant localities, viz., at Kvalé6, on the Nordland
coast, and at Risdér, south coast of Norway. In both localities only a single
female specimen was obtained among dredged material and detached from
its host.

Distribution.—British Isles (Thompson), coast of France (Canu), Medi-
terranean (Claparede, Della Valle).

25.—Crustacea

190

Fam. 12. Onceide.

General Characters.—Body of rather different shape in the different
genera, but with the anterior and posterior divisions always well defined, the
latter generally rather slender and attenuated. Eye imperfectly developed or
quite absent. Anterior antenne not much elongated, with the number of joints
more or less reduced. Posterior antenne imperfectly prehensile. Maxillz and
anterior maxillipeds comparatively small. Posterior maxillipeds, as a rule,
powerfully developed in both sexes, terminating in a clawed hand. Natatory
legs with both rami 3-articulate, the inner one generally more slender than
the outer. Last pair of legs small, uniarticulate.

Remarks.—This family was originally established by Giesbrecht to
comprise 5 different genera, viz., Oncaea, Conca, Lubbockia, Pachysoma and
Ratania. The last named genus was however subsequently removed by that
author and referred to the siphonostomous Cyclopoida (Asterocheride). A
new genus referable to the present family, Pseudolubbockia, has more recently
been added by the present author, so that the family still comprises 5 genera.
The most aberrant of these genera is unquestionably the genus Pachysoma
of Claus, the systematic position of which seems to me to be rather question-
able. All the forms comprised within the present family lead a true pelagic
existence; but it is very probable that, like the Lichomolgide, they are in
reality semiparasitic in habits, though it has not yet been stated which pelagic
animals are at time infested by them. Of the above-named genera only one
is as yet represented in the Fauna of Norway.

Gen. 46. Onceea, Philippi, 1843.

Syn: Antaria, Dana.

Generic Characters.—Body cyclopoid in shape, with the anterior division
more or less dilated and strongly vaulted above. Cephalon distinctly defined
from the Ist trunkal segment, and having below the front an obtuse incurved
rostral prominence. The 3 succeeding segments gradually diminishing in size,
and having the epimeral parts rounded and but little prominent. Last trunkal
segment very small, though distinctly defined. Tail attenuated and composed
in female of 4, in male of 5 segments, the Ist of which (the genital segment)

‘991

is much the largest. Candal rami comparatively small, with the normal number
of sete. Eye wholly absent. Anterior antenne of moderate length, 6-articulate,
3rd joint much the largest, the outer 3 joints forming together a well defined
terminal part very movably articulated to the preceding joint and clothed at
the end with long diverging sete. Posterior antenne smaller than the anterior
and more or less strongly curved, being composed of only 3 joints, the last
of which is provided at the end with long rigid sete curving anteriorly. Max-
ille armed at the incurved extremity with 2 short movable claw-like spines;
palp sub-clavate in form, with a limited number of small marginal sete. An-
terior maxillipeds biarticulate, distal joint carrying on the end 2 digitiform
appendages coarsely spinulose on the inner edge. Posterior maxillipeds power-
fully developed in both sexes and distinctly prehensile, propodos more or less
dilated, dactylus slender and very mobile, especially in male. Natatory legs
with the outer ramus more strongly built than the inner and armed outside
and at the tip with coarse dagger-like spines, inner ramus with the terminal
joint much produced, especially in the posterior pairs, assuming in the latter a
narrow linear form. Last pair of legs small, bisetose. Two ovisacs present in
female, attached somewhat dorsally, so as partly to cover the tail.

Remarks.—This genus was established as early as the year 1843 by
Philippi, to include a mediterranean species (O. venusta). The genus Antaria
of Dana is identical with Philippi’s genus. No less than 10 different species
are recorded by Giesbrecht in his great work. They all are very nearly
related, and in some cases not easy to distinguish without a very close ex-
amination. The chief distinguishing characters refer to the relative size of the
genital segment in the female, the length of the caudal rami, and partly also
the mutual length of the outermost and innermost apical-seta of the tail. Two
Norwegian species of this genus will be described below.

103. Once@a borealis, G. O. Sars, n. sp.
(PI. CVIII).

Syn: Oncea conifera, G, O. Sars (not Giesbrecht).

Specific Characters.—Female. Body comparatively slender, with the
anterior division oblong fusiform in outline, greatest width scarcely attaining
half the length, and occurring about in the middle, 2nd trunkal segment, as
in O. conifera, raised dorsally in the form of an hump-like prominence. Tail
about half the length of the anterior division; genital segment scarcely longer
than the remaining part of the iail, and gradually somewhat narrowed behind,

12

anal segment shorter than the 2 preceding segments combined. Caudal rami
very small, being much shorter than the anal segment, and scarcely more than
twice as long as they are broad; seta of outer edge attached a little in front
of the middle; innermost apical seta slightly exceeding the outermost in length.
Antenne and oral parts on the whole resembling in structure those in O. coni-
fera. Posterior maxillipeds, however, somewhat less strongly developed, with
the propodos oblong oval in form; dactylus somewhat shorter than the pro-
podos and finely denticulated along the inner edge. Natatory legs with the
rami comparatively more slender than in O, conifera, and the spines of the
outer ramus less strong. Last pair of legs with the free joint much smaller
than in that species, not cylindrical, but rounded oval in form. Ovisacs of
moderate size, extending about to the end of the anal segment, and oval
in form.

Male much smaller than female, with the anterior division of the
body narrower and wanting the dorsal hump. Tail comparatively shorter, with
the genital segment very large and tumid. Anterior antenne with the joints
of the terminal part imperfectly separated. Posterior maxillipeds resembling in
structure those in female, but of somewhat larger size, with the dactylus longer
and quite smooth.

Body in both sexes, pellucid, with a fainte yellow or orange tinge.

Length of adult female scarcely exceeding 0.70 mm.; that of male
0.40 mm.

Remarks.—The above described species has been previously identified
by the present author with O. conifera Giesbrecht, which it ressembles in the
presence on the 2nd trunkal segment in the female of a hump-like dorsal
prominence. Having however now had an opportunity of examining Gies-
brecht’s species, I find it to differ in some points so markedly that I am led
to the conclusion, that it is specifically distinct from the form here treated of.
I have recently examined another form from the Malayan Archipelago, the
female of which has a quite similar dorsal hump, and which on this cause
has been identified by Clewe with O. conifera; but which, on a closer ex-
amination, has turned out to be a very distinct species, different both from
that species and the one here described. The above-mentioned dorsal hump
cannot therefore be regarded as a character exclusive of O. conifera. The
latter is a much larger and more robust species than the one here treated of,
and moreover differs conspicuously in the relative size of the genital segment
in the female, as also in the much fuller development of the last pair of legs.

193

Occurrence.—I have met with this form occasionally in plankton both
of the west and south coasts of Norway, as also in the upper part of the
Christiania Fjord. Mr. Nordgaard has taken it in Oster Fjord, near Bergen.

Distribution.—Polar Sea, north of Siberia (Nansen’s Expedition), British
Isles (Farran).

104. Oncea similis, G. O. Sars, n. sp.
(PI. CIX, fig. 1).

Specific Characters.—Female. General form of body very similar to
that in the preceding species, though perhaps a little more slender. Anterior
division narrow fusiform in outline, with the dorsal face quite evenly vaulted,
no trace being found of the dorsal hump present in the preceding species.
Tail about half the length of the anterior division, and having the genital
segment rather large, nearly twice as long as the remaining part of the tail;
the 2 succeeding segments very short, and combined scarcely longer than the
anal segment. Caudal rami about the length of that segment and agreeing
in form and armature with those in the preceding species. Antenne and oral
parts also very similar, except that the maxillary palp is of somewhat simpler
structure, being only provided with 5 marginal sete. Natatory legs on the
whole agreeing in structure with those in the said species, though having the
spines of the outer ramus comparatively stronger and more coarsely denticulated.
Last pair of legs with the free joint still smaller than in O. borealis; apical
sete, however well developed.

Colour not yet ascertained.

Length of adult female 0.78 mm.

Male unknown.

Remarks.—The present form is closely allied to O. borealis, and may
indeed at the first sight be easily confounded with it. On a closer inspection
it is however at once distinguished by the absolute absence of the characteristic
dorsal hump, as also by the rather different mutual relation of the caudal
segments.

Occurrence.—A few female specimens of this form were found together
with O. borealis in a plankton-sample taken by Mr. Nordgaard in the Oster
Fjord, near Bergen, and kindly sent to me for examination.

aceon

Fam. 13. Coryceide.

General Characters.—Body not at all depressed, but more or less
pronouncedly club-shaped, with the anterior division well defined from the
posterior and obtusely truncated anteriorly. Front without any true rostral
prominence, but provided with 2 very large juxtaposed corneal lenses (con-
spicilla). 1st trunkal segment confluent with the cephalon, or only very slightly
defined from it. The 3 succeeding segments in some cases imperfectly separated
dorsally; lateral lobes af 3rd segment generally produced to acute lappets.
Last trunkal segment imperfectly developed. Tail with the segments reduced
in number, in some cases wholly confluent. Caudal rami more or less pro-
duced, styliform, with the apical sete partly spiniform and reduced in number.
Anterior antennze comparatively small; posterior ones very strong and pro-
nouncedly prehensile, terminating in a clawed hand, which is larger in male
than in female. Oral area placed far behind and somewhat prominent. Max-
ill and anterior maxillipeds very small and clawed at the extremity. Posterior
maxillipeds well developed in both sexes and distinctly prehensile. Natatory
legs with the inner ramus much smaller than the outer; that of 4th pair much
reduced or quite wanting. Last pair of legs absent in both sexes. |

Remarks.—This family is here taken in a more restricted sense than
done by Giesbrecht, who comprised within it also the genus Sapphirina and
allied genera. These, I believe, should more properly be removed to a sepa-
rate family, the Sapphirinide, as they differ very conspicuously both in the
general form of the body and in some of the structural details. In the restric-
tion here adopted the family as yet only comprises 2 nearly-allied genera,
viz., Coryceeus Dana and Corycella Farran. Only the first-named genus is
represented in the Fauna of Norway.

Gen. 47. Coryczeus, Dana, 1845.

Syn: Agetus, Kroyer.

Generic Characters.—Body more or less elongated, subclavate in form,
with the anterior division only slightly dilated. Cephalic segment very large,
and in most cases exhibiting behind, across the back, a fainte suture, indicating
the limit between the cephalon and the Ist trunkal segment; corneal lenses

eee
distinctly separated in the middle; pigmented ocular rodes far remote from the
corneal lenses and converging to a point placed about in the middle of the an-
terior division, near the ventral face; each provided at the distal end with a highly
refractive body.') 3rd trunkal segment produced on each side to an acute
posteriorly-pointing lappet; 4th segment much smaller than the preceding one,
and in some cases confluent with it dorsally. Tail composed in both sexes of
only 2 segments, which in some cases are imperfectly separated. Caudal rami
narrowly produced, with 2 unequal spiniform apical seta accompanied by a
slender sub-dorsal bristle. Anterior antenne short, 6-articulate. Posterior an-
tenne powerfully developed, especially in male, 3-articulate; middle joint rather
dilated; terminal joint very mobile and tipped with a slender claw. Maxille
armed at the extremity with a bifid movable claw, inside which a likewise
movable spiniform appendage coarsely pectinate on the outer edge is attached;
palp comparatively small, scale-like. Anterior maxillipeds short, with the termi-
nal part imperfectly defined from the basal one and exserted to a curved claw,
having moreover at the base inside 2 or 3 unequal pectinated sete. Posterior
maxillipeds distinctly 3-articulate, the last 2 joints forming together a clawed
hand more strongly developed in male than in female. The 3 anterior pairs
of natatory legs with both rami 3-articulate, the outer one much the larger
and rather produced, being armed outside and at the tip with strong denticulated
spines. 4th pair of legs much feebler in structure, with the inner ramus reduced
to a single small joint. Ovisacs in female attached dorsally and in some cases
confluent.

Remarks.—This genus was established by Dana as early as the year
1845, and is the type of the present family. The genus Agetus of Kréyer is
identical with Dana’s genus. It comprises a great number of species chiefly
occurring in southern latitudes. No less than 20 different species have been
enumerated by Giesbrecht in his great work; but some of these are more
properly referable to the nearly-related genus Corycella Farran. Off the Norwegian
coast only a single species has as yet been observed, to be described below.

1) | am however by no means convinced that the above-mentioned parts, as generally
opined, are in reality visual in significance, but should be much more inclined to suppose, that
they constitute a peculiarly modified photogenous apparatus for projecting condensed light forwards,
like the light-projectors of our automobiles. To settle this question, observations on living
specimens would be needed.

