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x 74

AN ACCOUNT

OF THE

GCRUSTAGEA

OF
WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

BY

G. O. SARS

VOL. IV

COPEPODA
CALANOIDA

PART I & Il

CALANIDA, EUCALANIDA, PARACALANIDA,
PSEUDOCALANIDA, ATIDEIDZ: (part)

WITH 16 AUTOGRAPHIC PLATES

BERGEN
PUBLISHED BY THE BERGEN MUSEUM
SOLD BY
ALB. CAMMERMEYER’S KORLAG, CHRISTIANIA
1901 °=

INTRODUCTION.

Or all the orders of Crustacea, that of the Copepoda is perhaps the most
extensive one, comprising, as it does, an immense number of forms, which, both
as to structure and habits, exhibit quite wonderful variation. Some of them
lead a free existence as pelagic organisms, and are comparatively highly orga-
nized; some are more sedentary in habits, being restricted to the bottom, or are
partly semiparasitic; and a considerable number are true parasites, becoming so
much degenerated in the adult state, that they sometimes even hardly admit
of being recognized as Crustacea, but look more like worms. It is easy to
believe that the parasitic forms have originally descended from free-living forms ;
and indeed, the semiparasitic Copepoda form a well-marked transition between
the 2 groups. In consequence of this, the most primitive characters must be
sought for not among the parasites, but among the free-living forms. During
the development, which is always at true metamorphosis, all the Copepoda
pass through some free-living stages, the earliest of which is the well-known,
so-called Nauplian stage, also found in some other Crustacea, for instance the
Phyllopoda and the Luphausude. This very primitive stage is characterised by
a rounded or oval, unsegmented body, which only carries 3 pairs of movable
appendages, viz., the antennulze, the antenne, and the mandibular legs, the mouth
being protected in front by a large flap-shaped lip. The segmentation of the
body takes place gradually in the succeeding stages, but never attains that
elaborate arrangement found in the higher Crustacea (the Malacostraca), and is
sometimes again wholly lost in the parasitic life. As is clearly shown by the
development of the Huphausiide, and by the structure of the Phyllocarida, one
of the chief divisions found in the higher Crustacea (Malacostraca), and often
constituting by far the greater part of the body, viz., the mesosome, never comes
to development in the Copepoda. On the other hand the posterior part of the
body is, as a rule, like that in the Phyllocarida, divided into 2 sharply defined

1 — Crustacea.

sections, the metasome and urosome, the former carrying the natatory legs,
evidently answering to the pleopoda in the Malacostraca, whereas the latter never
carries any true appendages, and is terminated by the so-called furca or caudal
rami. The division anterior to the metasome may more properly be termed
the cephalosome, though very often confluent with the Ist segment of the
metasome. It carries, as arule, 6 pairs of movable appendages, viz., the anterior
and posterior antennie, the mandibles, the maxillee, and 2 pairs of maxillipeds.
At about the middle of this division, below, the oral aperture occurs, in the
free-living forms bounded in front by a flap-shaped anterior lip and behind
by a bilobate posterior lip. These lips in some of the parasitic forms are pro-
longed into a sipho receiving the styliform masticatory parts of the mandibles.
A more or less pronounced reduction of the cephalic appendages may be observed
in the most degenerate parasites (Lerneoida); and even in one peculiar group of
free-living forms, the Monstrilloida, this reduction is so far advanced, that only
the anterior antenne are left, not even the slightest trace of either the posterior
antenne or any of the oral appendages being visible, at any rate in the adult state.

As to the classification of the Copepoda, the views of the several authors
differ considerably, according to the characters which have been selected as the
basis for the classification. The well-known classification of the Copepoda by
T. Thorell into 3 great divisions, Gnathostoma, Poecilostoma and Siphonostoma,
refers exclusively to the structure of the oral parts, and was at first much esteemed
by carcinologists. As, however, quite gradual transitions in the structure of the
oral parts between these 3 types have been found to exist, and moreover, by
accepting these groups, otherwise evidently nearly-allied forms would be sepa-
rated from each other in an unnatural manner, this classification cannot at present
be regarded as fully satisfactory. The establishment by Dr. Giesbrecht of the 2
great divisions, or sub-orders, Gymnoplea and Podoplea, is certainly more natural ;
but these divisions do not nearly suffice for the comprising of all the Copepoda, as
they apparently relate only to the pelagic form examined by that author. Nor, I
believe, can the recent subdivision of the Copepoda proposed by Dr. E. Canu,
according to the structure of the female genital openings, into the Monoporodelphia
and Diporodelphia, lay any claim to general acceptation. There are, I think, 7
distinct types among the Copepoda, which may indicate as many great divisions
or sub-orders. These types are represented by the following well-known genera:
Calanus, Harpacticus, Cyclops, Notodelphys, Monstrilla, Caligus and Lernea. In
accordance herewith, 7 divisions are adopted in the present work, viz., Calanoida,
Harpacticoida, Cyclopoida, Notodelphyoida, Monstrilloida, Caligoida and Lerneoida,

each comprising a number of distinct families, which may be referred to 2 or

more sections. The first-named division, which forms the subject of the present
Volume, answers to the sub-order Gymoplea of Dr. Giesbrecht, and comprises the
most highly organized Copepoda.

The free-living marine Copepoda of Norway have been partly studied by
the late A. Boeck, who, in the Transactions of the Christiania Scientific Society,
has given a preliminary account of the species observed by him. I have myself,
during a long series of years, given my attention both to the marine and freshi-
water forms of our country, and have long since published a synopsis of the latter.
Among foreign naturalists who have made these Crustacea the object of special
study, may be named the late Prof. C. Claus, to whom we are indebted for a rather
full account of the internal anatomy and development of Copepoda, and Prof. G.S.
Brady, whose monograph of the British free and semiparasitic Copepoda is especi-
ally valuable for the knowledge of the northern forms. More recently a standard-
work on these Crustacea has been published by Dr. W. Giesbrecht, forming one
of the admirable series of treatises edited by the Zoological Station of Naples.
This excellent work, which, however, only relates to the strictly pelagic forms,
comprises, besides Mediterranean species, also forms from all parts of the Oceans,
and thus gives by far the most complete account of the species of this kind.
Both the descriptions and figures are far superior to any formerly given, and it
is only to be regretted that the arrangement of the figures on the plates is such,
that no little trouble is entailed to find at once the details relating to each
species. Though I do not venture to think that the modest account here given will
in any way compete with Dr. Giesbrecht’s splendid work, I hope that its arrange-
ment may be found somewhat more convenient by students for an easy deter-

mination of the northern species.

CALANOIDA.

The chief characters of this great division have been well pointed out by
Dr. Giesbrecht, and consist in the firm conjunction of the last pedigerous segment
with the preceeding one, with which it is not infrequently even wholly coalesced,
whereas in most other Copepoda this segment forms a very movable articulation
with the former, and is firmly connected with the Ist segment of the urosome,
thus giving it the appearance of belonging more properly to that section of the
body. In all the forms the anterior division of the body, comprising the cepha-
losome and metasome, is much broader than the posterior (urosome), which is
abruptly narrowed and very movably connected with the former. The female
genital openings occur generally close together on the ventral face of the Ist
caudal segment, whereas in the male only a single such opening is found lying
asymmetrically, generally on the left side.

As to the several appendages, the anterior antennze are as a rule much
elongated, sometimes of the very same appearance in the two sexes, but more
generally transformed in the male, either by a reduction of the number of articula-
tions combined with a much more abundant supply of the peculiar sensory appen-
dages named by Dr. Giesbrecht “aesthetascs”, or by a geniculated structure of
one, generally the right, antenna. The posterior antenne are always biramous,
with the inner ramus (endopodite) biarticulate, the outer (exopodite) multiarticulate,
though the latter, in some cases, is much reduced in size. The mandibles generally
have the masticatory part exceedingly dentate, and are provided with a well-
developed biramous palp, which, like the posterior antenn, is subservient to
locomotion. The maxille generally exhibit a rather complicated structure, though
the same chief parts as in the 2 preceding pairs of appendages may easily be
demonstrated, with the addition of 3 setiferous lobes, the generally large vibratory
plate outside the basal part, and the 2 much smaller appendicular lobes occur-

ring close together inside between the basal part and the palp. The 2 pairs of

maxillipeds always form simple stems furnished with procurved sete or claws, and
on them may be easily distinguished a basal and a terminal part, the former
generally biarticulate, the latter multiarticulate. As a rule, the posterior max-
illipeds are more slender than the anterior; but in some cases this pair is much
reduced in size, whereas the anterior pair may be very powerfully developed.
Of legs generally 5 pairs occur, the 4 anterior of which are always natatory
and biramous, whereas the last pair are only exceptionally of that character,
but in the female are more generally much reduced, not infrequently even wholly
absent, and in the male are transformed into prehensile organs, by the aid of
which the spermatophores are grasped and transferred to the female. The normal
number of caudal setz is 5 on each ramus; but this number is sometimes
reduced to 4 or even to 3. In every case, in addition to the true caudal sete,
a slender bristle may be observed on the inner corner of each ramus, gener-
ally extending dorsally, more rarely ventrally. The ovisac, when present, is
always simple, more or less flattened in form, and attached to the ventral face
of the genital segment.

As to the internal organisation, the Calanoida are prominently distinguished
by the presence of a well-developed heart occurring dorsally at the limit between
the Ist and 2nd pedigercus segments. The male generative organ is asymmetrical,
the efferent duct being located on one side, generally the left. The asymme-
trical structure of the last pair of prehensile legs is apparently in accordance
with this circumstance.

By far the greater number of the Calanoida are marine; but there are also
several forms peculiar to fresh or brackish water, especially of the families
Centropagide, Diaptomide and Temoride. In the Oceans some forms, especially
of the genus Calanus, often occur in immense shoals, forming the bulk of the
“Zooplankton”. These animals therefore are of great importance as fish-food, and
in some cases even form the chief nourishment of the great whales,

The exact subdivision of the Calonoida is connected with no small
difficulty, owing to the great variation in the leading characters. Dr. Gies-
brecht, in his beautiful work, has however tried to make such a subdivision. His
two primary sections, Amphascandria and Heterarthiandria, are very natural,
though I think that a 3rd such section ought to be added, comprising those forms
in which the anterior antenne are alike in both sexes. For this section I
propose to use the name Jsokerandria, applied by Dr. Giesbrecht also to a
section of the Cyclopoida. According to Dr. Giesbrecht’s classification the 1st
section only includes a single family, the Calanidw, whereas the 2nd com-

prises 3 families, viz., the Centropagide, Candacide and Pontellide. The 2 first

6

families are again divided into a great number of sub-families, whereas the 3rd
only includes a single such sub-family, and the 4th only 2. The disproportion of
this classification is very obvious. In my opinion the number of true families
accepted by Dr. Giesbrecht is much too small in proportion to the numerous
Calonoid genera established, and I have therefore felt justified in raising the several
sub-families to the rank of true families, though some of them, it is true, are
rather closely allied. I think that thus a more uniform and convenient arrange-
ment of the genera may be obtained.

As the very great majority of the Calanoida are pronouncedly pelagic
animals, often occurring in the open sea at a considerable distance from the coast,
the limits of the fauna-domain ought in this case to be considerably more ex-
tended than is generally allowed for the bottom-forms. I therefore refer to the
Norwegian fauna all forms that have been found anywhere in those parts of the
Ocean surrounding the Norwegian coast, viz.. the Skagerak, the North Sea, that
part of the North Atlantic generally termed the Norwegian Sea, and bounded on
the west by the Shetland Isles, Iceland and Jan Mayen, and on the east by
Spitsbergen and Bear Island, and finally the Barents Sea, which washes the
greater part of the Finmark coast. Indeed, any form that has been observed
even at the outer limits of these parts of the Ocean, may be assumed occasionally
also to occur in the immediate neighbourhood of the Norwegian coast.

Though the distribution of some Calanoid species has proved to be
extraordinarily wide, we must, I think, admit that several of the forms found
off the Norwegian coast are of true arctic origin, others peculiar to the North
Atlantic, and others again of still more southern rise; for it is very likely that
northern forms may occasionally be carried far away from their true home by
currents, and, vice versa, southern forms may be carried in the same manner
northwards, beyond the limits of their true domain. It may thus easily happen
that species of very different origin may be found in the very same tract of the
Ocean, though perhaps at different seasons of the year. In the great depths of
the Norwegian fjords, a peculiar Calanoid fauna was long ago proved to occur.
By the recent investigations of the plankton-organisms taken during Nansen’s Polar
Expedition, it has been ascertained by the present author that the greater number
of these peculiar deep-water Calanoids are of true arctic origin, the same species
occurring also in the Polar basin, often at the very surface of the sea. They
must accordingly be regarded as relict arctic forms, existing in the depths of
the fjords from ancient times (the glacial period), when the sea surrounding the

Norwegian coast still exhibited a purely arctic character.

Section 1.

Amphaseandria.

This section is chiefly characterised by the fact that both of the anterior
antenne: in the male are alike and only shghtly transformed, never exhibiting any
geniculate structure, but only differing from those in the female by a more or
less pronounced coalescence of some of the articulations, and in the much more
abundant supply of sensory appendages. In the greater number of genera the
adult male is moreover distinguished by a very conspicuous transformation of
the oral parts, some of which appear greatly reduced. In some cases also the
external appearance of the male is so very different from that of the female, that
it becomes rather difficult to recognise both as belonging to the same species.

All the Amphascandria, as yet known, are marine, and by far the greater
number lead a true pelagic life, though there are a few forms that seem to be
more restricted to the bottom, being as yet only found close to the ground
in moderate depths, e. g. the species of the genera Undinopsis, Bryaxis and
Pseudophaenna. On the other hand, some of the forms, e. g. Paracalanus parvus,
are almost constantly found at the very surface of the sea, and are often thrown
by the waves upon the shore, where they may be found in considerable numbers,
left in tidal pools.

The Norwegian forms belonging to this section may be referred to 8

different families, of which diagnoses are given below.

Fam. 1. Calanide.

Characters.—Cephalosome well defined, or coalescent with the 1st pediger-
ous segment; front carrying below 2 soft posteriorly curving tentacular filaments.
Last pedigerous segment not confluent with the preceding one, and having the
lateral corners but. slightly produced. Urosome not very slender, consisting in
female of 4, in male of 5 segments, caudal rami comparatively short, with the
normal number of sete. Eye simple, very small, subventral. Anterior antennz
in female long and slender, consisting of 25 articulations, which are supplied
anteriorly with comparatively short and uniform bristles; penultimate and ante-
penultimate articulations each having behind an unusually strong and densely
plumous seta extended straight backwards. Anterior antennz in male thickened
at the base, with some of the proximal articulations fused together and supplied
below with a restricted number of comparatively short sensory appendages.
Posterior antenne with the rami of about equal length. Oral parts of normal
structure, being but slightly transformed in male. Legs with both rami 3-articulate,
terminal joint of outer ramus with only 2 spines outside. 5th pair of legs in
female of a similar structure to that in the preceding pairs, in male more or
less transformed, left leg the stronger.

Remarks.—This family, answering to the subfamily Calanine of Dr.
Giesbrecht, is chiefly characterised by the structure of the 5th pair of legs,
which, at any rate in the female, are natatory and of a similar appearance to that
of the preceeding pairs. Moreover, the long and slender anterior antenne, with
the 2 remarkably developed subapical setze, furnish an easily recognizable character.
The family comprises as yet only 2 genera, viz., Calanus Leach, and Undina
Dana. These 2 genera, it is true, have been combined by Dr. Giesbrecht; but
I think that they ought more properly to be kept apart, as the structure of the
last pair of legs in the male differs conspicuously in the 2 genera. In the

northern seas only the first-named genus is represented.

Gen. 1. Calanus, Leach, 1816.

Syn: Cetochilus, Roussel de Vauzéme, Baird, Claus.

Generic Characters.—Body comparatively slender, with the anterior divi-

sion oblong subcylindric in form, and more than twice as long as the posterior.

a

Cephalosome generally well defined from the Ist pedigerous segment, and slightly
carinated dorsally in the male, frontal part obtuse, and more or less projecting
between the insertions of the anterior antenne. Lateral corners of last pedigerous
segment generally rounded off. Urosome symmetrical, with the genital segment
in female comparatively short and but slightly protuberant below. Caudal rami
well defined from the anal segment, and in male movably articulated to it, admit-
ting of being spread outwards, 2nd caudal seta (from within) longer than the
others. Anterior antenne generally longer than the body, and much more strongly
built in male than in female, with the first 2 articulations fused together into
a broad, somewhat flattened segment. Posterior antenne with the outer ramus
7-articulate. Posterior maxillipeds with the terminal part longer than either of
the basal joints, and 5-articulate, sete of the outer edge in male remarkably
developed and densely plumous. Legs comparatively slender, inner ramus well
developed, though considerably shorter than the outer, its 2nd joint (except in
last pair) having 2 natatory sete inside. Last pair of legs with the Ist basal
joint denticulate along the inner edge, but without the plumose seta present in
the other pairs; outer ramus in male without any natatory sete, and more strongly
developed on left side, though imperfectly prehensile; inner ramus in both legs
well developed, and resembling that in female.