196

105. Corycaeus anglicus, Lubbock.
(PIMOS fipe 2 RRKGN))

Coryceus anglicus, Lubbock, Ann. & Mag. Nat. Hist. 2nd series, Vol. XX, p. 408, Pl. XI,
figs. 14—17.

Syn: Coryceus germanus, Leuckatt.

Specific Characters.— Female. Body moderately slender, with the anterior
division narrow oblong in outline, greatest width not nearly attaining half the
length and occurring somewhat in front of the middle. Cephalic segment very
large, occupying about half the length of the body, and exhibiting across the
back behind a rather slight suture limiting the cephalon from the Ist trunkal
segment; lower edges strongly bulging in front of the middle. Lateral lappets
of 3rd segment rather large, wing-like, and acuminate at the end, extending
about as far as the middle of the genital segment; 4th segment well defined,
and somewhat angular laterally. Tail slightly exceeding half the length of
the anterior division and having its 2 segments well defined, the proximal
one (genital segment) rather tumid and carinated below, the carina forming
in front of the middle a projecting angle; distal caudal segment about half as
long as the proximal one and evenly narrowed behind. Caudal rami rather
slender, being fully twice as long as the anal segment, and conspicuously
divergent; seta of outer edge very small and attached at a short distance from
the end, the outer corner of which is produced to a small dentiform projection;
inner apical seta about the length of the corresponding ramus and more than
twice as long as the outer. Anterior antenne with the joints not much dif-
ferent in size and clothed with slender diverging sete. Posterior antenne with
a long spiniform seta issuing from the end of the basal joint anteriorly; middle
joint large, oblong oval in form, and carrying inside the base a similar, but
much shorter seta, its anterior edge forming a thin lamella divided at the end
into 2 unequal dentiform projections, terminal joint armed at the base with 2
claw-like spines and carrying at the end a similar spine and a much stronger
curved claw. Posterior maxillipeds with the propodos not much dilated and
provided near the end with a short spine; dactylus about the length of the
propodos. Outer ramus of the 3 anterior pairs of legs rather strongly built,
with the terminal joint much the largest and armed with 4 spines, one on the
tip and 3 on the outer edge; inner ramus scarcely more than half as long and
much narrower, its terminal joint being provided in the lst pair with 5,
in the 2nd pair with 4, and in the 3rd pair with only 2 sete. 4th pair of
legs conspicuously smaller than the 3 preceding ones, outer ramus with no

197

spines on the middle joint and with only a single one on the terminal joint;
inner ramus represented by a small joint carrying 2 slender seta. Ovisacs
confluent to a single almost globular bag attached to the dorsal face of the
genital segment.

Male of about same size as female, and having the body more pro-
nouncedly club-shaped. Lateral lappets of 3rd trunkal segment comparatively
smaller. Tail with the genital segment considerably tumefied; anal segment
smaller than in female. Caudal rami scarcely at all divergent. Posterior
antenne still more strongly developed than in female, with the apical claw
much more produced. Posterior maxillipeds likewise more powerful, with the
propodos larger and the dactylus very long.

Body in both sexes highly pellucid, and in some places tinged with
a light reddish orange pigment.

Length of adult female about 1 mm.

Remarks.—This form was first described by Lubbock from specimens
captured at the west coast of England (Plymouth), and has subsequently also
been observed by several other authors, though its identity has not always
been recognised. Thus the C. germanus of Leuckart is unquestionably the
very same species. It is nearly allied to C. obtusus of Dana, but apparently
specifically distinct.

Occurrence.—I have met with this form occasionally off the west coast
of Norway, as also in the Christiania Fjord, at Drébak, among plankton taken
near the surface of the sea. It is, like the other species of this genus, a pro-
nouncedly pelagic animal, which has its true home in the open sea and only
quite accidentally is thrown by the currents nearer to the shores and into
the Fjords.

Distribution.—North Atlantic Ocean, off the British Isles (Lubbock &
Brady), Helgoland (Leuckart); coast of Bohuslén (Trybom).

Fam. 14. Ergasilide.

General Characters—Body in the juvenile state of the animal quite
cyclopoid in shape, becoming however in the adult female, after its affixion,
more or less deformed. Eye simple, of normal appearance. Anterior antenne
comparatively short, resembling in structure those in the Coryeeide. Posterior

26.—Crustacea.

198

antenne pronouncedly prehensile, terminating in a very movable claw, and
more strongly developed in female than in male. Oral parts, as in the Cory-
ceide, densely crowded on a protuberance of the ventral face, placed far
behind the insertion of the antenne. Maxille and anterior maxillipeds very
small and clawed at the extremity. Posterior maxillipeds wanting in female,
normally developed in male. Natatory legs comparatively feeble in structure,
with the rami more or less incurved. Last pair of legs small, but well defined,
uniarticulate. Ovisacs in female of very large size.

Remarks.—This family also is here taken in a more restricted sense
than done by most other authors. Thus I find it necessary to remove the
genus Bomolochus of Nordman, which is generally included in the present
family, but which seems to me to differ in many points so materially from
the other genera, that it scarcely can be associated with them. In the restriction
here adopted the family as yet only comprises 3 genera, viz., Ergasilus Nordman,
Ergasiloides G. O. Sars and Thersetina Norman (Thersites Pagenstecher). Only
the first-named genus is as yet stated to be represented in the fauna of Norway.

Gen. 48. Ergasilus, Nordman, 1832.

Generic Characters.—Body of adult female more or less pyriform in
shape, with the anterior part greatly tumefied and the segments not very
sharply marked off from each other; that of young female (before affixion)
and of male pronouncedly depressed and tapered behind, with all the segments
sharply defined. Tail comparatively short, and composed in female of 4, in
male of 5 segments. Anterior antenne 6-articulate and densely setiferous.
Posterior antenne in female exceedingly powerful, 3-articulate, terminal joint
together with its apical claw forming a very strong and movable dactylus
admitting of being bent against the preceding joint; those in male much
smaller, but of a similar structure. Maxilla armed at the extremity with a
movable claw-like spine accompanied by a short seta, and having moreover a
somewhat similar spine outside at some distance from the tip; palp small,
lamelliform. Anterior maxillipeds terminating in a single claw-like spine densely
hairy on the edges. Posterior maxillipeds wholly. absent in female, but well
developed in male and terminating in a slender clawed hand. Natatory legs
with the rami comparatively short and 3-articulate, except the outer ramus of

199

Ath pair, which is only composed of 2 joints. Last pair of legs with the free
joint well defined, bisetose.

Remarks.—This genus, the type of the present family, was established
by Nordman as early as the year 1832, to include a peculiar parasite (E.
Sieboldi) found by him on the gills of various fresh-water fishes. Another
species apparently referable to this genus was subsequently recorded by Van
Beneden under the name of £E. manus. Only the type species is as yet
represented in the fauna of Norway.

106. Ergasilus Sieboldi, Nordman.
(Pl. CXI).

Ergasilus Sieboldi, Nordman, Mikrographische Beitrage zur Naturgeschichte wirbelloser Thiere,
Heft 2.

Specific Characters.—Young female (before affixion). Body moderately
slender and gradually tapered behind, with the anterior division oblong in
outline, greatest width not nearly attaining half the length and occurring in
front of the middle. Cephalon well defined from the trunk and almost penta-
gonal in form, the frontal part being somewhat produced and narrowly rounded.
Trunkal segments defined from each other by deep lateral incisions and gradu-
ally diminishing in size, epimeral plates obtusely rounded; last segment very
small, but well defined. Tail comparatively short, scarcely exceeding in length
/s of the anterior division; genital segment somewhat dilated and equal in
length to the remaining 3 segments combined. Caudal rami narrow, sub-linear
in form, and scarcely at all divergent, equalling about in length the last 2
segments combined; outer edge quite smooth, apex carrying 3 very unequal
sete the inner one much the largest, exceeding in length the tail. Eye very
conspicuous with dark pigment. Anterior antenne scarcely exceeding half the
length of the cephalon, and composed of 6 well defined joints clothed with
slender diverging sete; last joint the smallest, the others not very different in
size. Posterior antenne exceedingly large and powerful, and almost quite nacked;
basal joint thick and massive, forming with the middle joint a geniculate bend;
the latter joint much elongated and sligtly narrowed distally, dactylar joint
cylindrical in form and terminating in,a very strong curved claw. Natatory legs
with the basal part rather broad, rami comparatively short and nearly equal-
sized; spines of the outer ramus very small and quite wanting on the middle
joint in 2nd and 3rd pairs; terminal joint of both rami short, lamelliform, with
densely crowded marginal sete. Last pair of legs with the free joint oblong
oval in form; apical sete comparatively short,

200

Adult male more slender in form than female, with the cephalon less
broad in front. Genital segment widening distally, and generally containing 2
well-marked spermatophores. Anterior antenne of exactly same structure as
in female. Posterior antenne however much smaller than in female, though
built in a similar manner. Posterior maxillipeds rather slender, with the
dactylus very long and nearly straight, terminating in an obtuse point.

Body in both sexes rather pellucid, with very dark translucent intestine,
and moreover exhibiting a bright blue pigment chiefly accumulated in the
anterior part.

Length of young female, immediately before affixion, 1.30 mm.; that
of adult male 1.10 mm.

Remarks.—-The adult ovigerous female of this form was first described
by Nordman in the above-quoted treatise, and has subsequently been more
closely examined by several other authors. The male and the still free-living
female are far less fully known, and I hope therefore that the description and
figures here given will be of some interest.

Occurrence.—In the adult state, as above mentioned, the female of
this form is found firmly attached by the strongly clawed posterior antenne
to the gills of various fresh-water fishes, and when once attached in this
manner, it scarcely at all leaves its hold. In the juvenile state, however, it
is a vagabond animal, swimming about, like the always free-living male, near
the surface of the water in company with other free-living Copepods, from
which it may at once be recognized by the bright blue pigment accumulated
within the anterior part of the body. In this free-living state I have taken the
present Copepod occasionally among plankton collected from some of our
larger lakes. It is very likely to believe, that the female is fecundated by the
male before its affixion.

Distribution.—Lakes of Sweden, Russia and central Europa.

Fam. 15. Clausiide.

General Characters.—Body more or less elongated and narrow, with
no sharp demarkation between the anterior and posterior divisions; the latter
composed (in female) of the normal number of segments. Anterior antenne
small, attenuated, Posterior antenne comparatively short, but distinctly pre-

201

hensile. Oral parts more or less imperfectly developed; the posterior max-
illipeds being in female rudimentary or quite absent. Natatory legs in some
cases normally developed, in other cases much reduced. Last pair of legs
present and extended laterally, being generally uniarticulate. 2 ovisacs present
in female, attached laterally.

Remarks.—The type of this family is the genus Clausia of Claparede,
the systematic position of which. has remained rather questionable, though it
evidently ought to be included within the great section of poecilostomous
Cyclopoida. Another genus apparently. referable to the same family will be
treated of in the sequel.

Gen. 49. Conchocheres, G. O. Sars, n.

Generic Cfaracters.—Body elongated, tapered behind, with the integu-
ments very thin and soft. Anterior division divided into the normal number
of segments, and not very sharply marked off from the posterior. Cephalon
more or less distinctly defined, and in female conspicuously protuberant later-
ally, front without any rostral prominence. Tail in both sexes composed of 4
segments only. Caudal rami slender, with the apical sete much reduced in
size. Anterior antenne composed of 6 joints clothed with comparatively short
sete, and in male moreover provided with a number of largely developed
zstethasks. Posterior antenne in both sexes short and stout, carrying on the
tip a strong uncinate claw. Oral area not far remote from the insertions ol
the antenne, and but little protuberant. Anterior lip bell-shaped, with a small
incision in the middle. Maxille very small, with the masticatory part narrowly
exserted and armed at the tip with 3 hook-like spinules; palp small, lamelli-
form. Anterior maxillipeds with the basal part oblong in form, tapering
distally, terminal part imperfectly defined and provided with a single small
curved spine. Posterior maxillipeds wholly absent in female, but distinctly
developed in male and, as usual, prehensile. Natatory legs present in the
normal number and all having the rami distinctly 3-articulate. Last pair of
legs represented on each side by a small 3-setose joint.

Remarks.—The present genus agrees with the typical one in the com-
paratively slender form of the body, and partly also in the structure of the
antenne and the oral parts. The natatory legs, however, are rather different,
and much more fully developed. On the other hand are the last pair of legs

202

of rather inferior size. It is probable, that the genus Myicola of Whright
is nearly allied to the present genus; but I have had no opportunity of com-
paring them closer, as the paper of that author is not accessible tome. Only
a single species of the present genus is as yet known to me.

107. Conchocheres malleolatus, G. O. Sars, n. sp.
(PI. CXII).

Specific Characters.—Female. Body rather slender, with the anterior
division dilated in front, but narrowed behind. Cephalon only faintly defined
from the trunk, and produced on each side to a very conspicuous hammer-
shaped protuberance, frontal part broadly rounded. Epimeral parts of the
trunkal segments not at all prominent laterally. Last trunkal segment very
small. Tail about equalling in length the trunk, and perfectly cylindrical in
form; genital segment not at all dilated, and scarcely longer than the 2 suc-
ceeding segments combined; anal segment considerably larger than the pre-
ceding one. Caudal rami comparatively slender and narrow, tapered distally
and slightly divergent; seta of outer edge small, and attached a little in front
of the middle; apical setae much reduced in size, the outermost one somewhat
remote from the other 3. Eye wholly absent. Anterior antenne scarcely
exceeding half the length of the cephalon, some of the joints less sharply
defined, the first 2 much the largest, the others rapidly diminishing in size.
Posterior antenne with the basal joint very large and massive, the other 2
abruptly much narrower and somewhat unequal in size, the last one being the
larger; apical claw with a small denticle at the base. Natatory legs of a rather
uniform structure and extended somewhat. laterally, rami comparatively slender
and nearly equal-sized, spines of the outer one small, 3 of them belonging to
the terminal joint. Last pair of legs with the free joint very small, oblong
oval in form, and carrying one lateral and 2 apical seta. Ovisacs large, sub-
cylindrical in form and distinctly curved inwards.

Male rather unlike the female and of much smaller size, with the
cephalon more distinctly defined from the trunk and of quite normal appear-
ance, no trace of the peculiar lateral protuberances present in the female being
detected. Trunkal segments with the epimeral plates well defined and rounded
at the end. Genital segment gradually widening behind and, as a rule, con-
taining 2 well-marked spermatophores. Anterior antenne comparatively larger
than in female, with all the joints well defined, and carrying 5 large recurved

203

estethasks. Posterior maxillipeds distinctly developed; propodos rather narrow
and quite nacked; dactylus long and slender, evenly curved in its outer part.
Colour in both sexes an uniform opaque white.
Length of adult female attaining 3.30 mm.; that of male only 1.60 mm.
Remarks.—The most conspicuous peculiarity distinguishing the above
—described Copepod is perhaps the strongly marked lateral protuberances of
the cephalon in the female, giving the body, as it were, a somewhat hammer-
shaped form; hence the specific name here proposed. Moreover the peculiar
curvature of the ovisacs distinguishes this form from most other Copepoda.
Occurrence.—|I have found this remarkable Copepod occasionally within
the pallial cavity of a species of Newra (N. obesa) taken off the west coast
of Norway. As the parasite is of rather large size in proportion to its host,
it could be easily detected even to the nacked eye as an opaque white mass
shining through the pellucid valves of the shell. No doubt the parasite is
very noxious to the Mollusk, and in all probability quite destroys its repro-
ductory faculty.

Fam. 16. Eunicicolide.

General Characters.—Anterior division of body large, shield-like, with
the segments more or less completely fused together dorsally, those of posterior
division well defined. Anterior antenne attenuated; posterior ones sub-prehen-
sile. Oral parts rather peculiar in structure, though present in the normal
number. Legs imperfectly developed, the 2 posterior pairs being wholly absent.
2 ovisacs present in female attached laterally.

Remarks.—This new family is established, to include the remarkable
genus Eunicicola of Kurz (= Eurynotus Scott), the very aberrant characters
of which prevent its reception within any of the other families here recorded.
The description given by earlier authors (Kurz and Scott) could even leave some
doubt about the right position of this genus within the section of the poeci-
lostomous Cyclopoida, as here defined. On a careful examination of the oral
parts, however, I have found that, in spite of their rather aberrant structure,
they in reality are built on the type characteristic of that group of Copepoda.

204

Gen. 50. Eunicicola, Kurz, 1877.
Syn: Eurynotus, Scott.

Generic Characters.—Body short and stout, with the integuments well
chitinised, and the 2 chief divisions sharply marked off from each other, the
anterior one clypeitorm, and without any distinct segmentation dorsally. Tail
composed in female of 4, in male of 5 segments. Anterior antenne slender
and attenuated. Posterior antenne stout, 3-articulate, last joint armed at the
end with 2 claw-like appendages, each terminating in a peculiar cup-shaped
dilatation. A large circular sucking disk present in female, just in front of the
oral aperture; but wholly wanting in male. Maxille with the masticatory part
greatly produced, and not, as usual, incurved, but abruptly bent backwards and
terminating in a slender, freely projecting knife-shaped extremity; palp of
rather compact structure, and provided at the outer projecting corner with 2
strong and densely ciliated recurved sete. Anterior maxillipeds rather small,
with the terminal part conical in form and tipped with 2 sete. Posterior
maxillipeds in female forming 2 transversely oval gibbous prominences, coarsely
scabrous from numerous scale-like spikes clothing their surface, each pro-
minence exserted inside to a small setiferous lobe; those in male transformed
to very strong, clawed prehensile organs. Only 3 pairs of legs present, the 2
anterior ones biramous, the 3rd pair with only a single (outer) ramus.

Remarks.—This genus was established by Kurz as early as the year
1877, to include a peculiar Copepod found by him parasitic on the skin of a
species of Eunice. The genus Eurynotus of Scott it unquestionably identical
with Kurz’s genus, being indeed founded upon the very same form as that.
observed by the latter author. Of course only a single species of the present

genus is as yet known.

108. Eunicicola Clausi, Kurz.
(Pl. CXII).

Eunicicola Clausti, Kurz, Sitzb. d. K. Akad. der Wissensch. Berlin, I Jahrg. 1877, p. 1, Pl. I & II.
Syn: Eurynotus insolens, Scott.

Specific Characters.—Female. Anterior division of body rounded oval
or almost square in outline, being only slightly longer than broad; dorsal face
evenly vaulted, and exhibiting, somewhat in front of the middle, a slight trans-
verse furrow apparently indicating the limit between cephalon and trunk; ventral
face flattened; front a little bulging, but without any true rostrum. Trunkal part

205

of body obtusely rounded behind, and without the slightest trace of a
segmentation dorsally, whereas ventrally well-marked chitinous stripes are
seen, running transversally between the insertions of the legs. Tail scarcely
exceeding half the length of the anterior division and partly overlapped in
front by the trunk; genital segment rather dilated in its anterior part,
being almost twice as broad as it is long; the succeeding segments gradu-
ally attenuated; anal segment comparatively small and deeply incised behind
in the middle. Caudal rami scarcely longer than the anal segment and
somewhat divergent; seta of outer edge attached near the end; apical sete
rather unequal, the inner mediate one being the longest and somewhat
exceeding half the length of the tail; innermost seta very small. Eye
quite absent. Anterior antenne about the length of the cephalic part of the
body, and composed of 7 well-defined joints clothed anteriorly with com-
paratively short sete; Ist joint rather broad; 2nd joint much the largest, car-
rying behind at the base a group of 4 short bristles and at the end a long
densely ciliated seta; the remaining joints rapidly diminishing in size. Posterior
antenne rather strongly built, last joint of a somewhat irregular form, and
provided at the end, in addition to the 2 peculiar cup-shaped claws, with 4
rather strong and partly ciliated sete. Sucking disk very large and conspicu-
ous, with densely crowded radiating fibres, and finely ciliated at the edge.
The 2 anterior pairs of legs with the outer ramus 3-articulate and longer than
the inner, which only consists of 2 joints. 3rd pair of legs considerably smaller
and without any inner ramus, outer ramus biarticulate. Ovisacs slender, cylin-
drical in form, each containing a rather limited number of ova atranged in a
Single series.

Male of rather smaller size than female, and having the trunkal part
of the body somewhat less broad behind. Tail comparatively more slender,
with the genital segment widening behind and terminating on each side in
an obtuse projection. Both pairs of antenne exactly as in the female. Sucking
disk however quite wanting. Posterior maxillipeds very powerfully developed;
basal joint short with a strongly denticulated process inside; propodos much
dilated, with the palmar edge bulging at the base and densely clothed with
small spikes; dactylus strong and curved.

Colour not yet ascertained.

Length of adult female 0.90 mm., of male 0.65 mm.

Remarks.—This form was first recorded by Kurz in the above-quoted
Journal, and was several years afterwards described by Scott under another
name, viz., Eurynotus insolens, the paper of Kurz being at that time unknown

27.— Crustacea

206

to him. The structure of the oral parts have not been satisfactorily made out
either by Kurz or by Scott, and the signification of the peculiar sucking disk
occurring in the female was quite misapprehended by Kurz, who believed it
to enclose the oral aperture, a pair of chitinous rods joining this disk on each
side and serving for its support being erroneously described as mandibles.
Occurrence.—Two female specimens of this peculiar Copepod were
found last summer at Riser, south coast of Norway, among dredged material
taken up from a depth of abouth 50 fathoms, and some other specimens,
among them an adult male, were recently picked up from the bottom-residue
of a large collecting bottle containing various marine animals obtained by Mr.
Kjer in the Christiania Fjord, near Drebak. Kurz, as above mentioned, found
this form parasitic on a species of Eunice (E. Claparédi), and no doubt this
form also off our coasts may be stated to infest some nearly-allied worms.
Distribution.—British Isles (Scott), Mediterranean at Triest (Kurz).

CORRECTIONS AND ADDITIONS.

Page 8. For Oithona helgolandica, Claus read:

Oithona similis, Claus.
Oithona similis, Claus, Die Copepoden Fauna von Nizza, p. 14.

Remarks.—On a closer consideration, I am now led to the conclusion,
that the 2 forms recorded by Claus under the names O. helgolandica and
O. similis are in reality very distinct species, the former being in all pro-
bability identical with the form subsequently described by Giesbrecht as O. nana.
This species, which accordingly must bear the older name helgolandica, has
not yet been observed off the Norwegian coast. For the northern species
described page 8 as O. helgolandica the specific name similis given to it by
Claus ought of course to be retained.

Page 9. Add the following genus and species:
Gen. Paroithona, Farran, 1908.

Generic Characters.—General form of body resembling that in Oithona,
the 2 chief divisions being sharply marked off from each other. Cephalon
distinctly defined from the first trunkal segment, and having the front rounded
off below, without any rostral projection. Tail slender, with long diverging
apical sete. Antenne and oral parts on the whole built on the same type as
in Oithona, except that the mandibular palp is somewhat simpler in structure.
Natatory legs with the inner ramus in all pairs only composed of 2 joints.
Last pair of legs very small.

Remarks.—This genus, recently established by Farran, is closely allied
to Oithona, {rom which it is chiefly distinguished by the inner ramus of all
the natatory legs being only biarticulate. Mr, Farran has recorded 2 species

208

referable to this genus, the one, P. parvula, from the west coast of Ireland,
the other, P. pulla, from the Indian Ocean. The first-named species also
occurs off the Norvegian coast, and will be described below.

Paroithona parvula, Farran.
(P!. CXIV).
Paroithona parvula, Farran, Second Report on the Copepoda of the Irish Atlantic Slope.
Fisheries Ireland. Scient. Investig. 1906, II, p. 89, Pl. X, figs. 1—13.

Specific Characters.—Female. Body moderately slender, with the
anterior division regularly oval fusiform in outline, greatest width equalling
about half the length and occurring a little in front of the middle; frontal
part obtusely blunted and evenly rounded below, without the slightest trace
of any rostrum. Tail exceeding somewhat half the lenght of the anterior
division, and very narrow, cylindrical in form; genital segment only slightly
dilated in its anterior part and longer than the 2 succeeding segments com-
bined; anal segment fully as long as the preceding one and slightly widening
distally. Caudal rami quite short, not nearly attaining the length of the anal
segment, and slightly divergent; seta of outer edge attached near the base;
apical sete very unequal, 2 of them excessively prolonged and crossing each
other at the base. All integuments very thin and fragile. Anterior antenne
not attaining the length of the anterior division, and composed of 9 joints clothed
with partly very long and diverging sete; some of the joints being however
less perfectly defined. Posterior antenne biarticulate, proximal joint nearly
twice as long as the distal one. Mandibular palp armed at the inner pro-
jecting corner with a single strong claw-like spine clothed on both edges with
a limited number of slender spikes; inner ramus very small, outer well developed,
imperfectly 3-articulate, and provided with 5 long densely plumous sete. Max-
ill and maxillipeds of a structure very similar to that in Oithona. Natatory
legs rather slender and partly extending laterally; inner ramus in Ist pair about
the size of the outer, in the other 3 pairs much smaller; outer ramus in all
the pairs distinctly 3-articulate, its terminal joint having outside in the 2 an-
terior pairs 2 spines, in the 2 posterior pairs a single spine; apical spine of
this ramus in the 3 posterior pairs exceedingly long and slender. Last pair
of legs apparently represented on each side by a single short seta arising from
a knob-like prominence.