Remarks.—In the restriction here adopted, this genus is chiefly charac-
terised by the imperfect prehensility of the last pair of legs in the male, this
pair still preserving its natatory character, whereas in the 2nd genus, Undina,
it is very much transformed, the left leg being quite enormously developed and
pronouncedly prehensile. Otherwise these 2 genera are closely related. The pre-
sent genus comprises several species, and seems to be represented in all parts
of the Oceans. To the Norwegian fauna belong 3 nearly-allied species, one of

which, however, has generally been confounded with the type species.

1. Calanus finmarchicus, (Gunnerus).
(Plt, 1 um)

Monoculus finmarchicus, Gunnerus, Acta Hafnia, Vol. X, p. 175, figs. 20—23.
Syn: Cetochilus septentrionalis, Goodsir.
» Calanus spitsbergensis, Kréyer Q.
59 — qvinqueannulatus, Kréyer &.

Specific Characters.—Female. Anterior division of body, seen dorsally,
oblong oval in form, greatest width equalling 1/; of the length and occurring
about in the middle, frontal part but slightly produced; seen laterally, somewhat
dilated anteriorly, with the frontal margin broadly rounded and forming, together

2 — Crustacea.

10

with the dorsal one, a perfectly even curve. Lateral corners of last pedigerous
segment slightly produced, but rounded at the tip. Urosome about half the length
of the metasome; caudal rami somewhat longer than the anal segment. Anterior
antennee, when reflexed, extending beyond the caudal rami by about the last 3
articulations.

Male.—Cephalosome more sharply defined behind than in female, forming
at the end dorsally a small gibbous projection, and distinctly carimated above,
frontal part somewhat more prominent; lateral corners of last pedigerous segment
less produced. Urosome rather slender, with the 2nd segment much the largest.
Subapical plumose setz of anterior antenn less developed than in female, and
somewhat uneqal in length. Last pair of legs with the outer rami not very
different in appearance, the left one, however, somewhat longer than the right,
with the terminal joint obpyriform in shape and nearly as long as the preceeding
joint, corresponding inner ramus reaching beyond the middle of the 2nd joint of
the outer one.

Colour.—Body pellucid, more or less tinged with light red, anterior
antenn often bright red.

Size.—Usual length of adult female about 4 mm., of male 3.60 mm.
Maximum length of arctic specimens 5 mm.

Remarks.—This is apparently the form at first recorded by Gunnerus as
Monoculus finmarchicus. It has, however, been confounded by most authors with
the succeeding nearly-allied species, from which, on a closer examination, 1t may
be easily distinguished in both sexes, chiefly by the more evenly rounded frontal
part, the longer caudal rami, and the less elongated outer ramus of the left last
leg in the male. It’also attains a considerably larger size than does the above-
mentioned species. The 2 supposed species described by Kréyer as Calanus
spitsbergensis and C. qvuinqueannulatus are unquestionably both referable to the
present species, the former being the female and the latter the male.

Occurrence.—Of all the marine Calanoids of Norway, this form is by far
the most common, occurring often in enormous shoals, and thus sometimes giving
the sea a conspicuously reddish hue. It is found everywhere in the open sea,
more frequently at the very surface, though at times it may also descend to
greater depths, or be carried by the waves and currents towards the shores or
into the bays and fjords. Off the Norwegian coast, I have met with it from
Vadso to Jederen (Tananger); but farther east it seems to be superseded by
the succeeding species. It moves rather rapidly, with abrupt bounds caused by
energetic strokes of the natatory legs. At times, however, it is seen quietly

suspended in the water, with the anterior antenne spread out to each side at right

it

angles to the body, or proceeding slowly by rapid vibrations of the posterior
antenne and the mandibular palps. The male is still more agile than the female,
and the motion effected by the posterior antenne and mandibular palps is more
energetic, in accordance with the somewhat stronger development of these appen-
dages and the pertaining muscles, being changed to a somewhat jerky leap
through the water. At some seasons male specimens are by no means rare,
though the female sex always preponderates considerably in number. This Calanoid
is eagerly devoured by some of our common food-fishes, for instance the herring
and the mackerel, and in some cases, as stated by Prof. Rob. Collett, forms almost
the exclusive nourishment of one of our great whales, Balenoptera borealis.
Distribution—The present species seems to be especially characteristic
of the arctic zone, occurring abundantly in almost all samples of plankton taken
in that part of the Ocean, from Greenland in the west to the Behring Islands in
the east. In the icy Polar basin crossed by Nansen, it occurred everywhere, and
often in great abundance, up to and beyond 85° of latitude. The former statements
about the extraordinarily wide distribution of the present species southwards,
cannot be regarded as reliable, owing to its having been confounded with the

succeeding species.

2. Calanus helgolandicus, (Claus).
(Pl. IV.)

Cetochilus helgolandicus, Claus, Die frei lebenden Copepoden, p. 171, Pl. XXVI, figs. 2—9.

Syn: Calanus finmarchicus, Brady, Giesbrecht etc. (not Gunnerus).

Specific Characters.—Female. Anterior division of body, seen dorsally,
narrow oblong in form, greatest width not attaining '/; of the length, frontal part
angularly produced between the insertions of the anterior antenne; seen laterally,
scarcely dilated at all anteriorly, frontal margin abruptly and narrowly curved.
Lateral corners of last pedigerous segment but very slightly produced and obtusely
rounded. Urosome exceeding half the length of the metasome, caudal rami rather
short, scarcely longer than the anal segment. Anterior antenne, when reflexed,
reaching beyond the caudal rami by about the last 2 articulations. J/ale resembling
that of the preceding species, but having the frontal part considerably more pro-
duced. Last pair of legs more asymmetrical, the outer ramus of left leg being
considerably elongated, with the terminal joint scarcely exceeding half the length
of the penultimate one, inner ramus extending but little beyond the 1st joint of

the outer ramus. Body in both sexes very pellucid, with a slight reddish pigment

ce

especially along the ventral side. Length of adult female but little exceeding 3 mm.,
of male 2.80 mm.

Remarks.—As above stated, this form has generally been confounded with
C. finmarchicus, to which species it certainly bears a very close resemblance. It
is, however, rather inferior in size, and, on a closer examination, may moreover
be easily distinguished by the somewhat more slender form of the body, the more
produced and narrowly rounded frontal part, the shorter caudal rami, and the
considerably more elongated outer ramus on the left leg of the last pair in the male.
The Cetochilus helgolandicus of Claus is unquestionably this species, and this is
also certainly the case with the form recorded by Brady from the Challenger
Expedition, and with that described by Dr. Giesbrecht from the Mediterranean.

Occurrence.—I have met with this species very frequently in the Christi-
ania Fjord, for instance at Drobak, as also in several other places on the southern
coast of Norway. I have no certain evidence of its occurrence farther north,
though in all probability it also extends for some distance along the western coast.

Distribution.—Its range is evidently a more southern one than that of
C. finmarchicus. It has been recorded from Heligoland by Claus, from the British
Isles by Brady, the western coast of France by Dr. Canu, the Mediterranean by
Dr. Giesbrecht, the Black Sea by W. Karawaien, and it is even said by Brady
to occur in the Southern Ocean, off New Zealand, though in this case a confusion

with a nearly allied species may perhaps be presumed to have taken place.

3. Calanus hyperboreus, Kroyer.
(Pl. V.)
Calanus hyperboreus, Kroyer, Gronlands Amphipoder, p. 84, Pl. IV, fig. 23.
Syn: Calanus magnus, Lubbock.

— finmarchicus, var. major, auctorum.

Specific Characters.—Female.—Anterior division of body very large, seen
dorsally oblong fusiform, greatest width about equalling 1/3 of the length, and
occurring in the middle, frontal part but slightly prominent and, seen laterally,
evenly rounded. Lateral corners of last pedigerous segment somewhat produced,
forming at the tip an acute angle. Urosome not nearly attaining half the length
of the metasome, caudal rami comparatively short, scarcely longer than the anal
segment. Anterior antenne, when reflexed, reaching beyond the caudal rami by
about the last 3 articulations. Male resembling that of the 2 preceding species,
but having the frontal part less prominent, and the lateral corners of last pedige-
rous segment angularly produced, as in female. Last pair of legs but slightly
asymmetrical, outer ramus of left leg scarcely longer than that of the right, though

13

differing in the fact that the terminal joint is narrower and generally incurved;
inner ramus of same leg reaching beyond the middle of this joint. Body in both
sexes highly pellucid, with the oral area slightly tinged with red. Length of
adult female reaching to 9 mm., of male to 6'/. mm.

Remarks.—This species was established in the year 1838 by Kroyer, but was
very imperfectly characterised, for which reason it was not accepted by subsequent
authors as a distinct species, but only as a large variety of C. finmarchicus.
Dr. Giesbrecht has, however, recently vindicated its claim to be regarded as di-
stinct, having pointed out some distinctive characters of the female. The structure
of the hitherto unknown male also confirms the correctness of Dr. Giesbrecht’s
opinion about the distinctness of this form. It may be easily recognized from
the 2 preceding species, not only by its large size (it is indeed one of the largest
Calanoids known), but also by the angularly produced lateral corners of the last
pedigerous segment, and the comparatively short urosome. ‘The male, too, is fairly
well marked by the less prominent frontal part, but especially by the structure
of the last pair of legs.

Occurrence.—This form is occasionally found off the Finmark coast and
the Lofoten Islands, together with Calanus finmarchicus; but farther south it seems
to be wholly restricted to the great depths of the fjords, occurring under such
circumstances as far south as in the Christiania Fjord. It must evidently be
regarded here as a relict form, representing a remnant of the glacial fauna which
prevailed around our coasts in ancient times (the glacial period).

Distribution.—About the arctic character of this species no doubt can
arise, it being met with throughout the Polar Sea from Greenland to the Behring
Strait, and often in great abundance at the very surface of the water. In the
Polar basin explored by Nansen it was very common, occurring in the greater

number of the plankton-proofs examined.

Fam. 2. Eucalanide.

Characters.—Body, as a rule, very slender, with the cephalosome and
the Ist pedigerous segment generally coalesced, frontal part more or less pro-
duced, with 2 soft tentacular filaments below. Last pedigerous segment imperfectly
developed. Urosome comparatively short, consisting in female, as a rule, of only
3 segments, caudal rami partly confluent with the anal segment and somewhat

14

asymmetrical, caudal sete present in the normal number. Anterior antenne long
and slender, with the articulations somewhat reduced in number, and having some
of the setee much elongated, those attached behind to the penultimate and ante-
penultimate articulations, as in Calanus, densely plumose. Posterior antennee with
the inner ramus longer than the outer. Oral parts on the whole normal. Legs
comparatively short, especially the Ist pair, the rami of which have the number
of joints more or less reduced; terminal joint of outer ramus in 2nd to 4th
pairs with 3 spines outside. Last pair of legs, when present, very small, simple,
not natatory.

Remarks.—The forms belonging to this family are easily recognizable by
their slender, pellucid body—the cephalic part of which is generally much pro-
duced—-, by the very long and slender anterior antenne, and the comparatively
short urosome. They differ, moreover, very essentially from the Calanid@ in the
structure of the legs, especially the last pair, which are much reduced, and not
natatory in either of the sexes. According to Dr. Giesbrecht, this family com-
prises as yet 3 genera, viz., Hucalanus Dana, Rhincalanus Dana, and Mecynocera
Thompson. All the species belonging to these genera are southern in distribution,
none of them having hitherto been recorded from northern latitudes. I am, how-
ever, now enabled to state the occurrence of at least one species so far north as
to admit of being referred to the fauna of Norway.

Gen. 2. Rhinealanus, Dana, 1852.

Generic Characters.—Cephalosome produced in front to a nose-like pro-
jection carrying the rostral filaments below. Last pedigerous segment very small,
with the epimeral parts imperfectly developed. Urosome in female 3-articulate,
anal segment confluent with the caudal rami, which are only slightly asymmetrical,
and carry 2 of the sete outside, middle apical seta on left ramus greatly elon-
gated. Anterior antennz much longer than the body, and consisting (in female)
of 23 articulations only, the first 2 and the 7th and Sth being fused together.
Posterior antennze with the inner ramus moderately produced, outer ramus 8-arti-
culate, with the terminal joint very small. Posterior maxillipeds with the terminal
part shorter than either of the basal joints. First pair of legs with both rami
biarticulate, outer ramus af the 3 succeeding pairs with the spines of the outer
edge not defined from the joints. Last pair of legs (in female) 3-articulate.

Remarks.—This genus is chiefly characterised by the nose-like anterior

projection of the head, a character which has, indeed, given rise to the generic

name proposed by Dana. From the type genus, Hucalanus Dana, it is moreover
clearly distinguished by the presence of a 5th pair of legs, which in the
female of Lucalanus are wholly absent. Three species of this genus are as yet
known, one of them being now for the first time stated to occur also in the

northern oceans.

4. Rhinealanus nasutus, Giesbrecht.
(Pl. VI & VID).
Rhincalanus nasutus, Giesbrecht, Pelagische Copepoden (Fauna und Flora des Golfes von Neapel
XIX), p. 154, Pl. 3, fig. 6; Pl. 9, figs. 6, 14; Pl. 12, figs. 9—12, 14, 16, 17; Pl. 35, figs. 46, 47, 49.

Specific Characters.—KFemale. Body exceedingly slender and elongated,
with the anterior division, seen dorsally, narrow oblong in form, greatest width
not even attaming '/, of the length, and occurring behind the middle, cephalic
part gradually attenuated, though slightly widening at the insertions of the anterior
antenne, and produced beyond the latter to a conical anteriorly-pointing projec-
tion; rostral filaments not visible in the dorsal view of the animal. Anterior
body-segment (the combined cephalosome and Ist pedigerous segment) nearly
twice as long as the remaining part of metasome. 2nd, 3rd and 4th pedigerous
segments each with 2 small subdorsal, and 2 lateral denticles on the hind edge.
Urosome about equalling in length '/; of the anterior division, genital segment
with 2 small dorsal denticles in the middle. Caudal rami somewhat instricted
in their outer part, left ramus a little longer than right, innermost seta of both
rami much shorter than the others. Anterior antenne exceedingly elongated,
when reflexed, reaching beyond the caudal rami by about 1/; of their length, and
inserted at rather a long distance from the posterior antenne and the oral parts,
which are closely crowded together. Last pair of legs very small, each of the
2 outer joints with a ciliated seta inside, terminal joint moreover carrying at the
tip a similar seta and, outside it, a slender unciliated spine. Body highly pel-
lucid, and almost without any pigment. Length of adult female 5.40 mm.

Remarks.—This species was first described by Dr. Giesbrecht from the
western part of the Mediterranean. It is easily recognized by the shape of the
frontal projection, and the exceedingly long and slender anterior antenne. It is
moreover distinguished from the type species, R. cornutus Dana, by a somewhat
different structure of the last pair of legs.

Occurrence.—Two well-preserved female specimens of this peculiar Cala-
noid were found in a sample of plankton taken during the cruise of the “Michael
Sars” at Stat. 10, located at some distance east of Iceland, the depth being stated

to be between 250 and 400 meters. Another female specimen was found at an

16

earlier date in a sample taken by Dr. Hjort in the North Sea, about midway
between Scotland and Norway. Though not yet found in the immediate vicinity
of the Norwegian coast, this form certainly has a claim to be included in the
fauna of Norway.

Distribution — Western part of the Mediterranean, off Gibraltar, the Pacific
from the Magellan strait northwards to Lat. 6° N. (Giesbrecht); Atlantic Ocean
from Lat. 6° N. til 48° N (Cleve); ? N. of Scotland (Moebius).

Fam. 3. Paracalanide.

Characters.—Body less slender, with the cephalosome not produced in
front, and, as arule, coalesced with the 1st segment of metasome, rostral filaments
as in Calanus. The last 2 segments of metasome fused together. Urosome short,
in female generally 4-articulate; caudal rami well defined, with only 4 of the
apical sete distinctly developed. Anterior antenne in female 25-articulate, sub-
apical setz not plumose, those in male greatly thickened at the base, with the
proximal articulations much reduced in number, and clothed with comparatively
short, club-shaped sensory appendages. Posterior antennz with the outer ramus
scarcely longer than the inner, and having the terminal joint comparatively short.
Oral parts in female normal, in male much reduced. Legs rather slender, inner
ramus in Ist pair biarticulate, in the 3 succeeding pairs 3-articulate, and partly
spinulose on the hind face, outer ramus in the latter with the terminal joint
narrow and armed with only 2 spines outside. Last pair of legs, when present,
poorly developed, not natatory, left leg in male longer than right, which is some-
times wholly wanting.