Colour not yet ascertained.

Length of adult female 0.52 mm,

Male unknown.

209

Remarks.—This form was described and figured by Mr. Farran in the
above-quoted Report as the type of his genus Paroithona. It may easily be
recognised from the 2 Norwegian species of Oithona described in the present
work by its small size and the somewhat less slender form of the body, in
which respect it however resembles some exotic species of that genus. From
the Indian species, P. pulla Farran, it differs among other things in the
distinctly 3-articulate outer ramus of the Ist pair of legs, this ramus being in
the said species, like the inner, only composed of 2 joints.

Occurrence.—The occurrence of the present form off the Norwegian
coast has first been stated by Mr. Farran, who found it not unfrequently in a
plankton-sample taken from deep water in the Hundfjord, west coast of Norway
(Nordfjord), some of the specimens having kindly been sent to me for ex-
amination. J am moreover enabled to state its occurrence in another locality
of the Norwegian coast, 2 or 3 female specimens having recently been picked
up from a sample of pelagic Copepoda taken by Mr. Nordgaard in the Herlo-
fjord, near Bergen.

Distribution.—West coast of Ireland (Farran).

Page 14. For Cyclopina brevifurca, G. O. Sars, read:
Cyclopina Schneideri, Scott.

Cyclopina Schneideri, Scott, Notes on some Copepoda from Arctic seas, collected by Canon
A. M. Norman. Ann. Mag. Nat. Hist. Ser. 7. Vol. XI, p. 6, Pl. 1, figs. 1—6.

Remarks.—1 am now disposed to regard the form described by me
on p. 14 as C. brevifurca to be more properly identical with the species
recorded by Scott from east Finmark under the above name. True there are
some apparent differences, chiefly as regards the size') and the structure of the
last pair of legs (according to the figure given); but in all other respects the
agreement between these 2 forms are so complete, that I find it unreasonable
to keep them apart as distinct species.

Page 16. Add the 2 following species:

Cyclopina euacantha, G. O. Sars, n. sp.
(Pl. CXV, fig. 1).

Specific Characters.—Female. Body not very slender, with the an-
terior division oval in outline, greatest width exceeding half the length and

1) Scott gives the length of his specimen to rather more than 1 mm.

210

occurring somewhat behind the middle. Cephalic segment longer than the 4
succeeding segments combined and slightly narrowed in front. Tail somewhat
exceeding half the length of the anterior division; genital segment only slightly
dilated in its anterior part, and about the length of the 3 succeeding segments
combined. Caudal rami moderately produced and rather narrow, being scar-
cely at all divergent; seta of outer edge attached about in the middle; apical
sete normally developed. Anterior antenne slender and elongated, exceeding
in length the cephalic segment, and composed of 19 well-defined joints, 1st,
2nd, 4th, and 7th the largest, the other joints very small. Posterior antenne
with the terminal joint much shorter than the antepenultimate one. Natatory
legs comparatively short and stout, with the spines of the outer ramus unusu-
ally strong, dagger-like. Last pair of legs biarticulate, proximal joint rather
broad, being angularly produced outside, distal joint considerably longer, but
much narrower, oblong in form, and armed with 3 very strong dagger-like
spines, 1 apical and 2 lateral ones.

Colour not yet ascertained.

Length of adult female 0.80 mm.

Male unknown.

Remarks.—This form, which has briefly been mentioned on page 11,
was observed many years ago by the present author, and was at that time
subjected to a careful anatomical examination; but both the specimens and
the dissections have unfortunately been lost, so that I have had no opportunity
of renewing my investigation. The figures given on the accompanying plate,
which are copied from my earlier drawings, will however at once show it to
be a very distinct species.

Occurrence.—The specimens of this form observed were taken off the
Lofoten islands, at Skraaven, from a depth of about 12 fathoms, sandy bottom.
Only a few female specimens were obtained, none of them carrying ovisacs.

Cyclopina pygmea, G. O. Sars, n. sp.
(Pl. CXV, fig. 2).

Specific Characters.—Female. Body resembling in shape that in C.
gracilis, though comparatively more slender, with the anterior division oblong
oval in outline, greatest width only slightly exceeding half the length and
occurring about in the middle. Tail rather narrow, with the genital segment
scarcely longer than the 2 succeeding segments combined. Caudal rami con-
siderably produced, exceeding in lenght the last 2 segments combined, and

211

slightly divergent, being somewhat contracted in the middle, but a little
widening towards the end; the outer corner of which is produced to a small
dentiform projection; seta of outer edge attached considerably in front of the
middle; apical sete rather slender, the 2 middle ones coarsely spinulose at the
edges for some part of their length; seta of inner corner much longer than
that of the outer. Anterior antenne comparatively short, not nearly attaining
the length of the cephalic segment and, as in C. gracilis, composed of only
10 joints, the 6th being much the largest and about equalling in length the
outer 4 joints combined. Posterior antenne, oral parts and natatory legs
resembling in structure those parts in C. gracilis. Last pair of legs also rather
similar, though comparatively of somewhat smaller size. Ovisacs rather small
and closely appressed to the sides of the tail.

Colour whitish grey.

Length of adult female not exceeding 0.42 mm.

Remarks.—The above-described form is closely allied to C. gracilis
Claus, and indeed at first I was inclined to regard it as merely a small variety
of that species. Having however subsequently met with this form in many
different localities and always found its characters pretty constant, | am now
of opinion that it should be kept apart as a distinct species.

Occurrence.—|I first observed this form at Skutesnes SW coast of
Norway, where it occurred not unfrequently together with C. gracilis, from
which it at once distinguished itself by its much smaller size. The same form
has subsequently occurred to me in the following localities of the southern
coast: Farsund, Lillesand, Grimstad and Risgr.

Page 32. For Cyclop strenuus, Fisher, read:

Cyclops pictus, Koch.
Deutschlands Crustaceen, Myriapoden und Arachniden. Heft. 21, Pl. 1.

Remarks.—As it appears to me beyond doubt, that Koch’s species is
the same as that subsequently described by Fischer as C. strenuus, | think
that, according to the rules of priority, the naine proposed by the first named
author must be retained for the present species.

212

Page 109. Add the following genus and species:
Gen. Scottomyzon, Giesbrecht, 1897.

Generic Characters.—Body short and stout, with the anterior division
very sharply marked off from the posterior and greatly dilated, especially in
female. Rostral prominence obtuse, incurved. Tail very small and consisting
in female of only 3, in male of 4 segments; genital segment in both sexes
greatly tumefied. Caudal rami short, with the usual number of sete. An-
terior antenne not much produced, but, as in most other Ascomyzontide,
divided into numerous short articulations; those in male distinctly hinged near
the end, but without any supplementary estethasks. Posterior antenne with
the appendicular (outer) ramus more fully developed than in the other Asco-
myzontide. Siphonal tube quite short, with large opening. Mandibles with
the masticatory part not much produced, palp small, unisetose. Maxillz with
both lobes well developed and nearly equalsized. Anterior maxillipeds much
more strongly built than the posterior. Natatory legs with the rami compara-
tively slender, terminal joint of the outer one with only 2 spines outside.
Last pair of legs small, biarticulate.

Remarks.—This genus was established by Giesbrecht to include a
species first described by T. Scott and referred by him to the genus Derma-
tomyzon of Claus. It is chiefly characterised by the short and stout form of
the body, the unusual size of the outer ramus of the posterior antenne and
the very strong development of the anterior maxillipeds; finally by the peculiar
Structure of the siphonal tube. Only a single species is as yet known.

Scottomyzon gibberum (Scott).
(PI. CXVI).

Dermatomyzon gibberum, Scott. On some new and rare Crustacea from Scotland. Ann. Mag.
Nat. Hist. Ser. 6, Vol. XIII, p. 144, Pl. IX, figs. 10—14.

Specific Characters.—Female. Form of body very short and compact,
more so than in any of the other known Ascomyzontide. Anterior division
of somewhat varying shape according to age, being in young specimens sub-
clavate or pear-shaped, in fully adult specimens nearly circular in outline, with
the greatest width about equal to the length. Cephalic segment exceedingly
large, with the lateral edges quite evenly arcuate throughout. The succeeding
segments rapidly diminishing in size, and having the epimeral plates rounded
off. Tail very short, being scarcely 1/5 as long as the anterior division; genital

213.

segment much dilated, nearly twice as broad as it is long, the 2 succeeding
segments small. Caudal rami likewise of inconsiderable size, scarcely longer
than they are broad, and somewhat divergent; apical sete not much produced
and somewhat spreading. Anterior antenne scarcely more than half as long
as the cephalic segment, and composed of 18 joints, the Ist and 3rd of which
are the largest. Posterior antenne with the terminal joint comparatively small
and of conical form, being provided with a short lateral seta and a rather
feeble apical spine accompanied by 2 unequal bristles; appendicular ramus
almost as long as the penultimate joint and carrying on the tip 3 short bristles.
Siphonal tube nearly oval in form. Mandibles with the extremity quite simple,
without any denticles. Maxille with the inner lobe a little shorter and stouter
than the outer, and carrying on the end 3 rather strong subequal and densely
ciliated sete; outer lobe sublinear in form and provided with 4 more slender
apical sete. Anterior maxlllipeds very powerful, with the terminal claw ex-
ceedingly strong and abruptly curved at the tip in a hook-like manner. Post-
erior maxillipeds of quite normal structure. Natatory legs with the inner ramus
in the 2 anterior pairs about equal in size to the outer, in the 2 posterior
pairs rather smaller; spines of outer ramus in all the pairs rather small. Last
pair of legs with the distal joint narrow oblong in form and provided at
the tip with 2 comparatively short sete and inside with a very minute bristle.
Ovisacs globular in form, each containing a very limited number of ova.

Male much smaller than female, and having the anterior division of
the body far less tumefied. Tail comparatively more fully developed, with the
genital segment somewhat larger and, as a rule, containing 2 globular sper-
matophores, genital lappets each tipped by a long seta pointing obliquely
outwards. Anterior antenne more strongly built than in female and composed
of only 16 joints, the last 2 of which form together a very movable terminal
part admitting of being bent against the preceding part.

Body in female of a more or less vivid brick-red colour, that in male
much paler.

Length of adult female amounting to 0.56 mm.; that of male 0.45 mm.

Remarks.—This form, as- above mentioned, was first described by T.
Scott aS a species of the genus Dermatomyzon of Claus, but was subsequently
justly removed from this genus by Giesbrecht, to form the type of his new
genus Scottomyzon. It is an easily recognisable form, which cannot be con-
founded with any of the other Ascomyzontide.

Occurrence.—I have recently found this form parasitic on our common
starfish, Asterias rubens taken at Riser, south coast of Norway, as also in the

28.—Crustacea.

alee

upper part of the Christiania Fjord. Owing to its small size, it is not easy to
detect the parasite when still attached to its host, and it was indeed only after
immersion of the starfishes in a feeble solution of alcohol that, by an ex-
amination of the bottom-residue of the bottle. I succeeded in getting sight
of the detached parasites. The greater number of the specimens thus secured
were of the male sex, and only very few female specimens were obtained,
among them a fully adult ovigerous one, that here figured. Mr. A. Scott has
procured this form by the same proceeding from starfishes collected of the
British coast.
Distribution. British Isles (Scott),

Page 172. Add the following species:

Pseudanthessius dubius, G. O. Sars, n. sp.
(Pl. CXVID.

Specific Characters.—Female. Body moderately slender, with the an-
terior division comparatively broad and regularly oval in outline, greatest
width equalling about ?/; of the length and occurring in the middle. Cephalic
segment very large, and scarcely exhibiting any transversal suture behind, front
narrowly rounded. Last trunkal segment very small. Tail slender, equalling
in length about */s of the anterior division, and only composed of 3 segments,
the Ist of which (the genital segment) is, as usual, much the largest and sub-
fusiform in shape, being divided in the middle by a transversal suture into 2
parts, the anterior one somewhat bellshaped, the posterior rapidly tapered; the
2 succeeding segments sharply marked off from each other, both of narrow
cylindrical form, fully twice as long as they are broad. Caudal rami very
slender and narrow, being nearly as long as the last 2 segments combined,
and slightly divergent; seta of outer edge attached somewhat beyond the
middle; apical sete rather unequal, the 2 middle ones being, as usual, much
longer than the other 2, which are very small, especially that attached to the
outer corner. Anterior antenne slender and narrow, being composed of the
usual number of joints clothed with moderately long sete; 2nd joint the largest,
last joint very small. Posterior antenne likewise rather slender, though a little
shorter than the anterior ones; 2nd joint about as long as the last 2 com-
bined; terminal joint armed at the tip with a single well-developed claw
accompanied by 5 strong curved sete. Maxille not examined. Anterior max-
illipeds with the terminal process only slightly curved. Posterior maxillipeds
with the propodal joint fully as large as the basal one, and provided inside

215

in the middle with a very small spine accompanied by a likewise small bristle;
dactylar joint conical in form, with a minute spinule at the base. Natatory
legs resembling in structure those in the type species (P. gracilis) ; inner ramus
of 4th pair however of larger size and densely ciliated on both edges, the
outer one exhibiting in the middle a well-marked dentiform projection. Last
pair of legs, as in the other species of this genus, quite rudimentary, being
represented on each side by a short spine and 2 sete, all attached immediately
to the corresponding segment.