Remarks.—In the structure of the several appendages, the forms belonging
to this family agree on the whole with those of the Calanide, differing, however,
rather materially in the circumstance of the 5th pair of legs not being natatory
in either of the sexes, but very small and simple, or wholly wanting in the female.
The adult male has the anterior antenne transformed in a similar manner to
that in the Calanide, but is distinguished by the great reduction of the oral parts,
especially the maxillipeds. The family comprises as yet 3 genera, viz., Para-
calanus Boeck, Acrocalanus Giesbrecht, and Calocalanus Giesbrecht. Only the

first of these genera is represented in the northern oceans.

oe

Gen. 3. Paracalanus, Boeck, 1864.

Generic Characters.—Body comparatively short and stout. Cephalosome
wholly coalesced with the Ist pedigerous segment, and slightly carinated dorsally
in the male; frontal part rounded. Lateral corners af last pedigerous segment
not produced. Urosome in female distinctly 4-articulate, with the genital segment
comparatively short. Caudal rami short, obtusely truncated at the tip, apical sete
but slightly divergent. Anterior antenne scarcely longer than the body, their
proximal part exhibiting in male 2 large segments clothed below with short sensory
appendages. Ist pair of legs with a well-marked deflexed seta at the end of the
basal part inside. Terminal joint of outer ramus in the 3 succeeding pairs finely
denticulate along the outer edge. Last pair of legs in female very small, bi-
articulate; left leg in male 5-articulate, right leg as in the female.

Remarks.—This genus was established in the year 1864 by Boeck, to
comprise a small Calanoid formerly described by Claus as Calanus parvus. It
may, however, be remarked, that the genus Calanus, as defined by Claus, does
not answer to Leach’s genus, and in reality comprises several genera not even
belonging to the family Calanide in the restriction here adopted. Besides the
type species described below, another nearly-allied species has been recorded by
Dr. Giesbrecht as P. aculeatus, and the imperfectly characterised Calanus pygmeus

of Claus probably also belongs to the same genus.

5. Paracalanus parvus, (Claus).
(Peay Ses DX):
Calanus parvus, Claus, Die frei lebenden Copepoden, p. 173, Pl. XXVI, figs. 10—14, Pl. XXVII,
figs. 1—4.

Specific Characters.—Female. Anterior division of body, seen dorsally,
oblong oval, somewhat more tapering behind than in front, greatest width about
equalling 1/; of the length. Anterior body-segment (combined cephalosome and
lst pedigerous segment) about twice the length of the remaining part of metasome,
front evenly rounded. Lateral corners of last pedigerous segment rounded off.
Urosome about equalling */; of the length of the anterior division, genital and anal
segments of about equal length and much larger than either of the 2 middle seg-
ments. Caudal rami scarcely exceeding the anal segments in length, sublinear in
form, apical sete of moderate length, the innermost but one the longest. Anterior
antennz, when reflexed, scarcely reaching beyond the pennultimate caudal segment,
some of the articulations less distinctly defined. Posterior antennz with the outer

3 — Crustacea.

18

ramus a little shorter than the inner, and 7-articulate. 2nd joint of inner ramus
in the 2nd and 3rd pairs of legs with an obliquely transverse row of spinules on
the hind face. Last pair of legs with the distal joint narrow linear, carrying on
the tip a slender spine, outside which a much smaller spinule is secured.

Male dittering considerably in its external appearance from the female.
Cephalosome somewhat incrassated and exhibiting along the dorsal face an obtuse
keel, front considerably more prominent than in female. Urosome rather slender,
5-articulate, with the 2nd segment the largest; caudal rami, as in the male of
Calanus, mobile. Anterior antenne rather strongly built, the 2 basal segments
defined by a conspicuous constriction, the distal one the longer and consisting of
5 united articulations. Posterior antenne with the outer ramus consisting of
only 6 joints, the last very small, and having only a single seta. Anterior maxil-
lipeds quite rudimentary, knob-like. Posterior maxillipeds likewise much reduced,
terminal part indistinctly articulated and carrying behind 3 strong plumose sete,
in front only slight rudiments of bristles. Left leg of last pair with the terminal
joint a little shorter than either of the 2 preceding joints, somewhat lamellar, and
carrying on the tip 2 small unequal spinules.

Colour. Body of femal pellucid with a bluish tinge, and often exhibiting
a broad transverse band of a dark red hue across the middle of the anterior
division. Body of male generally of a more uniform yellowish hue.

Length of adult female scarcely exceeding 1 mm., of male about the same.

Remarks.—Dr. Giesbrecht is inclined to believe that the form observed
by Boeck might be different from Claus’s species. This is certainly not the case,
as may be proved by comparing the figures here given with those of Claus and
Giesbrecht. It is one of the smallest known Calanoids, and thus fairly deserves
its specific name.

Occurrence.—I have found this form rather plentiful in the Christiania
Fjord, as also off the southern coast of Norway. It does not seem to occur
farther north, however; for Mr. Nordgaard, who has subjected the marine Copepoda
of the neighbourhood of Bergen to a careful examination, has not seen any speci-
men of this form, nor have I myself ever found it in the numerous samples of
plankton from the northern ocean that I have examined. It is generally met with
at the very surface of the water, both in the open sea and close to the shores,
not infrequently even in pools left by the tide.

Distribution.—The range of this Calanoid is pronouncedly southern and
quite extraordinarily wide, it having been recorded from the western part of the
Baltic, the North Sea, the British Channel, the western coast of France, the
Mediterranean, the Atlantic Ocean and the Pacific from Lat. 61° N. to 52° S.

Fam. 4. Pseudocalanide.

Syn: Clausocalanine, Giesbrecht (part).

Characters.—Cephalosome, at any rate in female, coalesced with the Ist
segment of metasome, front unarmed, or provided below with 2 soft tentacular fila-
ments, as in Calanus. Last segment of metasome united with the preceding one,
lateral corners not produced. Urosome in female 4-articulate, in male 5-articulate
and having the anal segment shortened. Caudal rami well defined, with only 4
of the marginal sete developed. Anterior antenne in female 24-articulate, 8th
and 9th articulations being coalesced, in male thickened at the base and clothed
with slender, sabre-like sensory appendages, number of articulations reduced.
Posterior antenne with the outer ramus always longer than the inner. Oral
parts in female normal, in male much reduced. Legs slender, inner ramus of 1st
pair uniarticulate, of 2nd pair biarticulate, of 3rd and 4th pairs 3-articulate;
terminal joint of outer ramus in 2nd to 4th pairs narrow, with 3 spines outside,
apical spine coarsely serrate. Last pair of legs in female small, simple and 3-arti-
culate, or wholly wanting; those in male likewise simple, but rather slender, left
leg 5-articulate, right more or less styliform.

Remarks.—This family answers to the subfamily Clawsocalanine of Dr.
Giesbrecht. As, however, the genus Pseudocalanus is of much earlier date than
Clausocalanus, the family ought to be named as above. From the Paracalanide
this family chiefly differs in the structure of the legs, partly also in that of the
posterior antenne. Dr. Giesbrecht refers to this family the following 6 genera:
Clausocalanus Giesbr., Ctenocalanus Giesbr., Pseudocalanus Boeck, Drepanopus
Brady, Spinocalanus Giesbr. and Moebianus Giesbr. The last-named genus
(= Stephos Scott) ought, however, in my opinion to be discarded and transferred
to a separate family in the section’ Jsokerandria, to be treated of farther on.

Of the remaining 5 genera, 2 are represented in the fauna of Norway.

Gen. 4. Pseudoealanus, Boeck, 1872.

Syn: Clausia, Boeck (not Claparéde).
Lucullus, Giesbrecht.

Generic Characters. —Body of comparatively slender form, with the cephalo-
some and lst segment of metasome coalesced in both sexes, front rounded and

carrying 2 soft tentacular filaments below. Urosome in both sexes very slender,

20

with the caudal rami sublinear in form. Anterior antenne shorter than the body,
in the male with the 2 proximal articulations coalesced to a large flattened seg-
ment, the succeeding 5 articulations well defined. Posterior antenne with the
outer ramus 7-articulate, terminal joint rather large. Inner ramus of 2nd to 4th
pairs of legs without any spinules on the hind face. Last pair of legs wholly
wanting in female, those in male yery slender, right leg styliform and shorter
than the left.

Remarks.—This genus, established by Boeck, was first named Clausia in
honour of the late Prof. C. Claus. As however this name had been previously
appropriated by Claparéde to designate a genus of parasitic Cyclopoida, it was
subsequently by the same author changed to Pseudocalanus. Dr. Giesbrecht, on
describing the Copepoda from the bay of Kiel, did not at first recognize Boeck’s
genus, to which the name Lucullus was applied; but in a postscript to his treatise
he has admitted the identity of these 2 genera. Besides the well-known form
described below, 2 other species have been added by the present author from
Nansen’s Polar Expedition, viz., P. major and P. pygmeus. The latter, however,
I am now inclined to regard as belonging to a new nearly-allied genus, for which

the name Microcalanius may be proposed.

6. Pseudocalanus elongatus, Boeck.
(Pl, Xe):
Clausia elongata, Boeck, Oversigt over de ved Norges Kyster iagttagne Copepoder.

Chr. Vid. Selsk. Forh. 1864, p. 234.

Syn: Lucullus acuspes, Giesbrecht.
» Calanus Clausii, Brady.

Specific Characters.— Female.

Anterior division of body, seen dorsally,
oblong oval in shape, greatest width but slightly exceeding 1/; of the length,
frontal part but little prominent, and, seen latcrally, narrowly rounded; lateral
corners of last segment of metasome obtusely rounded. Urosome somewhat
exceeding half the length of the anterior division, genital segment considerably
larger than any of the others and slightly dilated in front. Caudal rami exceed-
ing in length the anal segment, and transversely truncated at the tip, exhibiting
a small dentiform projection outside the apical sete. Ovisac present, of irregular
rounded form, but easily detached, and containing a very limited number of ova.
Anterior antennz, when reflexed, scarcely reaching beyond the 2nd caudal segment,
the 2 basal articulations imperfectly separated. Posterior antennze with the outer
ramus about 1/; longer than the inner. Ist pair of legs much smaller than the

others, terminal joint with only a single setiform spine outside.

21

Male rather unlike the female, and of considerably smaller size. Cephalo-
some slightly dilated in front, but scarcely carinated dorsally. Urosome very
narrow, with the anal segment shorter than in female, and somewhat dilated
distally; caudal rami very mobile, finely ciliated inside, and having the terminal
edge somewhat produced in the middle. Anterior antenne with the number of
articulations considerably reduced, a fusion having taken place, not only of the 2
proximal ones, but also of the 8th to 12th and of the 20th and 21st articulations.
Last pair of legs rather asymmetrical, left leg much the longer, with the 2nd and
3rd joints slightly dilated distally, terminal joint very small and tipped with a
slender spinule; right leg not nearly reaching to the end of the penultimate joint
of left, and terminating in a straight, subulate point.

Colouwr.—Body in both sexes very pellucid, though generally with a faint
reddish yellow tinge; oral area, as a rule, tinged with crimson, and the genital
protuberance of the female with light green.

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

Remarks.—This form was first recorded by Boeck from the Norwegian
coast under the name of Clawsia elongata, and was subsequently rediscovered in
the bay of Kiel, by Dr. Giesbrect, who described it as Lucullus acuspes. It is
easily recognized from the other Norwegian Amphascandria by its slender and
elongated tail, a character which has, indeed, given rise to the specific name pro-
posed by Boeck.

Occurrence.—I have met with this form very frequently along the whole
Norwegian coast from the Christiania Fjord to Vadso, both in the open sea and
close to the shores, where it is occasionally left in tidal pools. It often occurs
at the very surface of the water; but it sometimes also seems to descend to
greater depths, though on the whole it may be regarded as a true pelagic form.
Specimens are not infrequently found carrying a small number of ova enclosed in
a thin-skinned, rounded ovisac, which, as usual, is appended to the ventral side
of the genital segment; but this ovisac is so very fragile, that at the slightest
touch it may become detached. Male specimens are much more scarce than
females and, when alive, may be easily recognizable even to the naked eye by
their somewhat different jerky movements.

Distribution.— Unlike Paracalanus parvus, this Calanoid has a pronoun-
cedly northern range, the most southern place where it has been observed being
the northern coast of France (Canu). On the other hand, it is distributed
throughout the whole northern Ocean from Baffin’s Bay in the west to the New
Siberian Isles in the east. It also inhabits the Baltic together with other forms

of evidently arctic origin.

Gen. 5. Spinocalanus, Giesbrecht, 1892.

Generic Characters.—Body comparatively short, with the urosome not
nearly so elongated as in Pseudocalanus. Front quite unarmed, without any
tentacular filaments below. Anterior antennze longer than the body, and very
flexible; those in male transformed in a manner similar to that in Pseudocalanus.
Posterior antennse with both rami rather produced, the outer one being the longer.
Posterior maxillipeds unusually slender, with the terminal part much elongated
and armed distally with coarsely ciliated procurved sete. Legs very slender,
inner ramus of 2nd to 4th pairs densely spinulose on the hind face. Last pair
of legs wanting in female, in male of comparatively small size, right leg not
styliform.

Rtemarks.—This genus was established in the year 1892 by Dr. Giesbrecht,
to include a small Calanoid procured from very great depths in the tropical part
of the Pacific. The genus differs from Pseudocalanus chiefly in the total absence
of the usual tentacular filaments at the front, the less slender urosome, the very
long anterior antenne, the peculiar shape of the posterior maxillipeds, and finally
in the spiny armature of the inner ramus of the 2nd to 4th pairs of legs. In
the northern ocean this genus is represented by a species closely allied to the
typical one, and first described by the present author from Nansen’s Polar Ex-

pedition. This species has proved also to belong to the fauna of Norway.

7. Spinoecalanus longicornis, G. O. Sars.
(Pl. XII).
Spinocalanus longicornis, G. O. Sars, The Norwegian North Polar Expedition. V. Crustacea, p. 75,
1G DO:G0

Specific Characters.—Female. Anterior division of body, seen dorsally,
oblong oval, greatest width somewhat exceeding 1/; of the length, front obtusely
rounded; seen laterally, evenly vaulted above, with the front narrowly produced
and without any trace of a rostrum or tentacular filaments below. Lateral corners
of last segment of metasome obtusely rounded off. Urosome scarcely exceeding
in length 1*/, of the anterior division, genital segment comparatively short and
greatly protuberant below; caudal rami very short, being scarcely longer than
they are broad, apical sete about as in Pseudocalanus. Anterior antenne exceed-
ing the body by about 1/; of their length, penultimate joint provided in front
with an unusually long and slender bristle. Posterior maxillipeds with the 2nd

joint of the terminal part fully as long as the 3 succeeding joints combined.

23

Outer ramus of 2nd to 4th pairs of legs provided with scarcely any spinules on
the hind face, apical spine exceedingly slender, exceeding the length of the ter-
minal joint. Length of adult female 1.60 mm.

Remarks.—As stated above, this species was first described by the present
author from Nansen’s Polar Expedition. It is closely allied to the type species,
S. abyssalis Giesbrecht, but is apparently distinct, the spiny armature of the legs
and maxillipeds being, to judge from the figures given by Dr. Giesbrecht, much
coarser in the latter species.

Occurrence.—I have not myself ever observed this form off the coast of
Norway; but Mr. O. Nordgaard has recently found it in the Osterfjord near
Bergen at the considerable depth of from 400 to 600 meters, together with other
relict arctic forms. The figures here given are from a well-preserved female
specimen kindly sent to me by that naturalist.

Distribution.—The Polar Sea in about the 80th degree of latitude, at 2
different Stations.

Fam. 5. Atideide.

Characters.—Body, as a rule, not very slender, the anterior division being
more or less tumefied. Cephalosome coalesced with the lst segment of metasome,
front generally projecting below into a highly chitinised bifid or simple mucronate
rostrum, more rarely quite unarmed. Last segment of metasome united with the
preceding one, and generally having the lateral corners produced behind. Urosome
in female 4-articulate, in male, as usual, 5-articulate and very narrow, with the
anal segment much shortened. Caudal rami generally short, with only 4 of the
marginal set distinctly developed, in male mobile as in the preceding families.
Kye generally well developed, though in some cases wholly absent. Anterior
antenne in female of moderate length, or comparatively short, with the 8th and
9th articulations confluent; those in male transformed in a manner similar to
those in the Pseudocalanide, though having the sensory appendages more densely
crowded together on the proximal part, and very long and band-like. Posterior
antenne witb the outer ramus generally longer than the inner. Oral parts in female
on the whole normal; posterior maxillipeds, however, with the terminal part reflexed.
Oral parts in male considerably reduced. Legs of a structure similar to that in
the Pseudocalanide, though considerably more strongly built. Last pair of legs

always wanting in female, in male generally rather simple in structure.

24

Remarks.—This family, answering to the subfamily @tidiina of Giesbrecht,
forms, as it were a transition between the Pseudocalanide and Euchetide. One of
the forms, indeed, now comprised within the present family was referred by Boeck
to the genus Pseudocalanus and another form to the genus Eucheta. I think,
however, that Dr. Giesbrecht is right in keeping these forms apart from both the
above-named families. This family comprises as yet no less than 9 different genera,

4 of which are represented in the fauna of Norway.

Gen. 6. AXtideus'), Brady, 1883.

Syn: Psewdocalanus Boeck (part).

Generic Characters—Cephalosome in female highly vaulted anteriorly,
almost carinated dorsally, and projecting below into a strong bifurcate rostrum,
in male far less vaulted, and without any trace of a rostrum. Last segment of
metasome produced behind on each side to a strong mucroniform process more
developed in female than in male. Urosome in female comparatively short, ge-
nital segment very protuberant below, caudal rami less shortened than in the
other forms, with the appendicular bristle of the inner corner unusually long and
slender, outermost (5th) apical seta only present as a rudiment. Urosome of male
very slender, with the anal segment considerably shortened, almost inconspicuous.
Kye subventral, of a somewhat irregular form and obliquely disposed, with a
distinct lenticular body below. Anterior antenne in female comparatively slender,
with some of the bristles of the anterior edge rather elongated, last joint very
small and imperfectly defined from the penultimate one; those in male shorter,
with the 7 proximal articulations well defined, whereas a fusion has taken place
of some of the others. Posterior antenne with the outer ramus but little longer
than the inner, and 7-articulate. Posterior maxillipeds not much elongated, 2nd
basal joint fusiform, terminal part comparatively short, reflexed. Inner ramus of
2nd pair of legs imperfectly biarticulate. Left leg of last pair in male very
slender, 5-articulate, right leg wholly wanting.

Remarks.—This genus was established in the year 1883 by Brady, to
include a Calanoid procured during the Challenger Expedition in the Indian

Ocean, and regarded as new to science. The genus, though insufficiently charac-

1) This name is spelt by Brady tidius; but, as recently observed by Dr. Giesbrecht,
this is unquestionably incorrect, as it is derived from the Greek word dettdevs, an eaglet.

terised, was accepted by Dr. Giesbrecht, who describes a form from the Mediter-
ranean, which he regards as identical with Brady’s species, though in some
respects it seems to differ rather conspicuously. Neither of these authors was
aware that a very similar form was recorded many years ago from the Norwegian
coast by Boeck, who applied to it the very same specific name as that proposed
by Brady. The validity of these 3 forms as distinct species is perhaps still somewhat
questionable, the similarity of the Norwegian form with that described by Brady
being in particular so very close, that I should have been much inclined to
regard the two as identical, if the widely remote occurrence of these 2 forms
did not seem to forbid such an identification. The genus is easily recognized,
at. any rate in the female sex, by the very strong and highly chitinized bifurcate
rostrum, the boldly vaulted cephalosome, and the coarse mucroniform projections

of the last segment of the metasome.

8. Atideus armatus, Boeck.
(Pl. XIII & XIV.)
Fseudocalanus armatus, Boeck. Nye Slegter og Arter af Saltvands Copepoder. Christiania
Vid. Selsk. Forhandl. 1872, pag. 6.

Specific Characters—Female. Anterior division of body, seen dorsally,
oval fusiform, greatest width considerably exceeding '/; of the length and occurring
in the middle, anterior extremity more narrowed than the posterior, and pro-
jecting somewhat between the insertions of the anterior antenne; seen laterally,
strongly vaulted in front, with the dorsal margin of cephalosome forming a bold
and continuous curve gup to the tip of the rostrum, the latter scarcely incrassated
at the base, rami sharply pointed and separated by an even emargination. Lateral
corners of last segment of metasome gradually exserted to strong mucroniform
processes pointing straight behind, and reaching about to the end of the genital
segment. Urosome scarcely exceeding in length 14/; of the anterior division,
genital segment comparatively short and rather dilated in the middle. Caudal
rami considerably longer than the anal segment, sublinear, finely ciliated inside,
innermost but one of the apical sete much longer than the others. Anterior
antennz, when reflexed, reaching to about the base of the caudal rami.

Male considerably smaller than female, and of much more slender form
of body, front narrowly rounded and quite unarmed; posterior projections of last
pedigerous segment far less developed than in female. Urosome exceedingly nar-
row, and exceeding in length '/; of the anterior division; caudal rami generally
spread to each side. Anterior antenne, when reflexed, scarcely reaching to the

4 — Crustacea.

26

end of the 2nd caudal segment. Left leg of last pair nearly as long as the
urosome, 3rd joint the longest, terminal one rather small and finely ciliated.

Colour.—Body in both sexes very pellucid, in female being banded
transversally with light red. Length of adult female 1.80 mm., of male 1.45 mm.

Remarks.—No doubt can arise as to this being the true Pseudocalanus
armatus of Boeck. If the form recorded by Brady should prove to be a different
species, it must consequently have another specific name. In any case these 2
forms are very closely related, whereas the Mediterranean form described by Dr.
Giesbrecht seems to differ from the Norwegian form in several respects. At the
base of the rostrum, for instance, there is a conspicuous thickening not found in
the latter form, and the posterior projections of the last segment of the metasome
are much coorcer, reaching, according to the figures given, beyond the 2nd caudal
segment. The colouring of the animal is also rather different, to judge from the
coloured figure given on Pl. 2.

Occurrence.—Boeck found this form at Haugesund, west coast of Norway,
at a depth of 30 fathoms. I have myself observed it, though in rather small
numbers, at about the same depth in 2 different localities, viz., in the upper part
of the Christiania Fjord (Bundefjord), and in the Brevik Fjord near Langesund.
Moreover some few specimens were found in a sample of plankton taken during
the cruise of the “Michael Sars” in the Storfjord (Nordmgre), and in another
sample from Stat. 11 (north of Iceland). A solitary specimen was finally found
in a sample taken off the Finmark coast NW. of Nordkyn. Mr. Nordgaard has
observed this form in the neighbourhood of Bergen.

Distribution.—If the form recorded by Brady should in reality prove to
be identical with Boeck’s species, the distribution of this Calanoid would be quite
perplexing; but I still regard the identification of these 2 forms as somewhat
questionable, and I should indeed be more inclined to believe that the present
form is exclusively a North Atlantic species. It is, however, certainly not of
arctic origin, since it did not occur in any of the numerous samples of plankton
taken during Nansen’s Polar Expedition, and has never been found anywhere in
the Arctic Ocean.

Gen. 7. Chiridius, Giesbrecht, 1892.
Syn: Hucheta, Boeck (part.)

Generic Characters.—Cephalosome but slightly vaulted in front, rostral
projection very small, bifid, or wholly absent. Last segment of metasome pro-
duced behind on each side to a more or less developed spiniform process. Uro-
some about as in ditideus but with the genital segment in female less protuberant
below. Caudal rami very short, with the appendicular bristle not prolonged, and
proceeding from the lower face of the rami. Eye comparatively large, and placed
less ventrally than in dvtideus. Anterior antennz much shorter than the body,
but rather slender, and resembling in structure those in the above-named genus.
Posterior antenne with the outer ramus much longer than the inner. Mandibles in
female with the masticatory part very largely developed, inner ramus of the palp,
however, unusually small. Masticatory parts of mandibles and maxille in male
quite rudimentary. Anterior maxillipeds in female normal, in male much reduced.
Posterior maxillipeds with the 2nd basal joint long and slender, terminal part
comparatively short and reflexed. Natatory legs of a structure similar to that in
Attideus. Both legs of last pair in male well developed, 5-articulate, the right
one being the stronger, 2nd joint in each leg sometimes with a small appendage
inside (rudiment of an inner ramus).

. Remarks.—This genus was established by Dr. Giesbrecht in the year
1892, to include a Mediterranean species, C. Poppei, which, however, is rather
imperfectly figured. In the year 1900, I was able to state that this genus is well
represented also in the northern ocean, 3 different species having been described
from Nansen’s Polar Expedition, one of them being at that time considered to be
identical with Boeck’s Kucheta armata. The genus is closely allied to dttideus,
from which it differs, however, in the far less developed rostrum, the different
shape of the cephalosome, and partly also in the structure of the posterior an-
tenn, mandibles and posterior maxillipeds. Finally, both legs of the last pair
in the male are well developed. 3 species, to be described below, belong to the

Norwegian fauna.

9 Chiridius armatus, (Boeck).
(Pl. XV & XVI.)

Eucheta armata, Boeck, Nye Slegter og Arter af Saltvands-Copepoder. Christ. Vid. Selsk.
Forhandl. p. 39.

Specific Characters.—Female.—Anterior division of body somewhat tumid,
seen dorsally, oblong oval in form, anterior extremity slightly contracted, but

scarcely projecting at all between the insertions of the anterior antenne, posterior
subtruncate, with the lateral corners drawn out to comparatively short and some-
what divergent acute projections; seen laterally only slightly vaulted anteriorly,
front narrowly rounded and armed below with a very small bifid rostrum. Uro-
some considerably exceeding 1/; of the length of the anterior division, genital
segment but slightly dilated. Caudal rami scarcely longer than the anal segment
and somewhat divergent, apical sete of moderate length and densely plumous.
Eye unusually large and distinctly bilobate, dark red in colour. Anterior antennee,
when reflexed, reaching to about the middle of the 2nd caudal segment. Posterior
antennee with the outer ramus about !/; longer than the inner. Ist pair of legs
with a well-marked setiform spine outside the Ist joint of the outer ramus; 2nd
pair with the inner ramus distinctly biarticulate.

Male nearly as large as female, but of more slender form; rostral pro-
jection and lateral processes of last segment of metasome about as in female.
Urosome, as usual, 5-articulate, with the anal segment shortened, and the caudal
rami mobile. Anterior antenne considerably shorter than in female, not nearly
so long as the anterior divisions, and somewhat incrassated at the base, con-
sisting of 23 articulations, the proximal ones with long band-like sensory appen-
dages. Mandibular palps much more strongly built than in female, with the inner
ramus well developed and carrying at the tip very coarse diverging sete. Last
pair of legs well developed, the right leg being considerably stronger than the
left, both with a small unicarticulate appendage inside the 2nd joint, representing
a rudiment of the inner ramus, 3rd joint of right leg somewhat curved, and much
larger than the others, 4th joint slightly dilated distally, 5th transformed to a
slender claw, obtuse at the tip.

Colour.—Body in both sexes pellucid with a faint rosy tinge, intestine
in female translucent with a bright red colour, ovarial tubes opaque whitish.

Length of adult female 4 mm., of male about the same.

Remarks.—This form was recorded in the year 1872 by Boeck as Huw-
cheta armata; but the characterisation of the species was very insufficient, for
which cause it has not been recognized by subsequent authors, even as regards
its generic relation. By comparing the drawings left by that author, however,
I have convinced myself that the form here under consideration is the true
Hucheta armata of Boeck. On the other hand, the form from Nansen’s Polar
Expedition, previously described by the present author under this name, has
turned out to be a different, though closely allied, species, as subsequently shown.
. Occurrence. —Boeck found this form at Skudesnes, west coast of Norway,
at a depth of 300 fathoms. JI have myself met with this Calanoid in great

epoda

I

Calanorda

Co

Calanida.

whee

im

Tryktiden private Opmaaling, Chra.

Calanus finmarchicus, (Gunner)

G.0. Sars autogr.

Copepoda

Calanide. Calanoida PL. Il.

G.0. Sars autogr. Trykt den private Gpreaaling Cheat
Calanus finmarchicus, (Gunner.
continued

Ela

pepoda
Calanorda

Co

Calanide.

ass! aa oe
3 st

a. ne A pa (= f L =
= = Sele lL fe bea =

ee SO

—

NES

2 = ee ( if \) %
kui N\A

/

Saye pao ok

oe private Opmaaling, Chra

Calanus finmarchicus, (Gunner.

G.0. Sars auto gr.

(male)

Co

pepoda
Calanorda

ge nlile

Petan de.

/

/
/
4
je=

————
‘

=

==

YS beet)
—— —— -

+—

LVI) ile Z Ui.

y,

Trykt iden private Opmaaling, Chra.

Calanus helgolandicus (Claus.)

6.0. Sars autogr.

~~
o

pepoda
fanorda

Ca

exe

Calanide.

nase

ifs

SAA ef

| Hs

LEE

Tryktiden private Opmaaling, Chra.

6.0. Sars autogr.

Calanus hyperboreus, Kroyer.

PEEVE.

pepoda
Calanorda

Oxo

Eucalanideas.

P jar. ities
7 a rome. is
Propeehes w 4 IE aes

Tryktiden private Opmaaling, Chra

—_ rey
: Coe — ae Ss Sea

=

nasutus, Giesbr.

Rhincalanus

——

=

6.0. Sars autogr.

——

Copepoda
Calanorda

Eucalanidas.

Tryktiden private Opmaaling, Chra.

Rhincalanus

6.0. Sars autogr.

nasutus, Giesbr.

continued

pepoda
Calanortda

Co

Paracalanida.

Tryktiden private Opmaaling,Chra.

Paracalanus parvus (Claus|

G.0. Sars autogr.

ne

7

ot ge

oa
[aes
4: wy

=
O
*
4
i
.
— i]
=! =)
- io -y
= 4
Jae - i
m0 af! » vd a ‘

,
7 7
7
i
ke
‘
4 o
ane

A

=

2) «ees

Copepoda

Paracalanide. Calan o rera:. | Ee

G.0.Sars auto gr. _ Tryktiden private Opmaaling, Chra.
Paracalanus parvus (Claus)

continued

BIGK:

pepoda
Calanorda.

Ore

Pseudocalanide.

Ce ee

ae

Tryktiden private Opmaaling, Chra.

elongatus, Boeck.

6.0. Sars autogr.

Pseudocalanus

Plex

pepoda
Calanorda.

ore

Pseudocalanidee.

Tryktiden private Opmaaling, Chra

elongatus, Boeck.

continued

6.0. Sars autogr.

Pseudocalanus

PL XI.

pepoda
Calanorda.

Co

Pseudocalanida.

Tryktiden private Opmaaling Chra

G.0.Sars.

G.0. Sars auto gr.

longicornis ,

Spinocalanus

Copepoda.

Etidiide. Ca lanorda- PI. XII.

6.0. Sars autogr. Trykt iden private Opmaaling, Chra.
Atidius armatus, (B oeck)

Copepoda

Etidiidas. Calanorda.

an
aN

G.0. Sars autogr. Trykt iden private Opmaaling, Chra
Atidius armatus, (Boeck) 7

continued

®
7 4
7 _ 7
Pu
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A :
5
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£
t. ~
7
i
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.
.
s
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a
; 2 =
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a re
7 Ss
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no
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& a 7
ie .
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=
-
; =
.
a
+s
‘on
So
oi
.
a

~

4 ae G
a. tee ome Sip; a
a =)

pepoda
fanoida

Ca

Cis

Atidiida.

Tae

J = o
Ai i
a ee i
ic ==
x .

Ne SALA: a ae =~ bs = s —_
5 NV if tise = = ; se N
: BA. Ne \ / y ae tee SS * = a vay \
Sx: . ’ VL se porn) | Fe Va
fe Yb ff ——— — } | WiiWii i] Ewe
Sy ry = = LE Nid tee —
= Re lisxg. fT _ - — ) eh <
, / ES aces TIT ‘ 7 RO, a> SNS a A
SF me : a g F
N

Tryktiden private Opmaaling, Chra.

Chiridius. armatus, (Boeck|

6.0. Sars autogr.

Rtidiidee.

G.0. Sars auto gr.

Copepoda

Calanoirda.

Chiridius. armatus, (Boeck.
continued

)

PL XVI.

Tryktiden private Opmaatling, Chra.