Body, in the living state of the animal, very pellucid, of whitish colour,
with orange-colured intestine and light fuscous ovarial tubes.

Length of adult female slightly exceeding 1 mm.

Male unknown.

Remarks —The most prominent peculiarity of the present species is
the composition of the tail of only 3 segments, in which respect it differs not
only from the other species of this genus, but from all the known Licho-
molgidz. The structure of the several appendages, however, is in full accor-
dance with that found in the genus Pseudanthessius, to which it accordingly
must be referred. In the very narrow and produced caudal rami it resembles
the form recorded by Brady as Lichomolgus Thorelli, and indeed at first I was
inclined to regard it as identical with that species. The structure of the caudal
segments, however, as also that of the last pair of legs, is, according to the
figures given by Brady of these parts, so totally different that an identification
of these 2 forms is inadmissible.

Occurrence.—Only a single female specimen of this form has hitherto
come under my notice. It was taken many years ago olf the west coast of
Norway, the exact locality not being noted, and, after a coloured drawing was
made from the still living animal, it was submitted to a careful anatomical
examination. The figures here given are copied from the drawings made at
that time.

Page 189. Add the following genus and species:

Gen. Lichomolgella, G. O. Sars, n.

Generic Character.—General form of body somewhat resembling that
in the genus Machrocheiron. Tail however comparatively shorter and stouter,
with the genital segment (in female) rather massive and exhibiting behind 2
peculiar ventral lappets confluent in the middle. Anterior antenne unusually

216

short, though composed of the normal number of joints. Posterior antenne
likewise short and stout, distinctly prehensile. Maxille not examined. Anterior
maxillipeds of quite normal structure. Posterior maxillipeds, however, rather
unlike those in other female Lichomolgide, the propodal joint being consider-
ably dilated and the dactylar joint claw-like. Natatory legs with the rami com-
paratively short and stout, and having all the spines very strongly developed;
inner ramus of 4th pair very short, uniarticulate, with 2 apical spines. Last
pair of legs represented on each side by a small, but well defined bisetose joint.

Remarks.—This new genus is established, to include a small Licho-
molgid, which I have found it impossible to range within any of the other
genera, though it exhibites some affinity both to the genus Macrocheiron and
to Pseudantessius. With the latter genus it agrees in the structure of the 4th
pair of legs, the inner ramus of which is uniarticulate; but the last pair of
legs are rather different, having a well defined bisetose joint, as in most other
Lichomolgide. In the structure of the genital segment and of the posterior
maxillipeds it differs conspicuously from any of.the other genera.

Lichomolgella pusilla, G. O. Sars, n. sp.
(PI. CXVIII, fig. 1).

Specific Characters.—Female. Body moderately slender, with the
anterior division oval in. outline, greatest width equalling about */s of the length
and occurring in the middle. Cephalic segment very large, occupying almost
half the length of the body, and exhibiting near the middle a fainte arcuate
transverse suture. The 3 succeeding segments rapidly diminishing in size, and
having the lateral parts evenly rounded off. Last trunkal segment very small.
Tail rather short, not nearly attaining half the length of fhe anterior division;
genital segment comparatively large, exceeding in length the remaining part
of the tail, and exhibiting on each side, at some distance from the end, an
angular corner; ventral lappets each tipped by a slender seta pointing obliquely
outwards; the 3 succeeding segments subequal in size, and fully twice as broad
as they are long. Caudal rami very short, being scarcely longer than the anal
segment; seta of outer edge attached about in the middle; apical sete partly
brocken in the specimen examined. Anterior antenne unusualy short and
stout, but composed of 7 well-defined joints clothed with slender sete. Post-
erior antenne about the length of the anterior ones, and rather strongly built;
2nd joint considerably longer than the outer 2 combined, and projecting at the
end behind in a rounded corner; penultimate joint very short and armed at

oN

the end anteriorly with a slender biarticulate claw and 3 small bristles; terminal
joint carrying on the end 5 curved sete and a slender claw of same appearance
as that on the penultimate joint. Posterior maxillipeds with the propodal
joint considerably dilated and oval in form, carrying somewhat beyond the
middle a short spine and in front of it a slender seta; dactylar joint exserted
in the form of an almost straight claw with a slender spinule at the base.
Natatory legs with the rami in the 3 anterior pairs nearly equal-sized: inner
ramus of 4th pair, however, much reduced in size, forming a single oval joint
with 2 somewhat unequal spines on the tip. Last pair of legs with the tree
joint rather small and oblong in form; apical sete not much produced and
subequal in size.

Colour not yet ascertained.

Length of the specimen examined 0.45 mm.

Male unknown.

Remarks.—The above-described form may be easily distinguished from
any of the other Lichomolgide by its small size, the unusually short anterior
antenne and the structure of the tail.

Occurrence.—Only a single specimen of this form, an apparently full-
grown female, has hitherto come under my notice. It was picked up from a
sample taken several years ago at Skutesnes, SW coast of Norway, from a
depth of about 20 fathoms.

Page 193. Add the following species:

Onc@a minuta, Giesbrecht.
(PI. CXVIII, fig. 2).

Oncea minuta, Giesbrecht, Fauna & Flora des Golfes von Neapel, Pelagische Copepoden,
p. o91, Pl. 47, figs. 3, 6, 26, 46, 59.

Specific Characters.—Female. Body moderately slender, with the an-
terior division oval fusiform in outline, greatest width about half the length
and occurring in the middle, dorsal face evenly vaulted throughout. Last
trunkal segment extremely small. Tail not attaining half the length of the
anterior division; genital segment evenly dilated in the middle and slightly
longer than the remaining part of the tail; anal segment larger than either of
the 2 preceding segments. Caudal rami comparatively short, scarcely attaining
the length of the anal segment; seta of outer edge attached about in the
middle; apical sete not much produced, that of the inner corner very small,
shorter than that of the outer. Structure of the several appendages very similar

218

to that in the 2 other Norwegian species. Inner ramus of 4th pair of legs,
however, wanting the plug-shaped process between the 2 apical sete!). Last
pair of legs extremely small, with the free joint nodiform.

Colour not yet ascertained.

Length of adult female scarcely 0.46 mm.

Remarks.—| cannot doubt that the above-described form is that recorded
by Giesbrecht as O. minuta. Beside by its small size, it differs from the 2
other Norwegian species by the form and relative size of the genital segment,
and by the very small innermost caudal seta.

Occurrence.—Two female specimens of this form were recently found
among some pelagic Copepoda kindly sent to me from Mr. Nordgaard, who
obtained them in the Herlofjord near Bergen.

Distribution.—North Atlantic Ocean, Mediterranean, Pacific, Indian Ocean.

1) True, Giesbrecht, asserts that such a process is present; but I suspect that the leg
he figures is in reality not the 4th, but the 3rd, in which this process is well marked.

Acontiophoride ........
Acontiophorus 106,
ClONGALISH EL eee. oe
OMNES 5 ogcocogar
scutatus
Agetus
Antaria

EXONSUS 32504...
ATlLOLrOSUs....;
|B) OSE ie ie ene Re A
AIVAQIINCEDS ig wis acetone ss
Normani....
orbicularis
papillatus
ASCOMLIYZ0N: sas ee
QSUCLOCIELES ar nee
SOCCRE «Mngt. 5s. eee ae

124,

WOM TNGE eg ie hae
EiUjepangins. oso}.
parvum
SUNHIQUSR Me See le
‘spongiophilum
Thompsoni
Dorel : sees
VINESCENS \ = sea eae
Ascomyzontid@.........
Asterocheres

Palhjeborgi. .< ya a
MARVIISHS ca. 6 cos i eee
siphonatus ........
WIOlACEUS. 2254. ee

Page

109 |

110
107
110
110
194
190
145
122
122

132 |

88

124 |

130
138 |

127,
84
85
88

102
91

90 |
87 |
92 |

89

90 |

94

95 |

92
83
84
91
86
92
88

98 |

RNID Ex

Page
Asterocherida ~.. 25.71/32 83
ANSUMOG NSIS S45 oogdb oc 84
Bomolochtus)....: 22224. 143
Bradypontius <22255 Jae 124
ANGI side 5 S12 so 124, 125
COUAQLUS Mn ote nee 128 |
Givelitens... 64 secs 126, 127
MAZHICEPS «2.8... 124 |
IN) O lage ae ee eee 127
PApUGtus: 223225.8 ee 126
Galisidtum s:. 2.2 2442228 138
vagabundum ..... 138, 141
GaNncerilld, 2. an se ae 139
CUDTAU DEM ss arse eee, oe 139
Cancerilid@ ie... 65 oe 135 |
@latisiatss . tac. bess eee 201
Clausidud@ = . 5.4524: 144 |
Gusidiiitives {2 acc Aon oe 144
Glaistid@ (2. eee 200
Clausomyzon ....<. sas 100
Sracilicaudas 222.4 A... 101 |
Gollocheres . 252.4 100, 105
PRACUICAUdA = =v 5205.0% 101
eCleGansS' - rcpt eae eee 105
Goma. ankaks sate 190
Conchocheres 2) 2259} 201
MAUCOLALUS Sarena ae 202
Corycella c. ta 5... he 195
Coryc@ide% sii. 08 es 194
GOFYCRUS® Veer ss 194
QHEVICUS 350525 ee 196
PEMMANNS) 2225209: PAV 196
ODUISUS 5 oases Se sa ae 197
Cripropontius ..52.02 2) * 130
NOGA cies e555 PPO 130
CrYPLOPONTUS® ia. 3 120

| Page
| brevifurcatus ........ 120
| ;Gyclopellay ayes aus ee ee 20
| CYClOpettss ncn asa Ber 18
difficilisn 2.42 18

| Cyclopicera...... 84, 95, 100
elegansy.3545.25 SRR: 96
gracilicauda .......... 101
fata ce cues aares es 90, 91

|) MiP TI PES Ae Aes es 95, 96
Gyclopid@ nea ss.. 2 ton 22
n@velopona. cee es LOU 10
|, PC@lavish - ape eee 2 2 24, 25
breviturca:. 2.24. Sees 14
CLO LOANS 25 his a tg es 15
CUGCONTNOG ©7272 i a6 11, 209
PRACUIS) o)2 4. Sees 11
litoralisisas see nee We es)
longicaudata./........ 1]
LONLICOTNIS. ERA 12
longifarea 3. 21. Pe: 11
NOFVESICA 44 2554.42 il ey
pusilla hy. 6c. 2 s.2 ee ae it
PYBINOA Ss soc e ns 210
Schneidert .. 22 SMES 209

| Gyeloprielia = ein ts 16
i) MGUMIGUIA ocean 16
Gyclopinid@. .2 00. 1/203: 9
WGVELODS: iA on co eae 30
abyssicola 7. (Pe. 53

| abyssorum. «. Pie 2ner 33
ACGVOLEUS...: 2. bee 29, 30
ACALISS.ois'h cys aerator 71
allinisS: .¢ . lee eee 80
ANDHOWS .acancesade 68, 69
AME TICAMUS Hee tet tate 4]
anmiulicormis :. 5.262: 68