AN ACCOUNT

OF THE

CRUSTACEA

OF

NORWAY

: WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

: d BY

G. O. SARS

| VOL. IV

COPEPODA
CALANOIDA (

PART III & IV
ATIDEIDZ (concluded), EUCHETIDE, PHAENNIDE

WITH 16 AUTOGRAPHIC PLATES

wees Co 18 oe ud) OS ey cri id OM | ile <4 Ye n word Nene Fo el
POMS Sah ER ees ONE AMOR ME Peo nd Oe Manyey MUR Wak miamen | MS Nis Be Cet

>)

és
;

BERGEN
St PUBLISHED BY THE BERGEN MUSEUM
BS SOLD BY
= ALB. CAMMERMEYER’S FORLAG, CHRISTIANIA
: 1902

i Hs Nt
)

ie ee al

tee

29

abundance in almost all our deep fjords, from the Christiania Fjord up to the
Vestfjord, but only in greater depths than 100 fathoms. It is accordingly, at any
rate off the coast of Norway, a pronounced deep-water form, though it is very
probable that in more northern latitudes it may ascend nearer to the surface.
Distribution.—Though 1 am much inclined to believe that this form is
of arctic origin, the statements about its occurrence in the Arctic Ocean cannot be
regarded as fully reliable, as it may very easily be confounded with the succeeding
species. In the Polar basin investigated by Nansen, the present species did

not occur.

10. Chiridius obtusifrons, n. sp.
(Pl. XVII.)
Chiridius armatus, G. O. Sars. The Norw. North Polar Expedition. Crustacea, p. 64, Pl. XVII
(not Boeck.)

Specific Characters.—Female.—Very like the preceding species, though
perhaps a little more slender of form. Front without any trace of a rostrum.
Lateral corners of last segment of metasome, as in C. avmatus, drawn out to
comparatively short and slightly divergent acute projections. Urosome rather
slender, attaining almost half the length of the anterior division; caudal rami
somewhat more produced, exceeding in length the anal segment, and but slightly
diverging. Anterior antenn scarcely longer than the anterior division of the
body. Posterior antennze with the inner ramus rather short and stout, outer one
fully twice its length. First pair of legs about as in C. armatus. Inner ramus
of 2nd pair uniarticulate, of 3rd and 4th pairs imperfectly 3-articulate, the 2
basal joints being partly confluent. M/ale much smaller than the female, but
otherwise resembling that of OC. armatus. Last pair of legs, however, much more
slender, and without any trace of an inner appendage to the 2nd joint. Length
of adult female 4.20 mm., of male 2.90 mm.

Remarks.—As stated above, this form was at first regarded by the present
author as identical with Boeck’s species, to which it certainly bears a perplexing
resemblance. On a closer comparison, I have however found that in reality it
differs in some points so very markedly, that it ought more properly to be re-
garded as a distinct species, for which the specific name obtusifrons is here proposed,
derived from the fact of the total absence of any rostral projection on the front.
Moreover, the urosome appears considerably more elongated in the female, and
the caudal rami are likewise somewhat more produced. On the other hand, the
anterior antenne are comparatively shorter, and in the 2nd pair of legs the inner
ramus is uniarticulate, as in the Ist pair, without any trace of a subdivision.

5 — Crustacea.

30

The male, too, differs conspicuously not only in its small size, but also in the
much more feeble and simple structure of the last pair of legs.

Occurrence.—Specimens of this arctic species were found in some of the
plankton-proofs taken last year during the cruise of the “Michael Sars”. It occurred
at 2 different Stations (Nos. 8 & 9), located in the open sea, about midway
between Iceland and Norway, the depth being recorded to be from 200 to 800
metres. Considering these finding-places, I feel justified in refering the present
species to the fauna of Norway, though it has not as yet been found in the
immediate vicinity of the coast.

Distribution.—The Polar basin crossed by Nansen, in many places rather

abundantly, from the surface down to a depth of 300 metres.

11. Chiridius tenuispinus, G. O. Sars.
(Pl. XVI)
Chiridius tenuispinus, G. O. Sars, The Norw. North Polar Expedition. Crustacea, p. 67, Pl. XVIII.

Specific Characters.—Female.—Body comparatively less slender than in
the 2 preceding species, with the urosome much shorter, scarcely exceeding in
length 1/, of the anterior division. Front projecting below in a sharply-pointed,
but short rostrum. Last segment of metasome produced on each side to a very
slender spiniform process pointing straight behind. Caudal rami comparatively
short, only slightly longer than they are broad, and rounded at the tip. Anterior
antenne, when reflexed, reaching about to the end of the 2nd caudai segment.
Posterior antennee with the inner ramus rather produced and very narrow, though
shorter than the outer. Posterior maxillipeds still more slender than in the 2
preceding species. First pair of legs having the Ist joint of the outer ramus con-
fluent with the 2nd, and without any spine outside. Inner ramus of 2nd pair
distinctly biarticulate, that of the 2 succeeding pairs 3-articulate, with all the
joints well defined. ale unknown. Length of adult female 3.80 mm.

Remarks.—This species, first described by the present author from Nansen’s
Polar Expedition, is closely allied to a form recorded by Dr. Giesbrecht from the
Pacific under the name of Gatdius pungens, and both these forms are unquestionably
congeneric. ‘The northern form differs, however, in the more slender form of the
spiniform projections issuing from the last segment of the metasome, and more
especially in the fact, that the inner ramus of the 2nd pair of legs is distinctly
biarticulate, whereas in the Pacific species it is uniarticulate. In my opinion the
ganus G'atdius can scarcely be supported, as the characters upon which it is

founded, have proved to vary in different species of the present genus. I have

31

hitherto only seen female specimens of this form. The male may undoubtedly be
assumed to exhibit some difference from those of the 2 preceding species, at least
in the structure of the last pair of legs.
| Occurrence.—Some specimens of this form were found in the same
plankton-proofs in which C. obtusifrons occurred (Stats. 8 & 9 of the cruise of
the “Michael Sars”), and moreover at Stat. 34, located considerably farther north,
at some distance east of Jan Mayen, the depth at the last-named Station being
recorded to be from 500 to 1000 metres. Judging from the above-mentioned
occurrences, I think that the present species ought to be referred to the fauna of
Norway, an opinion which has been still further confirmed by recent investigations
of Mr. Nordgaard, who has found a solitary specimen in a plankton-proof taken
in the year 1899 in the Ofoten Fjord.

Distribution.—Not unfrequent at 6 different Stations in the Polar basin
explored by Nansen. At one of the Stations it occurred at the very surface of

the sea, at the others at some depth below the ice.

Gen. 8. Undinopsis, G. 0. Sars, 1884.

Syn: Bradyidius, Giesbrecht, Scott.

Generic Characters.—Body in female comparatively robust, in male somewhat
more slender. Cephalosome, as in the other forms of this family, coalesced with
the Ist segment of metasome, front terminating below in a distinctly bifurcate
rostrum. Last segment of metasome produced on each side to a strong, posteriorly-
pointing projection. Urosome in female comparatively short, in male more slender,
with shortened anal segment. Caudal rami likewise short and of a structure
similar to that in Chiridius. Eye distinct, longitudinal. Anterior antenne in
female not very slender, 24-articulate, with the last articulation well defined,
bristles of the anterior edge unusually strong, partly annulated, and curved in
different directions, those at the tip more or less distinctly ciliated ; same antenne
in male comparatively more slender, with band-like sensory appendages on the
proximal part. Posterior antennse with the rami not very unequal in length.
Oral parts on the whole resembling those in Chiridius; posterior maxillipeds,
however, considerably more robust. Natatory legs very strongly built, inner ramus
of 1st pair uniarticulate, of 2nd pair biarticulate, of the 2 succeeding pairs 3-
articulate. Last pair of legs in male slender, more or less asymmetrical.

Remarks.—This genus was proposed many years ago by the present author,

to include the form erroneously identified by Brady with Pseadocalanus armatus,
Boeck. As, however, no description was given, the generic name Undinopsis was
overlooked, and replaced in 1897 by Dr. Giesbrecht with that of Bradyidius. I
think, however, that I am justified in maintaining the name at first given by me
to this genus. In most of the anatomical details it agrees rather closely with the
genus Chiridius, although differing rather markedly in a few points. The anterior
antennz in the female, for instance, are of a very different appearance, owing to
their much coarser structure and the dense supply of unusually strong bristles,
which give them a peculiar hirsute appearance. In the relative length of the
rami of the posterior antenn, and in the robust form of both the posterior
maxillipeds and the natatory legs this genus also differs conspicuously from
Chiridius. The genus comprises 2 nearly-allied species, both of which exactly
agree in habits, and, unlike what is generally the case with the Calanoida, are

true bottom-forms, never found except close to the ground.

12. Undinopsis Bradyi, G. O. Sars.
(Pl; XUROSER):
Undinopsis Bradyi, G. O. Sars, in Sp. Schneider’s Report of Invertebrata from

the Kyenangen Fjord, 1884.

Syn: Pseudocalanus armatus Brady (not Boeck).
Bradyidius armatus, Giesbrecht, Scott.

”

Specific Characters.— Female. Anterior division of body, seen dorsally,
oval fusiform in shape, greatest width considerably exceeding /; of the length, and
occurring in the middle, both extremities about equally narrowed; seen laterally,
moderately vaulted above, frontal part obtusely truncated anteriorly, and pro-
jecting below to a small, but highly chitinised and distinctly bifurcate rostrum.
Lateral projections of last segment of metasome very strong, mucroniform, and
slightly divergent, reaching beyond the genital segment. Urosome not nearly
attaining '/; of the length of the anterior division, genital segment slightly incras-
sated, though not very protuberant below. Caudal rami scarcely longer than
they are broad, and rounded at the tip, apical sete distinctly biarticulate and
very much elongated, especially the innermost but one. Eye in the living animal
very conspicuous, bright red, and oblong in form. Anterior antennz about the
length of the anterior division of body, all articulations very sharply defined, with
the bristles strongly developed, especially the distal ones, which form together a
dense brush. Posterior antennz with the outer ramus scarcely longer than the
inner. Inner ramus of 2nd to 4th pairs of legs with scattered small spinules on

the posterior face,

33

Male. considerably more slender than female, with the lateral corners
of last segment of metasome far less produced. Urosome very narrow, with
the last segment much shortened; caudal rami generally spread to each side.
Anterior antennz rather slender, with the number of articulations considerably
reduced. Last pair of legs simple, without any trace of an inner ramus, left leg
very slender, right leg rudimentary, scarcely more than '/;-as long as the left, and
3-articulate, last joint conically produced at the tip.

Colour. Body pellucid, with a faint yellowish tinge, and in female varie-
gated with scattered light red patches, partly confluent into transverse bands;
intestine translucent with a dark ochraceous hue; ovaries purple-coloured.

Length of adult female 2.65 mm., of male 2.20 mm.

Remarks.—This is unquestionably the form described by Brady as Pseudo-
calanus armatus, Boeck. Since this identification of Brady has turned out to be
wrong, another specific name should of course have been assigned to the present
species, the more so as the name armatus has been used for two other forms
belonging to the present family, viz., dvtideus armatus and Chiridius armatus. I
therefore think that the name Undinopsis Bradyi, long ago proposed by the present
author for this form, ought to be peferred to that of Bradyidius armatus used
by most other authors.

Occurrence.—I have met with this form in several places on the Nor-
wegian coast, from the Christiania Fjord to Vardg. It is only found close to the
ground in depths ranging from 20 to 40 fathoms, muddy bottom, and accordingly
cannot, as a rule, be taken with the ordinary surface-net, but only by the aid of
the dredge. In order to get specimens in uninjured condition, the dredge must,
however, be of a very light kind and so constructed, that it only sweeps the
bottom, without being filled up with mud. By the aid of such a dredge I have
succeeded in obtaining this form rather abundantly in some places, and have not
infrequently had the opportunity of examining it in the living state. Like most other
Calanoids, it moves in two different manners, now proceeding quite slowly by rapid
vibrations of the posterior antenne and the mandibular palps, now making abrupt
bounds by energetic strokes of the powerful natatory legs. When kept for obser-
vation in a glass bottle with a small quantity of mud, it is always found to keep
close to the bottom, moving about along the mud in a _ horizontal direction.
By far the greater number of specimens obtained are of the female sex. Male
specimens are extremely rare, and seem only to occur at certain seasons.

Distribution.—British Isles (Brady, Scott), Greenland (Vanhéffen).

34

13. Undinopsis similis, G. Q. Sars, n. sp.
(Pl. XXI).

Specific Characters—Female. Very like the preceeding species in external
appearance, though perhaps somewhat more robust of form. Lateral projections
of last segment of metasome comparatively short, scarcely reaching beyond the
middle of the genital segment. Anterior antennze likewise shorter than in U.
Bradyi, not nearly attaining the length of the anterior division, otherwise of a
structure very similar to that of the said species. Posterior antenne with the
outer ramus distinctly longer than the inner. Inner ramus of 2nd to 4th pairs
of legs without any spinules on the hind face.

Male resembling that of the type species; the anterior antenne, however,
less slender, and with all the articulations well defined. Both legs of 5th pair
well developed, and having at the end of the 2nd joint inside a styliform appen-
dage (inner ramus), right leg considerably stronger than left, and terminating in
an incurved claw.

Colour about as in U. Bradyi, though with less distinct pigmentation.

Length of adult female 3.00 mm., of male 2.40 mm.

Remarks.—This form so very closely resembles the type species in its
external appearance, that it may easily be confounded with it, and, indeed, - it
is only quite recently that I have been aware of its specific distinctness. On a
closer examination, however, several well-marked differences are found to exist
in both sexes, proving it to be in reality a well-defined species. Thus in the
female the lateral projections of the last segment of the metasome are far less
produced, and the anterior antennz comparatively shorter. In the male these
antennse are also less slender than in the male of U. Bradyi, differing, moreover,
in the fact that all the articulations are well defined, whereas in the type species
some of them are coalesced. Finally, the last pair of legs in the male exhibit a
very different appearance from those in U. Bradyi, the right leg, which in that
species is rudimentary, being here considerably stronger than the left, both legs
having, moreover, a well-marked rudiment of an inner ramus that is wholly wanting
in the type species.

Occurrence.—I have found this form not unfrequently in the inner part
of the Stavanger Fjord, at Jelsé and Sunde. Like the preceeding species, it
only occurred close to the ground, and was accordingly captured by the aid of
the dredge, the depth ranging from 50 to 100 fathoms. It is very probable, that
this form also occurs in other places upon our coast; but having formerly con-
founded it with U. Bradyi, I am unable at present to state the localities with

certainty.

35

Gen. 9. Bryaxis, Boeck, M. 8.

Generic Characters—Body short and robust, with the anterior division
considerably tumefied. Cephalosome wholly confluent with the Ist pedigerous
segment, and having the lower edges deeply insinuate at the oral region, front
without any trace of a rostrum below. Lateral corners of last segment of meta-
some produced to acute lappets. Urosome nearly as in Undinopsis. Eye wholly
absent. Anterior antennze comparatively short and robust, 24-articulate, and densely
clothed with ciliated bristles. Posterior antenne with the outer ramus poorly
developed. Mandibles with the palp exceedingly large, rami very unequal. Maxillee
and anterior maxillipeds about as in Undinopsis. Posterior maxillipeds very
largely developed, with a peculiar sensory appendage at the end of the 1st basal
joint. Legs of a structure similar to that in Undinopsis. Male unknown.

Remarks.-—This genus, to which the M. 8. name Bryaxis had been applied
by Boeck, is allied to Undinopsis, although it differs rather markedly in the absolute
absence of both rostrum and eye, as also in the structure of the posterior antenne,
mandibles and posterior maxillipeds. It contains as yet only a single species, to
be described below.

14. Bryaxis brevicornis, Boeck, M. S.
(PE Oe XX Ty:

Specific Characters,—Female. Anterior division of body, seen dorsally,
regularly elliptical in outline, greatest width nearly attainmg half the length,
anterior extremity evenly rounded, posterior somewhat contracted; seen laterally,
evenly vaulted anteriorly, front obtuse, without any trace either of a rostrum or
tentacular appendages below, inferior edges of cephalosome remarkably inflexed
in the middle. Lateral lappets of Jast segment of metasome very acute and
obliquely upturned. Urosome scarcely attaining '/; of the length of the anterior
division. Caudal rami short, rounded at the tip, apical sete rather elongated.
Anterior antennze much shorter than the anterior division of the body, all the
articulations Blaply defined and clothed with very strong, ciliated bristles. Posterior
antennee with the outer ramus not even attaining half the length of the inner, and
6-articulate, last joint very small, with the apical sete rudimentary. Inner ramus
of mandibular palp poorly developed, with only 4 apical sete. Sensory appendage
of posterior maxillipeds club-shaped. Colour bright yellow. Length of adult
female 2.60 mm.