=

Page Page Page
Atmaudi: nce rtcets Le ys) ODSOlEtUSH 5 dese eee OO | be MTLCLEGla a) ae 204
AtLEMUAtMS is ee ney 55 OILMONOId ES owaee es wee 59 Clansit iene Cee 204
DICOLIOD Ve nee eee 56 odessanlsss ne 47; ASU Eumicicold@ 74 ae 203
bicuspidatusty.-2)-— 47 oligarthrus) 9: 4s LT | SEAMOUNTS re, peer eoncee 204
DISCLOSUS Ber mig ich 48 orientaliSnee. aaeer 54, 59 INSOLENS.)9e tela eee 204
biStriatiSmerers eey-cae' 67 pachycomus"- 27 5 eee OO! AUP EE sien at hs ace ees 23
brachytinus 25-5... (Nye PARCUS See cste eae 44, 45 CULLLCOTNISHL ae eae Pail
brevicaudatus...... 32, 33 DiCCUS wee Gets eae 32, 211 longicauda@., ws eee 24
breviconmisie-ane ss. 40, 41 phaleratus. 26:25 78 TOOUSLAS ae eee 26
brevispinosus...... AeeaOa ne IPODDel. oo. ast TF) “Gallopontiise = tans 118
canthocarpoides .... 78, 79 PraSinus <hr hee 70 Neh ateal | Clips esas fw gt oc 118
GU DIIDtUS Ee peeks ks - 43 PIOXIMIUS Sait oan pce 72 PASSER AM; cea ete 118
(CHET g ead dices Ure) PYSmeUS 8 . a. -k. 80, 81 IROLOIIOIUIS Ses ancecs 118, 119
COMMPACHUSS ae ge) ee Tf \\ pulchellus:...... 37, 338, WAT |\idelievelopsts eee ee 28
€faSsicOnNis) 4.2064. 81, 82 quadricornis ... 32, 34, 40 IMALNICEPS 2s omen 29
CRASSICQUGES 05. 20> : 49 KOUUSTUS 1 oon eee 45 PEOPINIGVIIS . 2 eee 28
christianiensis...... 29, 30 Rubelltis. 2. = meee: oon) “temicyelops = Aeneas 145
COLOMAISHe ee oe 65, 66 SHIT 6s ooGnd > one gt, PUrpBkeus..) ase 146
ChaASSUSHee hee. sna Ol nO2 |) Se Scountteldi 4.2) a DGD LenLa ie) LO 174
Cunningtont.: -.2 yoink DO)" RSEUTIER | acc. Jeb eee 36.| finmarchica. 20.90: 179
GENCIZICLIS: Cot... ae seals 50 serrulatus ..... Hi, 12. 733 MAXIM al... «os ates TAS)
@igpnanus 0.50%. S2E OO SISTIALIS 47. eee 65, 66 PQTUG . Seo aee 176
@istinctus: 0.0 eg net Gfaliaysimplex:..so.>s, aes 58, 59 prenensiliss \ eae ee 178
Dibowskyi.;.253-..52: 62 Speratus ....-.aaneiee 72° \teonostiata’. geen eee 175
CUARGE MEA oe oitt in ae 58 Spinitet:. 22.6... ee 58. || otenuicaudis’, hare 180
Gleganis) eae 2). mtate 75 SINUS <3.) eee B2 |) MOalidd ©... 03. ae 175
eloncatusy. 225.2% 44, 45 tenuipes .....:. <p dd;ueey|) Tlersiliagy se. or see 144
LSUAVUT INS Sasa oem Co 58 Dhomasi-...:... nase 48. “Fersiltide 2: 2. ee 144
HiMMDTIALHS |) «ce ee ashi: 81 WOTICONS: |... *.4ie 54% | Hersiliodes {2 tence 145
RUS CUS papena nacre 4 65, 66 WaAnitSy 2 5). cca ce (2s afoul Mee lseneenies.. tee 145
LOOSE ate ee 3. KOR SG @MemMalis.s s .2.0 5 aes 44, 465 Pultintt. 2. ore tae 145
SraciliCOnMiSe......0. 2 .\a: B/-)) | pwicinus...0%.0: ole 37 THOMpPSONi «..,.....- see 145
PRACHIS ees oso pots 63 Willd GIS) 7.8.75 ioe 0 ee 40, 41 | Hippomolgus... 2. Bess: 147
SYCIMUS 225 No ateae 68, 69 WULEATIS . oc > 5). sae AQ) | Afurcifer. ..0. aces 148
helgolandicus...... 47, 48 | Dermatomyzon......... 95%| iLentocyclops.. ae 70
hyalinus ..2... 59, 60, 61 eibbertine |. y.. eee 212 QRUIS He oe cya (ik
WO SEMB tere eee oeeenc els 41, 42 ISLIDES =. = eee Q5° |. «billjeborgt%.: "ae 73
WUSUCTISS eh. oes Sota ||) Woridicola’ ...... eae 161 | macruroides ......... 74
WCUSEFIS Zi cc aide Gata OFA BOGUS! crocs 5 aN 161, 162 MIGCTUTUS ./), 1 Seas 75
WORE ULAUS I, «2, se \acny: O0 i PDyspontitde.. 1. > sae 117 SUETALUS =. 25 ners 72
lascivtise ee ee [SAO MOMSPONUUS .:.. 2.2.0.2. L183) ‘Leptomyzon « ....saeae 105
Meuckartion 2202) whe 58 Norman, 2%. 2. ua4hsene 130)) elegans’ 2. shiva 105
Lubpockd) ..5.... a3 BERL ASS PM USEVIOCUS 0... Se aah? ki8 | Liehomolgella . jae 215
MUCIDULUS es Se EEN | MIVSETOSUS:: 2 cue as ae BE 132 Pusillare see ee ee 216
MIAALENSIS 2s. cts. fo; 46 | (Eehinocheres..... .: a2ss6 93%) Lachomolside: ieee 149
IMACKUTOIdES =. . Ai ewe 74 MIMUMUUES 05. Sat. oe See O4°| Lichomolgus . 2) hoes 150
MUACHMENS eis siya psysis 75 WEOIQCEUS, om oo anh 93 aberdonensis . ..s3:ei, 145
magnicepS......... 295330) Eolidicola: 242... -acuer 161 QRUESR cee Bak oe eel 161
MINES Aa. hoe cee BOM Nema ees eta 161, 162 arenicola”, ..c2 : a: 182, 183
MANUS Bec, iste daa. eS O27 PARCUSTUIAC <./..... weaves 197 GaN ae 157
MeCHeGIIS! E55. wae Poel bAnonsilus es. ck Le ue 198 chromodoridis ........ 161
Bigticauda. ....: ice WN D5) Siecboldiges aan ee ener 199 CONCISE see 161, 162

68 |

Page
dondicolamacecaase 161
TOVPOULO ion 6 tc6 aieys es 153
HHUA Ae oF 2). 5 < ehee es 156
MLELCONASs Asis fe ne « Sheltie 163
[Ni] SYES Pe 8 cee eee Syke a 169
littoralis .... 145, 146, 147
MATOUNALUS I) s\n a oats 155
PP OUCIICL ea lnc Serctst ar 158
Sable ys. yest < ee 188
LENENUTCOLUS 23 vss 5% 160 |
Mhorelhiewsesre ae: 168, 215
Lophophonisy. ta... o. « 20
AISIOMIS' s.s.a.4s ures sass « 2h
[Gt DOCkiaes 758 5 2, «an wines oe 190
MNO ORVIAUIOE ode oat ot 163
WLLELCOLU Timer ane 163
EEL SULE PES ae ere ise oe 165
WMESOCKENES 2 A in 103
QUIISLECUBSY RO! tas ok 103
MESOCYEIOPS, 2 Po 282d 5. or
CRASSUS URC ioe cet: 61
IDV DOWUSIVE ea. a8 0: 62
ST UCUES Son so bis Jeti ok 63
OQUSOVETUST ere Asgoc 58
GUROMOLDES ss tle o9
WVIGQTONICOVE oo. 5 ao. 4 sein 173
HOGI Seeks as asr0 oud ae 173
LTE SUSTULSIS ee 2 sic ae 173
Monoculus quadricornis
ANONGIUS' 565 Gogo oobe mee
AUSCHSts 4 2 cals ate 65, 66
RUDENS! fae ances. 32, 33 |
WANICISE cyte esis 40,
INalg (Co) eee rene che © ye ee 202
Myzoponttide@ 22... 1a
WAV COP ONULUS). -. ccrsete cee: 113
WIUMUSCNS) ola 6S oa ae 113
INEQDONLLUS 0.0 oc ee. 115

29.— Crustacea.

221

Page
QHEUIATIST Jos ace 115
OE ONO Se reno ee 4
atlantl Gaewee- seen one 7
CMAUEN GSK aetna deta 6
helgolandica s >... so.. &. 9
JI Mees ee era Sle 5, 207
DiaMeraes + Ge ae Gilet
PYOMeae. on ie. 22 as Sy 39
SLINLLES ean a Pe 8, 207
SOLILUFOSULISE eee 6 |
ORNORIDRE EAR aeons ks |
iihoninay soe ee eae 5 5)
(OL TATE? nae WOR ee teak Be Pea 190
DOGEGLIS I ie): cote are 191
COMMMKAM Reena ee ote 191
TILETULLL Cnet ey eee ea AAG
SUPLELUS ar een rs eee ee: 193
Pachyeyclops'), 02.2 ae 64
AMMDICOLIUS! Sari 63
DISEASE Peer 67
SEBRALUS OS SOT 65
Pachivsomla ys oats ded: wwe: 190
ParGrtOrroeus...c 06. 135
ARCUECUS= ec A? am ho 136
Richandieer asc. o. ealoy, heayv
EON ROUAVOME! 65656550006 207
DEO Cae Ws: een sevens 208
jOG0 Va roe bee pee ene ae 209
W Rlatycheiront..1. pst 145, 146
PTO VOSCLOD Sra. eae onke 76
OPUS RR an ee 80
UL ORIQUEIS ey ee 81
DRGQICKOULNS «Gt Aue ned + 78
FE CUOSLOULG: a eee 142
Pseudanthessius ....... 166
GQ SSUTDULUS ie eee eee 170
QUID ULIS ane reer ate 214
FLTO OUTS See oat Pacer ere 167

| Sapphirina

LDCR Beis SA hs oe
SAUUO BEL se eriers ate.
Pseudolubbockia
Pseudomolgus
dilatatus
LEPLOSEYLISY, «2. 2 een
Pterinopsyllus
egregius
illustris
insignis
Picropontitis.ce. saree
Ratatat: gee tar, see
Rhinomolgus
QHOMALUS P5503. see
RAYACHOMYVZOR. Os) 2.0 ok
PAL CO Phe eer et eRe
purpurocinctum
FUOTOOULLALUMN I)...
Sabelliphilus ees: s..:..
CLONLAUUS ate es 2s ..
Lenekarbincsates 'y Lenin
Sarsii

Sapphirinide
SCOLOGHE TES -rescin aoe
CLOMEMUUSP aan ete
longitunca. 2.2...
Scottomyzon
gibberum
Scribellate, Aan sacri
Siphonostoma ss.
Solenostoma
scutatum
Thersites
Thersitina
Thorellia
lI nnn od dino oc 24,

LIST OF PEAMES:

(With corrections).

The following are the chief signs on the figures, with their signification:

& female; ~ male; C. cephalon; R. rostrum; 7. tail; gen. reg. genital region; F. furca
or caudal rami; a! anterior antenna; a? posterior antenna; or. area oral area; S. siphonal tube;
M. mandible; Mp. mandibular palp; m. maxilla; mp.! anterior maxilliped; mp. posterior maxil-
liped; p!—p?. legs of Ist to Sth pairs.

Pi
Oithona spinirostris, Claus.

Pu
Oithona spinirostris (continued).

Piel:
Oithona similis, Claus (see p. 207).

BibelV
Cyclopina gracilis, Claus.

PEL.
Cyclopina longicornis, Boeck.

PSV

Cyclopina Schneideri, Scott (see p. 209).

Pl. VII.
Cyclopina elegans, Scott.

PIP Vill.
Cyclopinella tumidula, G. O. Sars.

BISA
Cyclopetta difficilis, G. O. Sars.

Pl. X.
Pterinopsyllus insignis, Brady.

Ribekt
Pterinopsyllus insignis (male).

| PIES
Euryte longicauda, Philippi.
Pl XU.
Euryte robusta, Giesbrecht.
PUI:
Euryte curticornis, G. O. Sars.
BE Qe
Halicyclops magniceps (Lilljeborg).
Pip XVI
Cyclops pictus, Koch (see p. 211).
Pl. XVII.
Cyclops abyssorum, G. O. Sars.
Pl. XVIII.
Cyclops lacustris, G. O. Sars.
Pl. XIX:
Cyclops scutifer, G. O. Sars.
Bio
Cyclops vicinus, Ujanin.
Pl. XXI.

_ Cyclops insignis, Claus.

Pl. XXII.
Cyclops vulgaris, Koch.

Pl. XXIII.
Cyclops gigas, Claus.

Pl. XXIV.
Cyclops capillatus, G. O. Sars.

Pl. XXV.
Cyclops lucidulus, Koch.

Pl. XXVI.
Cyclops robustus, G. O. Sars.

Pl. XXVII.
Cyclops pulchellus, Koch.

Pl. XXVIII.
Cyclops bisetosus, Rehberg.

Pl. XXIX.
Cyclops crassicaudis, G. O. Sars.

Pl. XXX.
Cyclops langvidus, G. O. Sars.

RIZZEXXT:
Cyclops diaphanus, Fischer.

Pl. XXXII.
Cyclops abyssicola, Lilljeborg.

Pl. XXXIII.
Cyclops varicans, G. O. Sars.

Pl. XXXIV.
Cyclops bicolor, G. O. Sars.

Pl. XXXV.
Mesocyclops obsoletus (Koch).

Pl. XXXVI.
Mesocyclops oithonoides, G. O. Sars.

Pl. XXXVII.
Mesocyclops crassus (Fischer).

Pl. XXXVIII.
Mesocyclops Dybowskyi (Lande).

Pl. XXXIX.
Mesocyclops gracilis (Lilljeborg).

Pie RL,
Pachycyclops signatus (Koch).

ALO. GAG
Pachycyclops bistriatus (Koch).

Pl. XLII.
Pachycyclops annulicornis (Koch).

Pl XL:
Leptocyclops agilis (Koch).

Pl. XLIV.
Leptocyclops speratus (Lilljeborg).

PISXDY.
Leptocyclops Lilljeborgi, G. O. Sars.

Pl XLVI.

_ Leptocyclops macruroides (Lilljeborg).

Bis XLVI
Leptocyclops macrurus, G. O. Sars.

Pl. XLVIII.
Platycyclops phaleratus (Koch).

Pl. XLIX.
Platycyclops affinis, G. O. Sars.

Pig:
Platycyclops fimbriatus (Fischer).

JPA a) le
Ascomyzon asterocheres (Boeck).

Age lwlll
Ascomyzon asterocheres (continued).

Pl. LIII.
Ascomyzon Lilljeborgi, Thorell.

Pls LIVE
Ascomyzon Boecki (Brady).

Pl. LV.
Ascomyzon simulans, Scott.

PEE
Ascomyzon latum (Brady).

PieVil

_ Ascomyzon parvum (Giesbrecht).

Pl. LVIII.

| Echinocheres violaceus, Claus.

Pin Lixe
Dermatomyzon nigripes (Brady).

PSE.
Dermatomyzon nigripes (continued).

Pix

| Rhynchomyzon purpurocinctum (Scott).

PL xe

Rhynchomyzon rubrovittatum, G. O. Sars,

oo

PIeEXam: | Pl. LXXXIIL
Collocheres gracilicauda (Brady). | Lichomolgus albens, Thorell.
Pi EXIV. | Pl. LXXXIV.
Mesocheres anglicus, Norm. & Scott. | Lichomolgus forficula, Thorell.
Pl. LXV. | Pl. LXXXV.
Leptomyzon elegans (A. Scott). Lichomolgus marginatus, Thorell.
Pl. LXV. | Pl. LXXXVI.
Scottocheres elongatus (Scott). Lichomolgus furcillatus, Thorell.
RISEXVIE | Pl. LXXXVIL.
Acontiophorus scutatus, Brady. | Lichomolgus Canui, G. O. Sars.
Pl. LXVIIL | Pl. LXXXVIIL.
Myzopontius pungens, Giesbrecht. | Lichomolgus Poucheti, Canu.
Pl. LXIX. | Pl. LXXXIX.
Neopontius angularis, Scott. | Lichomolgus tenuifurcatus, G. O. Sars.
Pl. LXX. | PIXE
Dyspontius striatus, Thorell. _ Lichomolgus agilis (Leydig).
Pl. LXXI. | Pl. XCI.
Cryptopontius brevifurcatus, Giesbrecht. Pseudanthessius gracilis, Claus.
Pl. LXXII. | 12 ae. COLE
Arctopontius expansus, G. O. Sars. Pseudanthessius liber (Brady).
Pl. LXXIII. Pl. XCIII.
Bradypontius magniceps (Brady). Pseudanthessius assimilis, G. O. Sars.
Pl. LXXIV. PE XCIV:
Bradypontius papillatus (Scott). Pseudanthessius Sauvagei, Canu.
Pl. LXXV. PLAXGYV:
Bradypontius major, G. O. Sars. _ Macrocheiron fucicolum, Brady.
PIM EXXVI. PE XCVE
Bradypontius caudatus, G. O. Sars. Macrocheiron hirsutipes (Scott).
Pl. LXXVII. Pl. XCVII.
Cribropontius Normani (Brady). | Modiolicola insignis, Auriv.
Pl. LXXVIIL | Pl. XCVIIL.
Artotrogus orbicularis, Boeck. _ Hermannella valida, G. O. Sars.
Pl. LXXIX. | PPX
Parartotrogus arcticus, Scott. _ Hermannella parva, Norm. & Scott.
Pl. LXXX. | PG
Cancerilla tubulata, Dalyell. _ Hermannella prehensilis, G. O. Sars.
Pl. LXXXI. | PE GE
Hemicyclops purpureus, Boeck. Hermannella finmarchica, Scott.
Pl. LXXXII. | PIScik

Hippomolgus furcifer, G. O. Sars. | Hermannella tenuicaudis, G. O. Sars,

PE eit

Pseudomolgus leptostylis, G. O. Sars.

PEL GIV:
Pseudomolgus dilatatus, G. O. Sars.

PIPCVe
Rhinomolgus anomalus, G. O. Sars.
Rise:

Rhinomolgus anomalus (continued).

PIS GVil.
Sabelliphilus elongatus, M. Sars.

Pie eGVialle
Oncea borealis, G. O. Sars

PL; ODS
1. Oncea similis, G. O. Sars.

2. Coryceus anglicus, Lubb. (male).

BCs:
Coryceus anglicus, Lubb. (female).

225

Pin eX
| Ergasilus Sieboldi, Nordman.

Pi Ex
Conchocheres malleolatus, G. O. Sars.

PI Cx
Eunicicola Clausi, Kurz.

PLSCXIV.
Paroithona parvula, Farran.

PL CX:
1. Cyclopina euacantha, G. O. Sars.
Ds == pygmea, G. O. Sars.

Pl CXVI-
Scottomyzon gibberum (Scott).

Pl. CXVII.
Pseudanthessius dubius, G. O. Sars.

Pl CXVilh.
1. Lichomolgella pusilla, G. O. Sars.
2. Oncea minuta Giesbrecht.

ae

~

ul F =

AN ACCOUNT

OF TH

NORWAY

ene CO) NT

OF THE

ie St ACE

OF

NORWAY

WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES
BY

OS Ages

PROFESSOR OF ZOOLOGY AT THE UNIVERSITY OF CHRISTIANIA

VOL. Vi

COPE POA

CYCLOPOIDA
WITH 118 AUTOTYPIC PLATES

BERGEN
PUBLISHED BY THE BERGEN MUSEUM

SOLD BY
ALB, CAMMERMEYERS FORLAG, CHRISTIANIA
1918

BERGEN. A/S JOHN GRIEGS BOKTRYKKERI

PREFACE.

In concluding this Volume, I wish to observe that I am far from
claiming it to give any exhaustive account of the group treated off. Especially
as regards the semiparasitic forms belonging to the sections Siphonostoma and
Poecilostoma, there is certainly still much to do, and I have no doubt that,
on a closer and more methodical investigation of these interesting forms, many
new species will be added to those here described, the greater number of
which have been met with only quite accidentally in isolated specimens detached
from their hosts. Yet I hope that this Volume will be useful as comprehending
what is as yet known about this part of our Fauna.

As to the plates accompanying the present Volume, they are, as will
be seen, reproduced in quite a different manner from those in the preceding
Volumes, where the autographic method has been applied throughout. This
latter method may indeed give very good results, as seen from some of the
earlier Volumes of the present work. But the method involves some danger
for the clearness of the drawings, if not the outmost care is taken in their
transfer on the stone. I have been very sorry to see that several of the plates
accompanying the last (5th) Volume, for want of an habile and experienced
printer, have been less satisfactorily reproduced, and | therefore have thought
it right to abandon this method altogether and to chose another method, the
phototypic one, which, though somewhat more costy, will better ensure the
perfect reproduction of my drawings.

By the elaboration of the present Volume I have been assisted by the
same gentleman who did it in the case of the preceding Volume, and my
hearty thanks are here again paid to them for their kindness. I also is much
indebted to Prof. Wirén of the Upsala University and to Mr. G. P. Farran,
Dublin, lor kindly sending me specimens for examination. My best thanks are
moreover due to Mr. A. Kjaer for kindly having given me an opportunity of

ma

examining the bottom-residue of some large collecting bottles for search of
semiparasitic forms. Several interesting species of both siphonostomous and
poecilostomous Cyclopoida have thereby been secured and submitted to a
closer investigation. Finally | beg to thank the direction of the Bergen Museum
for the readiness with which it has admitted the increased expenses by the
altered reproduction of the plates, and for the interest it has shown in the
continued publication of my work.

G. O. Sars.

PRINCIPAL WORKS ON CYCLOPOIDA.

Aurivillius, C. W. S. Bidrag til Kannedomen om Krustaceer, som lelva hos

Baird, W.
Boeck, A.

Gann. JE.

Glagisauc.

Wana J. D:
arran, G.2P:

Mollusker och Tunicater. Stokh. 1883.

Natural History of British Entomostraca. 1850.

Tvende nye parasitiske Krebsdyr. Forh. Chr. Vid. Selsk. 1859.
Oversigt over de ved Norges Kyster iagttagne Copepoder hen-
herende til Calanidernes, Cyclopidernes og Harpacticidernes
Familier. Forh. Chr. Vid. Selsk. 1864.

Nye Slegter og Arter af Saltvandscopepoder; ibid. 1870.
Monograph of British Copepoda, Vol. Ill. 1880.

Report on the Copepoda of the Challenger Expedition. 1883.
Revision of the British species of Fresh-water Cyclopide and
Calanide. Nat. Hist. Trans. Northumb. & Durham. Vol. XI.
1891.

Several other papers inserted in various English Journals.

Les Hersiliide, famille nouvelle de Copépodes commensaux.
Contrib. 4 l’etude de la Fauna marine de Wimereux. V. 1898.
Les Copépodes de Boulonais 1892.

Die freilebenden Copepoden. 1862.

Die Copepoden-Fauna von Nizza. 1866.

Ueber neue oder wenig bekannte halbparasitische Copepoden.
Arch. Zool. Inst. Wien. Vol. VIII. 1889.

Crustacea of the United States Expl. Exped. 1855.

Second Report on the Copepoda of the Irish Atlantic-Slope.
Fisheries Ireland Sci. Invest. 1908.

On Copepoda of the genera Oithona and Paroithona. Proc.
Zool. Soc. London. 1913.

Fischer, S.

Giesbrecht, W.

FLEFFICRR AGL.
Jurine, L.
Koch. Gale
Kure W-
Lande, A.
Lilljeborg, W.

Miiller, O. F.
Nordman, A.

Norman, A. M.

Philippi, A.
Rehberg, H.
Richard, J.

Sars 1G: ‘O:

Vill

Beitrage zur Kenntniss der in der Umgegend von St. Peters-
burg sich findenden Cyclopiden. Bull. Soc. Imp. Moscou,
Vol. XXIV & XXVI. 1851.

Die freilebenden Copepoden der Kieler Fohrde. 1882.
Fauna & Flora des Golies von Neapel. Pelagische Copepoden.
1892.

Asterocheriden. 1892.

Die littoralen Cyclopiden des Golfes von Neapel. Mitth. Zool.
Stat. Neapel. 1900.

Synopsis of the Entomostraca of Minnesota. 1895.

Histoire des Monocles. 1820.

Deutschlands Crustaceen, Myriapoden und Arachniden. 1835
—A4l,

Eunicicola Clausi, ein neuer Anneliden—Parasit. Sitzb. Akad.
d2 Wiss. "Wien. bd’ Weve Terr

Materialy do Fauny Scorupiakow Widlonogish, Copepoda. 1890.
De Crustaceis ex ordinibus tribus in Scania occurrentibus. 1853.
Synopsis specierum Cyclopis Suecia. Kgl. Vet. Akad. Handl.
Vole 35. 19015

Entomostraca. 1785.

Mikrographische Beitrage zur Naturgeschichte wirbelloser Thiere.
1832.

& Scott, T. Notes on the Nat. Hist. of East Finmark. Ann.
Mag. Nat: Hist. ser7. Vol. XIF 1903!

Crustacea of Devon & Cornwall. 1906.

Beobachtungen iiber die Copepoden des Mittelmeeres. Wiegm.
Arch. 1848.

Beitrag zur Kenntniss der freilebenden Siisswasser-Copepoden.
Abh. Verein zu Bremen, Vol. VI. 1880.