36

Remarks.—In the notes on Copepoda left by Boeck this form is named
as above. No description however, has, been published, and the figures accom-
panying the notes are, as far as this form is concerned, copies from some drawings
long ago executed by the present author. It would seem therefore, that Boeck
himself had not observed this Calanoid. . The present form may be at once
distinguished from the others belonging to the family dvtideid@, by its unusually
short and robust body and the comparatively short and densely setiferous anterior
antenne. Moreover, the upturned acute lateral lappets of the last segment of the
metasome distinguish it very conspicuously.

Oceurrence.—I have met with this peculiar Calanoid in several places
off the Norwegian coast, from the Stavanger Fjord to Apelver (Namdal), but
only in greater depths ranging from 50 to 150 fathoms. Like the species of
the genus Undinopsis, it is a true bottom-form, always keeping close to the
ground, and accordingly only to be obtained by the aid of the dredge. I have
several times had an opportunity of observing this form in the living state. It
moves in a peculiar revolving manner, chiefly by the aid of the posterior antenn
and the powerfully developed mandibular palps, only now and then making an
abrupt bound by the action of the natatory legs. All the specimens which I have
seen, are of the female sex. The male, when once detected, wille undoubtedly
exhibit some additional distinguishing character of the present genus. Out of

Norway this form has not yet been observed.

Fam. 6. Euchetide.

Characters.—Cephalosome coalesced with the Ist pedigerous segment, or
at any rate imperfectly defined from it, front projecting in an acute, undivided
rostrum. The last 2 segments of metasome united. Urosome consisting in female
of 4 segments, the last of which, however, is very small, genital segment more
or less protuberant below. Caudal rami short, with the outermost marginal
seta rudimentary, appendicular bristle issuing from the inner corner of the rami,
and generally much elongated. Anterior antenne slender, with some of the bristles
of the anterior edge very long and extending in different directions; those of
male provided at the base with strongly developed sensory appendages. Posterior
antennss and mandibles normal. Maxille with the palp incurved in an unusual

manner. Both pairs of maxillipeds very powerfully developed; the posterior ones

aM,

especially unusually strong, with the terminal part reflexed and armed with long
claw-like spines. Oral parts in male much degenerated. Natatory legs power-
fully developed, and on the whole resembling in structure those in the dttideide.
5th pair of legs wholly wanting in female, those in male exceedingly large and
powerful. Ovisae present in female.

Remarks.—This family as yet only comprises a single genus, viz., Hucheta,
Philippi, which, however, exhibits some very conspicuous structural differences from
the other Amphascandria. The genus was also regarded by Dr. Giesbrecht as
the type of a particular subfamily, Huchetine, which I now propose, in accordance

with the plan followed in this account, to raise to the rank of a true family.

Gen. 10. Eucheeta, Philippi, 1852.

Generic Characters.—Body comparatively slender, especially in the male,
with the cephalosome attenuated in front, rostrum pointing in female obliquely
forwards, in male more downwards, and having at the base in front a more or
less projecting ledge. Lateral corners of last segment of metasome rounded off,
and generally densely clothed with hairs below. Urosome, as arule, more elongated
than in the dtideid@, genital protuberance in female very prominent, and of
different form in the different species. Caudal rami in female firmly connected
with the last caudal segment, in male mobile, marginal sets spread in a fan-like
manner and beautifully plumous, the innermost but one much longer than the
others, appendicular bristle generally very slender, hair-like and geniculate at the
base. Eye small, subventral. Anterior antenne in female 24-articulate, 3rd, 7th,
8th and 13th articulations each carrying an unusually long bristle at the end
anteriorly; terminal articulation very small, with a long reflexed seta on the tip.
Hpistome produced in front of the anterior lip to a knob-like, densely hirsute
projection. Anterior maxillipeds with the spines of the terminal part very strong,
claw-like. Posterior maxillipeds with the 2nd basal joint very large, fusiform,
attenuated distally. Both pairs in male much reduced in size. Ist pair of legs
much smaller than the others, and having the first 2 joints of the outer ramus
confluent in female. Inner ramus of the first 2 pairs of legs uniarticulate, of the
2 succeeding pairs 3-articulate. Both legs of last pair in male well developed;
right leg with a long styliform inner ramus, outer ramus biarticulate, with the
distal joint claw-like; left ieg terminating in a complicated hand, by which the
‘ spermatuphore is seized.

6 — Crustacea.

38

Remarks.—This genus was established in the year 1852 by Philippi, to
comprise the Mediterranean form recorded by Prestandrea as Cyclops marinus.
Subsequently several additional species have been described, some of which,
however, have justly been removed by. Dr. Giesbrecht, and referred to particular
genera of the family €tideide. A considerable number of species are still left,
amounting to about 16 in all. To the Norwegian fauna belong 3 species, to be
described below, all of which are remarkable from their large size, representing

in fact the largest known Calanoids.

15. Eucheta norvegica, Boeck.
(Pl. XXIV, XXV, XXVI).
Eucheta norvegica, Boeck. Nye Slegter og Arter af Saltvandscopepoder. Chr. Vid. Selsk.
Forh. 1872, p. 40.

Syn: Hucheta Prestandree, Boeck (not Philippi).

ne — carinata, Moebius.

Specific Characters.—Female. Form of body rather slender. Anterior
division, seen dorsally, oblong fusiform in outline, greatest width about equalling
'/s of the length, anterior extremity considerably more narrowed than the posterior.
Cephalosome faintly defined from the Ist pedigerous segment, rostral ledge but
slightly prominent. Lateral lobes of last segment of metasome somewhat produced
and narrowly rounded, exhibiting at the tip a small nodiform projection. Urosome
unusually slender, exceeding half the length of the anterior division, genital seg-
ment with the proximal part rather narrow, carrying 2 small juxtaposed tubercles
below, genital protuberance very large and thick, proceeding from the hind part of
the segment, and at right angles to it, tip blunted and exhibiting on each side a small
projecting lobule. The 2 middle caudal segments of about equal size and minutely
hairy. Caudal rami about the length of the last caudal segment, and obliquely
oval in form, inner corner drawn out to a conical process carrying the appen-
dicular bristle; the latter exceedingly slender, almost attaining the length of the
whole body, and distinctly geniculate at the base; marginal sete very densely
plumous, the innermost but one considerably longer than the others, which are
nearly equal in length. Anterior antenne slightly exceeding in length the anterior
division of the body, the proximal articulations finely hairy on the posterior edge.

Male exceedingly slender in form, with the cephalon and 1st pedigerous
segment wholly coalesced, rostrum deflexed. Urosome narrow cylindric in form,
and, as usual, 5-articulate, last segment, however, almost obsolete, hind edge of
the 2 middle segments divided into delicate flattened denticles. Caudal rami more

rounded than in female, and movably articulated to the last segment, appendicular ‘

oe Fe

bristle comparatively short. Anterior antennze somewhat thickened at the base,
and only 22-articulate. Masticatory part both of the mandibles and maxille
obsolete. Anterior maxillipeds extremely small and rudimentary. Posterior max-
illipeds likewise much smaller than in female, spines of the terminal part trans-
formed to flexible ciliated sete. Ist pair of legs with the outer ramus distinctly
3-articulate. Last pair of legs considerably exceeding the urosome in length, left
leg with the hand shorterethan the preceding joint and slightly widening distally,
with the inner edge coarsely dentate, thumb produced to a sharp unguiform point,
dactylus short, with a brush of hairs inside the tip, appendicular lappet obtusely
rounded.

Colour. Body pellucid, with the oral region more or less deeply tinged
with crimson; ova in the ovisac dark blue. Caudal sete with the cilia beautifully
iridescent.

Length of adult female about & mm., of male 7 mm.

Remarks.—This form was first recorded by Boeck from the Norwegian
coast, but at first erroneously identified with EL. Prestandrew, Philippi (= E. marina
Prestandrea), which species does not occur in the northern Ocean. The form
recorded by Moebius as FE. carinata, is unquestionably identical with Boeck’s
species. On the other hand, the form described and figured by the present
author, in his account of the Crustacea of the Norwegian North Atlantic Expedition,
as EH. norvegica, Boeck, is not that species, but a nearly allied form, H. barbata,
Brady; and the form recorded from Nansen’s Polar Expedition under the same
name, has also, on a closer examination, turned out to be a different species, viz.,
E. glacialis, Hansen. Both these species are now proved to belong to the fauna
of Norway, and will be described below. ‘The present species is chiefly charac-
terised by its unusually slender body, the form of the genital protuberance in the
female, and the structure of the hand in the last left leg of the male.

Occurrence.—I have found this handsome Calanoid rather frequently along
the whole Norwegian coast, from the Christiania Fjord to Vadsé, especially in
the great depths of the fjords. At times, however, it also ascends nearer to the
surface, and in the several proofs of plankton taken during the cruise of the
“Michael Sars” in the open sea, it was by no means unfrequent. Male specimens
are not infrequently found, and are at once recognized by their extremely slender
body and the largely developed last pair of legs.

Distribution.—Occeasional in two different places in the polar basin crossed

by Nansen,

16. Eucheta glacialis, Hansen.
(Pl. XXVID).

Eucheta glacialis, Hansen. Oversigt over de paa Dijmphna-Togtet indsamlede Krebsdyr,
p. 74, Pl. XXIII, figs. 5—5K, Pl. XIV, figs. 1—1d.

Syn: Eucheta norvegica, G. O. Sars (part).

Specifie Characters.—Female. Very like the preceding species in its external
appearance, though of larger size and somewhat more robust form of body. Ce-
phalosome not defined from the Ist pedigerous segment by any perceptible
demarcation, form of rostrum as in FE. norvegica. Lateral lobes of last segment
of metasome slightly angular, but without any tuberculiform projection at the tip.
Urosome comparatively shorter, not nearly attaining half the length of the anterior
division, genital protuberance issuing from about the middle of the segment, and
broadly conical in form, extending somewhat obliquely behind, tip provided on
each side with 2 narrowly rounded lobules. Outer caudal segments minutely
hairy. Caudal rami comparatively shorter than in H. norvegica and less oblique,
appendicular bristle not exceeding in length the marginal sete, and_ slightly
flexuous at the base, the innermost but one of the caudal sete almost twice the
length of the others. Structure of the several appendages almost exactly as in
EH. norvegica.

Male likewise closely resembling that of the said species, though perhaps
somewhat less slender of form, and differing in the structure of the hand of the
last left leg, the thumb of which has the form of an oblong quadrangular plate
closely crenulated along the edges, and transversely truncated at the tip.

Colour more or less bright red.

Length of adult female about 10 mm., of male 8 mm.

Rtemarks.—This form was first described by Dr. Hansen in the above-
quoted paper. I did not, however, at first recognise its specific difference from
i. norvegica, and it was therefore, in my account of the Crustacea of Nansen’s
Polar Expedition, only quoted as a synonym to that species. The closer examina-
tion which I have recently instituted, however, has led to the result, that Dr.
Hansen’s species ought to be maintained, though it certainly comes very near to
EK. norvegica. The chief differences consist in the somewhat more robust form of
the body, the more conical genital protuberance in the female, and the rather
different structure of the thumb in the left last leg of the male. It also attains a
considerably larger size, some of the specimens even exceeding 10 mm. in length.

Occurrence.—In the immediate neighbourhood of the Norwegian coast
this form has not yet been met with, I have, however, recently found it in 3

ae

of the plankton-samples taken during the cruise of the “Michael Sars” in 1900,
two of which were from the Norwegian Sea, the one (St. 9) about midway between
Iceland and Norway, the other farther north, at some distance east of Jan Mayen,
the depth at the first-named Station being recorded to be from 200 to 400 metres,
at the last-named from 500 to 1000 metres.

Distribution.—The Kara Sea (Hansen), Polar basin crossed by Nansen,
rather abundant in many places, from 300 metres up to the very surface of the

sea (the present author).

17. Eucheta barbata, Brady.
(Pl. XXVIII).

Eucheta barbata, Brady. Report on the Copepoda of the Challenger Expedition,
p. 66, Pl. XXII, figs. 6—12.

Syn: Kucheta norvegica, G. O. Sars (part).

Specific Characters.— Female. General form of body closely resembling
that of KH. glacialis. Cephalosome wholly coalesced with the Ist pedigerous seg-
ment, rostrum as in the 2 preceding species; epistomal protuberance very densely
hirsute. Lateral corners of last segment of metasome broadly rounded off and
densely hairy below. Urosome not nearly attaining half the length of the anterior
division, genital protuberance comparatively less prominent than in the 2 preceding
species, and issuing from the anterior part of the segment, apical lobules very unequal,
the anterior ones being much larger than the posterior and recurved in a beaklike
manner. Outer caudal segments densely clothed with hairs, which, especially on
the ventral face, are rather long and to some extent arranged in fascicles. Caudal
rami comparatively short and likewise densely hairy on both edges; innermost
but one of the caudal sete almost twice as long as the others; appendicular
bristle, as in EL. norvegica, very much elongated, and distinctly geniculate at the
base. Antenne, oral parts, and legs scarcely differing in their structure from
those parts in the 2 preceding species.

Male exhibiting the same differences from the female as in the 2
preceding species. Hand of left last leg, however, somewhat different, the thumb
not being produced at the end, but coarsely denticulated along the inner edge,
2 of the denticles larger than the others, dactylus as in the 2 preceding species,
appendicular lobe, however, narrower, cylindric in form and hamiformly curved
at the tip.

Colour bright red.

Length of adult female reaching to 12 mm., of male to 10 mm,

42

Remarks.—It is with considerable hesitation that I refer this form to Brady’s
species. I cannot, however, in the rather imperfect description and figures given
by that: author, find any essential difference which would forbid such an identi-
fication. In its general appearance this form closely resembles F/. glacialis, from
which species it is, however, at once distinguished by the rather different form
of the genital protuberance in the female, as also by the great length of the
appendicular bristle of the caudal rami, in which latter respect it agrees with L.
norvegica. The dense hispidity of the outer caudal segments in the female likewise
furnishes an easily recognizable character. In the male the hand of the left last
leg looks somewhat intermediate in structure between that of the last-named species
and of FE. glacialis, the thumb resembling in form that in /. glacialis, whereas its
armature more closely agrees with that in £. norvegica. This form is perhaps the
largest of all known Calanoids, its size even exceeding that of EF. glacialis.

Several well-preserved specimens of this magnificent form

Occurrence.
were found in the above-mentioned plankton-sample from St. 34 of the cruise of the
“Michael Sars”. A single specimen, moreover, occurred in another plankton-sample
taken at Stat. 46, at some distance west of the Lofoten Islands. The same species
was also procured during the Norwegian North Atlantic Expedition by the aid of
the trawl in several places in the Norwegian Sea, and always in great depths,
down to 2000 fathoms. The figures given in my account of the Crustacea of that
Expedition refer to this species, and not to E. norvegica. In the Polar basin
crossed by Nansen, this form did not occur.

Distribution.—South Atlantic Ocean in lat. 36° 44’ S., long. 46° 16’ W.,
depth 2650 fathoms (Brady).

Fam. 7. Phaénnide.

Syn: Scolecithricine, Giesbrecht (part).

Characters.—Form of body, as a rule, rather robust, with the anterior
division more or less tumefied. Cephalosome coalesced with the 1st pedigerous
segment or imperfectly defined from it; frontal part rounded, rostral prominence
with or without tentacular appendages. Last segment of metasome more gene-
rally defined from the preceding one. Urosome comparatively short, with the

genital segment in female not very protuberant below, last segment small. Kye

43

generally double. Anterior antenne in female of moderate length or compara-
tively short, 23- or 24-articulate; those of male with the usual supply of sensory
appendages, and having some of the articulations confluent. Posterior antenne
with the outer ramus generally longer than the inner, and 6-articulate. Oral parts
on the whole normal, except the anterior maxillipeds, which are rather short and
clearly characterised by the peculiar transformation of the sets of the terminal
part into extremely delicate, incurved cylindric appendages terminating in a brush
of fine ciliz. ~ Natatory legs strongly built, and of a structure similar to that in
the dtideide. 5th pair of legs in female generally present, though rather small,
triarticulate, not natatory; those in male comparatively simple, left leg the longer.

Remarks.—This new family is established to comprise some genera referred
by Dr. Giesbrecht to his subfamily Scolecithricine, for which the genus Scolecithrix
of Brady is the type. As, however, the species referred to the latter genus in
reality belong to several distinct genera, I have felt justified in comprising those
genera in a separate family, Scolecithricidw, to be treated of farther on. The chief
character of the present family consists in the peculiar transformation of the sete
of the terminal part of the anterior maxillipeds to extremely delicate penicillate
appendages, not found in any of the preceding families. In other respects, the forms
belonging to this family recall, both in their external appearance and in several of
the structural details, that of the dtideida. Whereas, however, in the latter family
the 5th pair of legs are always wanting in the female, these legs are generally
present, though in a rudimentary state, in the Phaénnide. We know at present
of 3 distinct genera belonging to this family, viz., Phaénna, Claus, Pseudophacnna,
G. O. Sars, and Xanthocalanus, Giesbrecht. Of these the 2 last-mentioned are
represented in the fauna of Norway.