Liste des Cladocéres et des Copépodes d’eau douce observés
en France. ‘Bull. Soc. Zool. France? Vole ay stee7-
Oversigt af de indenlandske Ferskvands-Copepoder. Forh.
Wide selsk “Chr? 1862:

On the Crustacean Fauna of Central Asia. Part III. Copepoda
and Ostracoda. 1904.

Zool. Results of the 3rd Tanganyika Expedition conducted by
Dr. W. A. Cunnington. Copepoda. 1909.

IX

Sars,.a. 0: Liste systématique des Cyclopoidés, Harpacticoidés et Monstril-
loidés receuillis pendant les campagnes de S. A. S. le Prince
Albert de Monaco, avec descriptions et figures des especes *
nouvelles. Bull. Inst. océanogr. No. 323. 1916.
Sars, M. Beskrivelse af 4 nye parasitiske Copepoder. Forh. Vid. Selsk.
Chir. 1862:
Schmeil, O. Deutschlands freilebenden Siisswasser Copepoden. Vol. 1. Cyc-
lopide. 1892.
Scott, A. Descriptions and Notes on some new and rare Copepoda from
Liverpool Bay. Rep. Lancashire Sea-Fisheries Laboratory. 1896.
a Report on the Pearl Oyster Fisheries of the Gulf of Mannar.
Copepoda. 1903.
— Copepoda of the Siboga Expedition. 1909.
Scott, T. Report on Entomostraca from the Gulf of Guinea. Trans. Lin. Soc.
London. Vol. VI. 1894.
= Several other papers inserted partly in Ann. Rep. of the Fishery
Board for Scotland, partly in Ann. Mag. Nat. Hist.
Thompson, I. C. Revised Report on the Copepoda of Liverpool Bay. Trans.
Liverpool Biol. Soc. Vol. VII. 1898.
Thorell, T. Bidrag til Kannedomen om Crustaceer som lefva i Arter af
Sl. Ascidia. Kgl. Vet. Akad. Handl. Vol. III. 1860.
Uljanin, W. N. Crustacea in Exp. Turkest. ab A. Fedtschenko coll. 1875.

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SYSTEMATIC LIST

OF THE SPECIES DESCRIBED IN THE PRESENT VOLUME.

Gnathostoma.

Oithonide.

Oithona, Baird.
spinirostris, Claus.
similis, Claus.

Paroithona, Faran.
parvula, Farran.

Cyclopinide.

Cyclopina, Claus.
gracilis, Claus.
longicornis, Boeck.
Sehneideri, Scott.
elegans, Scott.
euacantha, G. O. Sars.
pygmea, G. O. Sars.

Cyclopinella, G. O. Sars.

Sa tumidua. G.-O. Sats.

Cyclopetta, G. O. Sars.
difficilis, G. O. Sars.

Pterinopsyllus, Brady.
insignis, Brady.

Cyclopide.

Cyclops, Miiller.
pictus, Koch.

abyssorum, G. O. Sars.

lacustris, G. O. Sars.
scutifer, G. QO. Sars.
vicinus, Uljanin.
insignis, Claus.
vulgaris, Koch.

gigas, Claus.
capillatus, G. O. Sars.
lucidulus, Koch,
robustus, G. O. Sars.
pulchellus, Koch.
bisetosus, Rehberg.
crassicaudis, G. O. Sars.
langvidus, G. O. Sars.
diaphanus, Fischer.
abyssicola, Lilljeborg.
varicans, G. O. Sars.
bicolor, G. O. Sars.

Mesocyclops, G. O. Sars.

obsoletus, Koch.
oithonoides, G. O. Sars.
crassus, Fischer.
Dybowskyi, Lande.
gracilis, Lilljeborg.

| Pachycyclops, G. O. Sars.

signatus, Koch.
bistriatus, Koch.
annulicornis, Koch.

Leptocyclops, G. O. Sars.

agilis, Koch.
speratus, Lilljeborg.

Lilljeborgi, G. O. Sars.
macruroides, Lilljeborg.
macrurus, Gh. Omsats:
Platycyclops, G. O. Sars.
phaleratus, Koch.
ajjinis, G: ©: Sars.
fimbriatus, Fischer.

Siphonostoma.

Ascomyzontide.

Ascomyzon, Thorell.
asterocheres, Boeck.
Lilljeborgi, Thorell.
Boecki, Brady.
simulans, Scott.
latum, Brady.
parvum, Giesbrecht.

Echinocheres, Claus.
violaceus, Claus.

Dermatomyzon, Claus.
nigripes, Brady.

Rhynchomyzon, Giesbr.
purpurocinctum, Scott.

rubrovittatum, G. O. Sars.

Collocheres, Canu.
gracilicauda, Brady.
Mesocheres, Norm. & Scott.

anglicus, Norm. & Scott.
Leptomyzon, G. O. Sars.
elegans, A. Scott.
Scottocheres, Giesbrecht.
elongatus, Scott.
Scottomyzon, Giesbr.
gibberum, Scott.

Acontiophoride.

Acontiophorus, Brady.
scutatus, Brady.

XI

Myzopontiide.

Myzopontius, Giesbr.
pungens, Giesbr.

Neopontius, Scott.
angularis, Scott.

Dyspontiide.

Dyspontius, Thorell.
striatus, Thorell.
Cryptopontius, Giesbr.
brevifurcatus, Giesbr.
Arctopontius, G. O. Sars.
expansus, G. O. Sars.
Bradypontius, Giesbr.
magniceps, Brady.
papillatus, Scott.
major, G. O. Sars.
caudatus, G. O. Sars.
Cribropontius, Giesbrecht.
Normani, Brady.

Artotrogidez.

Artotrogus, Boeck.
orbicularis, Boeck.

Cancerillide.

Parartotrogus, Scott.
arcticus, Scott.

Cancerilla, Dalyell.
tubulata, Dalyell.

Poecilostoma.

Clausidiide.

Hemicyclops, Boeck.
purpureus, Boeck.
Hippomolgus, G. O. Sars.

furcifer, G. QO. Sars,

Lichomolgide.

Lichomolgus, Thorell.
albens, Thorell.
marginatus, Thorell.
forficula, Thorell.
furcillata, Thorell.
Canui,G. -O.. Sats:
Poucheti, Canu.
tenuifurcatus, G. O. Sars.
agilis, Leydig.

Macrocheiron, Brady.
fucicolum, Brady.
hirsutipes, Scott.

Pseudanthessius, Claus.
gracilis, Claus.
liber, Brady.
assimilis. "G, Os. Sars.
Sauvagei, Canu.
aupius, GO; Sats.

Lichomolgella, G. O. Sars.
pasila. G. ©; Sais.

Modiolicola, Auriv.
insignis, Auriv.

Hermannella, Canu.
dalida, “G: QO. Sats.
parva, Norm. & Scott.
prehensilis, G. O. Sars.
finmarchica, Scott.
tenuicaudis, G. O. Sars.

Pseudomolgus, G. O. Sars.
leptostylis, G. O. Sars.
dilatatus, G. ©; Sats.

Xill

Rhinomolgus, G. O. Sars.
anomalus, G. O. Sars.

Sabelliphilus, M. Sars.
elongatus, M. Sars.

Onceide.

Onceza, Philippi.
borealis, G. O. Sars.
similis, Go-O. Sats:
minuta, Giesbr.

Coryceide.
Coryceeus, Dana.
anglicus, Lubb.
Ergasilide.
Ergasilus, Nordman.
Sieboldi, Nordm.
Clausiide.
Conchocheres, G. O. Sars.
malleolatus, G. O. Sars.

Eunicicolide.

Eunicicola, Kurz.
Clausi, Kurz.

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XCVII

Copepoda
Cyclopoida Pl.

Lichomolgide

RY PR ph ce stnecratereceeevet met =

G. O. Sars, del.

is, Aurivillius

insignis

Modiolicola

2

*
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Mead ated wi
a Lame 4

re

aie

Pl. XCVIII

Copepoda
Cyclopoida

Lichomolgide

G. O. Sars, del.

Hermannella valida, G. O. Sars

Copepoda

Lichomolgidae Cyclopoida Pl. XCIX

sae at TTS a a
ees Wee

G. O. Sars, del.

Hermannella parva, Norm. & Scott

Copepoda

fle

Cyclopoida

Lichomolgidz

Se ee |
Kies ?

i

oy

G. O. Sars, del.

Hermannella prehensilis, G. O. Sars

Piel

ee xs
y
xe Oe 3
’ fy < Vina
\ \ ~
\ c
\\ ,

‘

Copepoda
Cyclopoida

Lichomolgidz

G. O. Sars, del.

Hermannella finmarchica, Scott

Copepoda

Lichomolgidz Cyclopoida

=
LSS,

My
i Wi,
N }
te
Wi
Nay
x
| eo.
SS

G. O. Sars, del.

Hermanella tenuicaudis, G. O. Sars

the
Bix

Pl. Cill

Copepoda
Cyclopoida

Lichomolgide

a)
a

~~

awe

W

\

A WS
eS

Se

i
ARS SSH

Cao
Sy
LGE if

G. O. Sars, del.

Pseudomolgus leptostylis, G. O. Sars

Copepoda

CIV

Cuclopoida Pl.

Lichomolgide

G. O. Sars, del.

Pseudomolgus dilatatus, G. O. Sars

PINCY.

Copepoda
Cyclopoida

Lichomolgidz

Sater
ym TRE

oe CAL ee
SET ES BOT RS
PT ea ;
tens : j

’ j
}
=e,
a

G. O. Sars del.

Rhinomolgus anomalus, G. O. Sars

‘w2 ©,
odd ;
the *

Copepoda

Pl. CVI

Cyclopoida

Lichomolgidez

G. O. Sars, del.

Rhinomolgus anomalus, G. O. Sars

(continued)

Pl. CVII

Cyclopoida

Copepoda

Lichomolgide

f
RHETT Oey
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Sabelliphilus elongatus, M. Sars

G. O. Sars, del.

Cyclopoida Pi. CVIII

Copepoda

Onceide

1a ne ie y
esac ae

if

Fb Sig lentineae
/ a POT ee ceca
SSS 5 SOc eat Bea ee pn he EN
Bias eae sass
i Hy end AIOE,
SPN PS ele
ae

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aes Soe
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a
foes

Oncea borealis. G. O. Sars

G. O. Sars, del.

Copepoda

CIX

Pir

Cyclopoida

Onceide —Coryceride

ed

WE = =

KX aN Sse ~~

BNNs
«

—

a Sa

G O. Sars, del.

Oncza similis, G. O. Sars
2. Corycezus anglicus, Lubbock +

Ale

Copepoda

Pine x

Cyclopoida

Coryceide

a
gee

G. O. Sars, del.

Corycezus anglicus, Lubbock 9?

Copepoda

_ Ergasilidae Cyclopoida Pl. CXI

G. O. Sars, del.

Ergasilus Sieboldi, Nordm.

CXi

Copepoda
Cyclopoida Pl.

Clausiide

Conchocheres malleolatus, G. O. Sars

G. O. Sars, del.

eS ae ee ie eee Tee

Copepoda

Eunicicolidee Cyclopoida Pl. CXIII

G. O. Sars, del.

Eunicicola Clausi, Kurz

Pl. CXIV

Copepoda
Cyclopoida

Oithonide

ee eae

SO Be
Bs ae ;
é a a ree Ro aac
A IP arene aS

cmt

Ce aes oh
Se

nee
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SEN eee OLE, id | nee
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a 3s) See AA = ee:
/ A: Riser } tk
SiRasmee Sen ae
fof rf or Wee
yaa. SE
ao if

G. O. Sars, del.

Paroithona parvula, Farran

CXV

PI.

Copepoda
Cyclopoida

Cyclopinide

G. O. Sars, del.

Cyclopina euacantha, G. O. Sars

ile

pugmea, G. O. Sars

Copepoda

CXVI

Pl.

Cyclopoida

Ascomyzontide

- ey \

t

—.

= Ses

G. O. Sars, del.

Scottomyzon gibberum, (Scott)

Copepoda

CXVII

Cyclopoida Pl.

Lichomolgidz

G. O. Sars, del.

Pseudanthessius dubius, G. O. Sars

0
a EER A

Copepoda

Lichomolgides— Oncaeidee Cyclopoida

Pl. CXVIII

ee

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\

7 y rt
de NK A yA
a wn h\s
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y HH

Sa DY,

seas ae

1 bs
+ \ bs
bea
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.
+
/
4 i
A
i
ay
Hig
}
i | }

G. O. Sars, del.

1. Lichomolgella pusilla, G. O. Sars
2. Oncea minuta, Giesbr.

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