Gen. 11. PSeudophaénna, G. O. Sars, n.

Generie Characters.—Body comparatively short and stout, with the anterior
division considerably tumefied. Cephalosome completely coalesced with the Ist
pedigerous segment, frontal part rounded and projecting below in an undivided
rostrum, obtuse at the tip. Last segment of metasome very small, but distinctly
defined from the preceding one, lateral lobes but slightly produced. Urosome in
female comparatively short, 4-articulate, in male more slender, last segment in
both sexes rather small. Caudal rami short, obtusely rounded at the tip, apical

sete rather elongated, appendicular bristle small. Eye consisting of two closely

44

approximate halves. Anterior antennze comparatively short and rather densely
setiferous, consisting in female of 23 articulations. Posterior antennze with the
outer ramus very large, inner poorly developed, with the apical setze much reduced
in number. Mandibles well developed, with the teeth of the masticatory part
strong and partly bidentate. Exopodite of maxille very small, bisetose. Anterior
maxillipeds with all the spines of the basal part of the same structure though of
different length, and very flexible. Posterior maxillipeds rather powerful, with
the 2nd basal joint fusiformly dilated, terminal part comparatively short. Oral
parts in male considerably reduced. Natatory legs strongly built, inner ramus
with no spinules on the hind face. 5th pair of legs in female very small, with
the terminal joint simple, digitiform; those in male with both legs well developed.

Remarks.—This new genus is somewhat intermediate between Phaénna
and Xanthocalanus, agreeing with the former in the robust form of the body,
with the latter in the presence in the female of distinct, though very small legs
of 5th pair. From both these genera it differs very markedly in several of the
structural details, though in the peculiar transformation of the apical sets of the
anterior maxillipeds it exactly agrees with both of them. The genus at present

only contains a single species, to be described below.

18. Pseudophaenna typica, G. O. Sars, n. sp.
(PIE Bem Ree

Specific Characters.—Female. Anterior division of body, seen dorsally,
regularly oval or elliptical in outline, greatest width about equalling half the length,
anterior extremity narrowly rounded, posterior somewhat contracted. Cephalosome
with the dorsal margin forming a quite even curve up to the tip of the rostrum; the
latter conical in form and pointing straight downwards. Last segment of metasome
very small, with the lateral lobes narrowly rounded. Urosome scarcely attaining
"/; of the length of the anterior division, genital segment about the length of the
2 middle segments combined. Caudal rami a little longer than they are broad,
and scarcely at all divergent, innermost but one of the apical sets longer than
the others. Anterior antenne scarcely longer than the anterior division of the
body, and rather densely setous, all the articulations sharply defined. Posterior
antenne with the outer ramus more than twice as long as the inner, terminal
joint of the latter with only 3 or 4 sete on each of the lobules. Posterior max-
illipeds with the 2nd basal joint almost twice as long as the 1st, and considerably
dilated in the middle, terminal part scarcely half as long, and more or less incurved,
with the 2 outer joints very small, procurved sete of the preceding ones very

45

strong, spiniform. Last pair of legs extremely small, though distinctly 3-articulate,
basal joint rather thick and armed at the end inside with densely crowded spinules,
last 2 joints unarmed, middle one very short, terminal joint straight, digitiform.

Male not differimg much from female in its external appearance, though
having the urosome considerably more slender, and, as usual, 5-articulate. Anterior
antenne consisting of only 21 articulations. Both pairs of maxillipeds consider-
ably transformed, the anterior ones very small, the posterior ones with the terminal
part reflexed. Last pair of legs very slender, right leg 5-articulate and reaching
beyond the antepenultimate joint of left.

Colour dark yellowish brown.

Length of adult female 1.60 mm., of male 1.40 mm.

Remarks.—In its general appearance this Calanoid somewhat recalls the
Astideid described above as Bryaxis brevicornis, Boeck, having a similar robust
form of body and also comparatively short and densely setous anterior antenne.
On a closer examination, however, it is found to differ very essentially, so that
it cannot even be included in the same family. It also somewhat resembles the
Mediterranean form, Phaénna spinifera, Claus; but this Calanoid has the body
still more robust, whereas its anterior antenne are considerable more slender.

Occurrence.—I have found this peculiar Calanoid occasionally in several
places on the Norwegian coast, from the Christiania Fjord to Vardé, and always,
like the species of the genus Undinopsis, only close to the ground in depths ranging
from 20 to 50 fathoms. It accordingly is a true bottom-form, unlike what is
generally the case with the Calanoida. Out of Norway this form has not yet
been found.

Gen. 12. Xanthocalanus, Giesbrecht, 1892.

Generic Characters.—Body less robust than in the preceding genus, with
the cephalosome more or less distinctly defined from the Ist pedigerous segment,
rostral prominence with 2 soft posteriorly-pointing tentacular appendages. Lateral
lobes of last segment of metasome produced to more or less prominent acute
lappets. Urosome short, of a structure similar to that in the preceding genus.
Two eyes present, separated by a distinct interspace. Anterior antennee in female
rather slender, 24-articulate, bristles of anterior edge not very strong, 2 of them
issuing from the basal joint finely plumose; those of male richly supplied with
sensory appendages, and having some of the articulations coalesced. Posterior

7 — Crustacea.

46

antennze with the inner ramus well developed, though somewhat shorter than the
outer. Mandibles comparatively narrow, with the teeth of the masticatory part
simple. Maxille normal. Anterior maxillipeds with each of the 2 outer digitiform
lobes carrying a strong, claw-like spine, coarsely denticulate inside. Posterior
maxillipeds rather slender. Inner ramus of 2nd to 4th pairs of legs armed on
the hind face with oblique rows of rather strong spinules. Last pair of legs in
female with the terminal joint spiniferous; those of male comparatively simple,
left leg very slender, right rudimentary or wanting. /

Remarks.—This genus was established in the year 1892 by Dr. Giesbrecht,
to comprise 2 supposed species from the Mediterranean, viz., X. agilis and minor.
In my opinion, however, the latter species ought to be discarded, being apparently
only founded upon immature specimens of the former. The genus is easily
distinguished both from Phaénna and Pseudophaénna by the less robust form of
body, the structure of the rostral part, and the acutely produced lateral lobes
of the last segment of the metasome. Moreover, the 2 strong and coarsely dentate
spines on the anterior maxillipeds are rather characteristic, as also the structure
of the last pair of legs in both sexes. Two well-defined, though closely allied
species, to be described below, belong to the fauna of Norway.

19. Xanthocalanus borealis, G. O. Sars.
(BIS XX, XSLT):

Xanthocalanus borealis, G. O. Sars. Crustacea of the Norwegian North Polar Expedition,
ide 2h), Blo de

Specific Characters.—Female. Anterior division of body, seen dorsally,
oblong oval in form, greatest width not attaining half the length, anterior extremity
narrowly rounded, posterior slightly contracted. Cephalosome evenly vaulted above,
and defined from the Ist pedigerous segment by a faint curved suture. Last
segment of metasome completely coalesced with the preceding one, lateral lobes
drawn out to acute, posteriorly-pointing lappets reaching in adult specimens beyond
the middle of the genital segment. Urosome scarcely exceeding */; of the length
of the anterior division, genital segment fully as long as the 2 succeeding ones
combined. Caudal rami very short, scarcely longer than they are broad, apical
setze much elongated, especially the innermost but one, and somewhat divergent.
Anterior antenne very slender, when reflexed reaching about to the end of the
genital segment. Posterior antenne with the outer ramus but slightly exceeding
the inner in length. Spinules on the hind face of the inner ramus in 2nd and
3rd pairs of legs regularly disposed in a single oblique row, those in 4th pair

47

more irregularly arranged, and wanting on the last joint. 5th pair of legs some-
what curved, with the inner edge of the basal joint densely spinulose, 2nd joint
conspicuously dilated in the middle, almost globose, and slightly spinulose inside,
terminal joint about the same length but much narrower, and armed in mature speci-
mens with 4 short ciliated spines, 2 apical and 2 lateral. These legs in younger
specimens of rather different appearance, the 2 outer joints being confluent to
an angularly curved piece carrying only 3 spines on the tip.

Male considerably smaller than female and of more slender form, with
the lateral lobes of last segment of metasome less prominent. Urosome very
narrow, and comparatively longer than in female, caudal rami mobile. Anterior
antennze modified in the usual manner. Oral parts less rudimentary than in most
other Amphascandria. Left leg of last pair exceedingly slender, with the 4th
joint very narrow, linear, and longer than the last 2 joints combined; right leg
distinctly developed, though very small, reaching about to the end of the 2nd
joint of the left.

Colour. Body in both sexes whitish, pellucid, tinged in some places with
a slight reddish pigment.

Length of adult female 3.50 mm., of male 2.50 mm.

Remarks.—This form was first described by the present author from a
somewhat defective female specimen procured during Nansen’s Polar Expedition.
The apparent differences in the general form of the body, and especially in the
structure of the last pair of legs, between the polar specimen and the Norwegian
form here described, may be accounted for by the circumstance that that specimen
was not fully mature, though of rather large size. I have found similar differences
in young specimens of the Norwegian form. The present species is easily dist-
inguished from the type species, X. agilis, Giesbrecht, both by its much larger
size and by several other characters, for instance, the presence in the male of a
right leg in the last pair.

Occurrence.—I have found this form not infrequently in the Stavanger
Fjord, at Jelsé and Sunde, as also in a few other places off the west coast of
Norway. The specimens were only procured by the aid of the dredge from very
considerable depths, down to 400 fathoms, where it occurred together with Chiri-
dius armatus, Boeck. The character of this Calanoid as a relict arctic form has
been proved by the occurrence of a specimen of apparently the same species in
the Polar Sea, at a far less depth.

Distribution.—Polar basin, north of the New Siberian Isles (a solitary

young female specimen).

48

20. Xanthocalanus propingvus, G. O. Sars, n. sp.
(Pl. XXXIID.

Specific Characters—Female. Form of body resembling that of the pre-
ceding species, though somewhat less slender. Last segment of metasome defined
from the preceding one by a distinctly marked suture, lateral lappets compara-
tively shorter than in X. borealis, scarcely reaching to the middle of the genital
segment. Urosome about '/; as long as the anterior division of the body;
caudal rami longer than they are broad. Anterior antenne very slender, reaching
when reflexed, to the end of the 2nd caudal segment. Posterior antenne with
the outer ramus considerably longer than the inner. Oral parts almost exactly
as in the preceeding species. Natatory legs likewise of a very similar structure,
except that the spinules on the inner ramus of the 4th pair are arranged in a
single oblique row. Last pair of legs comparatively shorter and more robust,
basal joint coarsely spinulose inside, 2nd joint of about same breadth throughout,
last joint much shorter and rather broad at the base, carrying an oblique row
of 4 spines, the innermost of which is much coarser than the others.

Male resembling that of the preceding species, though somewhat differing
in the structure of the last pair of legs, which are very asymmetrical, the right
leg being extremely reduced in size, scarcely even reaching to the middle of the
1st joint of the left one.

Colour whitish, pellucid, without any conspicuous pigment.

Length of adult female 1.75 mm.

Remarks.—This form is closely allied to the preceding species, but of
much smaller size, and somewhat less slender of form. It may, moreover, be
easily distinguished by the well-marked separation of the last segment of the
metasome from the preceding one, as also by the somewhat different structure of
the last pair of legs in both sexes.

Occurrence.—Several specimens of this form were collected many years
ago by the present author at Selsévig on the Nordland coast, located just within
the Polar circle. They were procured by the aid of the dredge from a depth of
about 100 fathoms. This species also occurs occasionally off the west coast of
Norway, some few specimens having recently been found among those of X. borealis

collected in this region.

Atideide.

G.0. Sars autogr.

Copepoda

Calawercde:.

)

Chiridius obtusifrons, G. 0. Sars.

PL XVIL

Trykt iden private Opmaaling, Chra.

4-5
EEE ee ee

PI. XVII.

Copepoda

Calanorda.

Atideids.

2 fl RO RL
Ob Yee i ee
CSE
-

SOF
Looe
<

Tryktiden private Opmaaling, Chra

6.0. Sars autogr.

Chiridius tenuispinus, G. 0. Sars.

PES

——

_ j SS CZ iy :

ENO Waa me

Copepoda
Calanorda.

1 aaa |
ee

Atideide.

|
|

Tryktiden private Opmaaling,Chra

< SS

Brady, G. 0. Sars.

ens S : :
Pt ea a eee
: OSS

YY / 4a Jy
via net

~~

Undinopsis

6.0. Sars autogr.

PI. XX.

pepoda
Calanorda.

Ore

Atideide.

Tryktiden private Opmaaling, Chra

Bradyi , G. 0. Sars.

(continued)

Undinopsis

6.0. Sars autogr.

Ajede.

6.0. Sars autogr.

Copepoda

Calanorda.

Undinopsis similis, G. 0. Sars.

PI. XXII.

Tryktiden private Opmaaling, Chra.

Toh we

Og eee Ree gee ek

ope

Copepoda
Calanoida.

Tryktiden private Opmaaling, Chra

5
( |
[eb)
(ep)
on
@
foe
—
Oo
qo
>
wo
(oe
oO
cA
~<
a
ire)
I
mm
fe)
5
n
fH
tw
(da)
a)
wo

PL XXO

Copepoda
Calano:rda

Atide: de

VE ee
yes
\ f-

Ye

ie
Us
——

rie

Trykt i den private Opmaaling, Chra.

Boeck -

brevicornis,
(continued)

Bryaxis

6.0. Sars autogr.

Copepoda
PI. XXIV.

Euchastida.

Calanoida.

ae
LL,

— |

Ry
en |

ig

romero aes

:
i

—— “ — ANS
, FRE ASATNN
SMMAVVO_SETA

4a)
NN
\

ZZ
VC

ANH

ee
tr

6. 0. Sars autogr.

Tryktiden private Opmaaling Chra

norvegica, Boeck

Eucheta

Calanord a: PESO

Copepoda

Euchestida.

|

Tryktiden private Upmaaiing. Chra

6.3. Sars auto gr.

Eucheta norvegica, Boeck.

continued,

f
{
\

Copepoda
Calanorda.

Euchestida.

——
“SSE ES

Trykti den private Dpmaaling, Cnra

Ss

. BS
SEE SS

<a — LL

6.0 Sars autogr.

norvegica, Boeck

Euchasta

(male)

ee

PLXXVI.

epoda

Pp
Calanoreda

Co

Euchetida.

uy \\

\

Tryktiden private Opmaaling, Chra.

6.0. Sars autogr

Euchata glacialis, Hansen

PLXXVII.

Ida.

anol

21

Copepoda
é

da.

°

Euchest

Tryktiden private Opmaaling, Chra

6.0. Sars autoqr.

barbata, Brady.

Eucheta

Copepoda
Calaneraa.

PLS

Phaennida

Tryktiden private Opmaaling, Chra

typica, G.0.Sars.

Pseudophaenna

G.0.Sars autoar.

Catanorda. ie OR

Copepoda

Phaennida

—< os

xX

private Opmaaling Chra

ktiden

G.0. Sars auto gr.

Pseudophaenna typica, G.Q.Sars.

(continued)

Calan orca: Bia Oe a

Copepoda

Phaennida

——

ze
ETE es

se

iryktiden private Opmaaling, Chra.

G.0. Sars autoar

Xanthocalanus borealis, G.0.Sars.

PI XXXII.

pepoda
Calanorda.

iO

Phagnnide

Tryktiden private Opmaating, Chra.

6.0. Sars autogr.

Xanthocalanus borealis, G.0.Sars.

(continued)

i

AN ACCOUNT

OF THE

CRUSTAGEA

OF

NORWAY

WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES
BY

G. O. SARS

VOL. IV

COPEPODA
CALANOIDA

PART V & VI

SCOLECITHRICIDA, DIAIXIDA, STEPHIDA, THARYBIDA,
PSEUDOCYCLOPIID Ai

WITH 16 AUTOGRAPHIC PLATES

BERGEN

= PUBLISHED BY THE BERGEN MUSEUM
- §OLD BY
ALB. CAMMERMEYER’S FORLAG, CHRISTIANIA
1902

Ag

Fam. 8. Scolecithricide.

Characters.—Body of somewhat varying form, sometimes rather short and
robust, sometimes more slender. Cephalosome coalesced with the 1st pedigerous
segment, front carrying below 2 more or less distinct soft tentacular appendages.
Last 2 segments of metasome generally united. Urosome, as a rule, short, 4-arti-
culate in female, 5-articulate in male. Caudal rami short, with only 4 apical sete.
Eye small, simple. Anterior antenne more or less slender, 19—23-articulate,
with the outer 2 joints not distinctly defined; those in male transformed in the
usual manner. Posterior antenne with the outer ramus 6-arviculate. Masticatory
part of mandibles and maxilla not very strong. Anterior maxillipeds compara-
tively small, with the sete of the terminal part transformed to delicate sensory
appendages, which are either all vermiform or some of them pedicellate, termin-
ating in a knob-like dilatation. Posterior maxillipeds slender, with the terminal
part reflexed. Oral parts in male more or less transformed. Natatory legs
powerfully developed, and generally spinulous on the hind face, inner ramus of
1st pair uniarticulate, of 2nd pair biarticulate, of 3rd and 4th pairs 3-articulate.
5th pair of legs sometimes wanting in female, but more frequently present, though
of rather simple structure; those in male comparatively slender and rather asym-
metrical.

Remarks.—In this family I propose to comprise the several forms referred
by other authors to the genus Scolecithriv of Brady. There cannot, in my opinion, *
be any doubt that some at least of these forms ought to be generically separated
from each other, as they differ in several very essential] characters, e. g. in the
presence or absence of the last pair of legs in the female, and in the structure
of these legs in the male. Another character has been called attention to by
Mr. Th. Scott, viz., the different development of the terminal appendages to the
anterior maxillipeds. I think we must admit at least 4 different genera, viz.,
Scolecithrix, Brady; Lophothrix, Giesbrecht; Amallophora, Scott, and Scolecithii-
cella, G. O. Sars. Of these genera, only the 2 Jast-mentioned are represented in
the fauna of Norway.

8 — Crustacea.

Gen. 13. Amallophora, Scott, 1894.

Syn: Scolecithrix, Giesbrecht (part).

. Scaphocalanus, G. O. Sars.

Generic Characters.—Body more or less slender, and of very different
appearance in the two sexes. Cephalosome in female attenuated anteriorly, and
sometimes exhibiting in front a distinct crest wholly wanting in male; rostral
prominence very small and undivided, tentacular appendages exceedingly delicate
and filiform. Last segment of metasome united with the preceding one. Urosome
less abbreviated than in most other forms, genital segment in female compara-
tively short and scarcely at all protuberant below, caudal sete rather unequal,
the innermost but one being much longer than the others. Anterior antennie
in female consisting of 23 articulations, of which the first 2 are unusually large
and sharply marked off from the succeeding ones; those in male rather slender
and angularly curved in the middle, with some of the articulations coalesced.
Posterior antenne with both rami slender and elongated, especially the inner one.
Mandibles with the 3 outer denticles of the cutting edge of the same appearance,
bidentate, palp with the outer ramus exceedingly large, inner comparatively small.
Anterior maxillipeds with the 3 outer appendages of the terminal part vermiform,
the remaining 5 shorter and each terminating in a bud-like dilatation (amalla).
Oral parts in male considerably transformed. Ist pair of natatory legs com-
paratively small, the succeeding ones very powerfully developed, with the mner
ramus coarsely spinulous on the hind face; terminal spime of outer ramus strong,
serrate outside. Last pair of legs in female distinctly developed, biarticulate or
imperfectly triarticulate, last joint fusiform, with a slender denticulated spine
inside, a very short one outside, and a somewhat longer one at the tip; those
in male not very large, and rather asymmetrical, right leg with the 2nd basal joint
creatly tumefied in its proximal part, and carrying inside a styliform appendage
(inner ramus), its distal part attenuated and carrying at the tip a comparatively
short 3-articulate appendage (outer ramus); left leg with the 2nd basal joint
narrow cylindric, terminating in 2 subequal 3-articulate rami.

Remarks.—In the year 1894, the well-known Scotch naturalist, Th. Scott,
published a most interesting Report on the Entomostraca collected during the
expedition of the Telegraph Steamer “Buccaneer” in the gulf of Guinea. Among
the numerous forms of Calanoids procured, there were some species, which,
though on the whole exhibiting the characters of the genus Scolecithrix of Brady,

diftered very conspicuously in the peculiar transformation of some of the terminal

bil

appendages to the anterior maxillipeds. These species were comprised within a
particular sub-genus, to which the above-mentioned name was assigned. In my
opinion, this sub-genus ought certainly to be raised to the rank of a true genus,
as it also exhibits in several other respects well-marked differences from the type
of the genus Scolecithrix, S. dane (Lubbock). One of the species included in
this genus, viz., A. typica, Scott, has since been removed by Dr. Giesbrecht,
who considers it to be the male of a species of the genus Xanthocalanus. The
other 3 species are, however, undoubtedly congeneric, and one of them, A. magna,
Scott, I now consider to be identical with the form I have described from
Nansen’s Polar Expedition as Scaphocalanus acrocephalus. Another polar form,
likewise described in my Account of the Crustacea of that Expedition, viz., Scoleci-
thrix brevicornis, has turned out, on a closer examination, to belong to the same
genus. According to more recent investigations, both these forms are referable

to the fauna of Norway, and they will therefore be described below.

21. Amallophora magna, Scott.
(Pl. XXXIV & XXXY).
Amallophora magna, Th. Scott. Report on Entomostraca from the Gulf of Guinea. Transact.

Linn, Soc. London, Vol. IV, Part I, p. 55, Pl. 1V, figs. 5—9.

Syn: Scolecithrix cristata, Giesbrecht.

“ Seaphocalanus acrocephalus, G. O. Sars.

Specific Characters.— Female. Body moderately slender, with the anterior
division pronouncedly navicular in form, being gradually attenuated anteriorly;
combined cephalosome and 1st pedigerous segment occupying fully half the length
of the entire body. Frontal part, seen lateraily, narrowly rounded and surmounted
by a very distinct, helmet-shaped crest. Lateral parts of last segment of meta-
some slightly angular below. Urosome equalling in length about '/; of the anterior
division, genital segment scarcely longer than the succeeding one. Caudal rami
very short, about as long as they are broad, apical setze much elongated, especially
the innermost but one. Eye apparently very small. Anterior antenne, when
reflexed, reaching about to the end of the anterior division. Anterior maxillipeds
with the pedicellated terminal appendages comparatively small. Last pair of legs
imperfectly 3-articulate, middle joint very small and not distinctly defined from
the terminal one.

Male rather more slender in form than female, frontal part somewhat
abruptly contracted, but without any trace of a crest. Last segment of metasome

with the lateral parts rounded off. Urosome considerably longer than in female,

Boe

exceeding half the length of the anterior division, genital segment very short,
2nd segment large and tumid, 5th segment very small; caudal rami mobile and
generally spread out. Anterior antenne with well-marked, band-like, sensory
appendages on the proximal part, 8th joint about the length of the 4 preceding
ones, and composed of several coalesced articulations, outer half of the antenne
very slender. Last pair of legs, when reflexed, scarcely reaching beyond the
middle of the urosome; both legs of about the same length, rami of the left one
nearly as long as the 2nd basal joint, and slightly incurved.

Colour not yet ascertained.

Length of adult female about 5 mm., of male 4'/. mm.

Remarks.—This form was first described by Th. Scott from a solitary,
somewhat defective female specimen, found in a plankton-sample taken off the Sao
Thomé Islands in the Gulf of Guinea. Apparently the same species was recorded the
following year by Dr. Giesbrecht from the Pacific, under the name of Scolecithrix
cristata. Neither of these statements had come under my notice when I was
examining the plankton-material from Nansen’s Polar Expedition. Indeed, I could
not, at that time, have imagined, that any of the polar forms were to be sought
for among species collected in the tropical parts of the ocean. Recent investiga-
tions have, however, proved that pelagic organisms may occasionally be carried far
from their true home by submarine currents; and therefore a thorough acquaintance
with those from other tracts of the oceans is indispensable in the determination
of such organisms. 1 cannot, indeed, find any essential difference between the
northern form and those observed by Th. Scott and Dr. Giesbrecht; and I am
therefore inclined to believe that all these 3 forms belong to one and the same
species, in spite of their widely remote occurrence.

The present species may be easily recognised, at any rate in the female
sex, by the peculiar, helmet-shaped crest on the frontal part. The caudal sete are
very brittle, and it is rather unusual to meet with a specimen having them all
uninjured. In the specimen examined by Th. Scott they were all broken at the base,
ad in the greater number of specimens collected during Nansen’s Polar Expedition,
they were also more or less defective. It is owing to this circumstance that
they have not been correctly figured in my account of that Expedition. I have
subsequently convinced myself that, as in other Scolecithricide, only 4 such sete
in reality occur on each caudal ramus, the 5th (outermost one) only being present
in quite a rudimentary condition, as a minute hair. The extremely delicate
terminal appendages of the anterior maxillipeds are also easily damaged, and their

peculiar structure was not clearly seen in the polar specimens at first examined.

53

Occurrence.—This handsome Calanoid, which is undoubtedly of true arctic
origin, has recently been stated by Mr. O. Nordgaard to occur off the Norwegian
coast, he having found some specimens, together with other relict arctic forms, in
the Herlé Fjord near Bergen, ‘at a depth of about 400 metres. I have myself found
it occasionally in 2 different plankton-samples taken during the cruise of the “Mi-
chael Sars” in 1900, the one from Stat. 9, located at some distance north of the
Shetland Islands, the other from Stat. 34, east of Jan Mayen, the depth being
recorded to be from 200 to 1000 metres.

Distribution.—Gulf of Guinea (Scott), Pacific in 35° N. Lat., 125° W.
Long. (Giesbrecht), Polar basin crossed by Nansen, in many places rather abundant

up to the very surface of the sea.

22. Amallophora brevicornis, G. O. Sars.
(Pl. XXXVI).

Scolecithrix brevicornis, G. O. Sars. The Norwegian North Polar Expedition,
Crustacea, p. 46, Pl. X.

Specific Characters.— Female. Body rather shorter and more robust in
form than in the preceding species, being less attenuated anteriorly, frontal part
obtusely rounded, and without any trace of a crest. Last segment of metasome
with the lateral parts angularly produced. Urosome comparatively slender,
somewhat exceeding '/; of the length of the anterior division. Caudal rami about
twice as long as they are broad, apical sete less elongated than in A. magna.
Anterior antennz comparatively short, not nearly attaining the length of the
anterior division, but otherwise agreeing in structure with those in A. magna.
Posterior antenne likewise of a very similar appearance. Pedicellated sensory
appendages of anterior maxillipeds comparatively larger, and curved in different
directions. Natatory legs very powerfully developed, and of almost exactly the
same structure as in A. magna. Last pair of legs likewise rather similar, though
comparatively smaller, and each only composed of 2 joints.

Male unknown.

Colour not yet ascertained.

Length of adult female not quite 2 mm.

Remarks.—This form, first described by the present author from Nansen’s
Polar Expedition, was at that time erroneously referred to the genus Scolecithrix
of Brady. On a closer examination, I have now convinced myself that it
ought really to be included in the genus Amallophora of Scott, as the terminal

appendages of the anterior maxillipeds exhibit the peculiar structure charac-

54

teristic of that genus, and as also a great similarity in the structure of the various
other limbs is found to exist between this and the preceding species. This form,
however, exhibits a rather different external appearance owing to the less pro-
nounced navicular form of the anterior division of the body, the complete absence
of any frontal crest, and the shortness of the anterior antenne. It is also of
far inferior size.

Occurrence.—A solitary, but well preserved, female specimen (the one here
figured) of this arctic form was found in a plankton-sample taken during the cruise
of the “Michael Sars” in 1900, at Stat. 34. As this Station is located within the
limits of the Norwegian Sea, the present Calanoid may properly be included in
the fauna of Norway.

Distribution.—Polar basin crossed by Nansen, in one place, north of
81° of latitude.

Gen. 14. Seolecithricella, G. O. Sars, n.

Syn: Scolecithrix, auctorum (part).

Generic Characters.—Body not very dissimilar in the two sexes, and of
comparatively short and robust form, with the anterior division more or less
strongly vaulted above, and very smooth, without any crest in front. Rostral
prominence bifurcate, each half tipped with a short, soft lappet. Last segment of
metasome united with the preceding one, and having the lateral parts rounded
off. Urosome comparatively small, especially in female. Caudal setee not much
elongated, and subequal. Anterior antenne in female rather slender, 22-articulate,
the last 2 joints being confluent, in male transformed in the usual manner.
Posterior antennz with the outer ramus longer than the inner. Mandibles with
the masticatory part but slightly expanded, inner ramus of palp well developed,
though smaller than the outer. Mavxille and posterior maxillipeds about as in
Amallophora. Anterior maxillipeds, however, with all the terminal appendages of
the same appearance, vermiform. Oral parts in male slightly transformed. Natatory
legs remarkably elongated, resembling in structure those in Amallophora; terminal
spine of outer ramus, however, not serrate, but very minutely denticulated outside.
Last pair of legs present in both sexes, in female very small, uniarticulate, lamellar,
with 2 comparatively short spines inside the tip; in male considerably produced,
right leg the longer and carrying at the end of the 2nd joint a styliform appen-
dage, left leg simple, with the 1st joint conspicuously dilated distally.

55

Remarks.—I have felt justified in establishing this new genus to include a
number of species previously referred to the genus Scolecithrix of Brady, but, like
Amallophora, differing materially from the type of this genus, 8. dane (Lubbock),
in the presence in the female of a 5th pair of distinct, though small legs. This
genus differs from Amallophora in the structure of these legs in both sexes, as
also in the uniform appearance of the terminal appendages of the anterior maxilli-
peds, these being all vermiform as in Scolecithrix. The type of this genus is
S. mimor of Brady, a species which seems to have a very wide distribution, and
also belongs to the Norwegian fauna. In addition to this, the following Mediter-
ranean species, recorded by Dr. Giesbrecht, are in all probability referable to
the same genus, viz. S. vittata, tenuiserrata, profunda, longipes, abyssalis, dubia,
dentata, marginata, longifurca. In the Northern Ocean, only the type species is
represented.

23. Seolecithricella minor (Brady).
(Pl. XXXVI & XXXVIID).
Scolecithrix minor, Brady, Report on the Copepoda of the Challenger Expedition,
p. 58, Pl. XVI, figs. 15, 16; Pl. XVI, figs. 1—5.

~.

Specific Characters—fKemale. Anterior division of body, seen dorsally,
oblong oval in form, greatest width but slightly exceeding '/; of the length, anterior
extremity narrowly rounded, posterior somewhat contracted; seen laterally, gently
vaulted above and obtusely truncated anteriorly, the dorsal margin forming
a remarkably bold curvature in front. Last segment of metasome with the
lateral parts somewhat lamellar, forming an obtuse corner below. Urosome unusu-
ally small and narrow, only slightly exceeding '/, of the length of the anterior
division, genital segment constricted at the base and not at all protuberant below.
Caudal rami comparatively short and somewhat divergent, with all the apical setz of
the same length. Eye very small, subventral. Anterior antenne moderately slender,
reaching, when reflexed, about to the end of the anterior division of the body,
the first 2 articulations not distinctly defined. 2nd and 3rd pairs of natatory
legs with scattered spinules on the hind face of both rami; 4th pair without such
spinules. Last pair of legs forming each a broadly oval lamella armed inside
the tip with 2 unequal spines, the distal one very small, the proximal one about
half the length of the lamella, outer edge with a small ledge at about the middle.

Male resembling the female both in size and general form, though having
the urosome more elongated and, as usual, 5-articulate, last segment very short.
Caudal rami comparatively shorter than in female and mobile. Anterior antennz

with well-marked, band-like, sensory appendages on the proximal part, and angularly

56

curved in the middle, number of articulations considerably reduced. Last pair of
legs very slender, reaching beyond the tip of the urosome, terminal joint of right
leg bayonet-shaped, that of left leg transformed to a thin oblong lamella.

Colour. Body in both sexes highly pellucid, and almost without any
pigment; natatory legs, however, generally tinged with yellow.

Length of adult female 1.40 mm., of male about the same.

Remarks.—I have been in some doubt about the identification of this
form, chiefly because Prof. Brady describes the 5th pair of legs in the female as
3-articulate. I think, however, that this must be due to a mistake, and that in
all probability the legs figured do not belong to a female specimen, but more
properly to an immature male. Otherwise the figures given agree pretty well
with the present form, the peculiar bayonet-shaped appearance of the terminal
joint of the right last leg in the adult male being exactly alike in the 2 forms.

Occurrence.—I lave met with this form occasionally along the greater
part of the Norwegian coast, from the Christiania Fjord northwards at least to
the Lofoten Islands. It has also recently been found, though rather sparingly,
in some of the plankton-samples taken in the open sea during the cruise of the
“Michael Sars” in 1900. In its habits this Calanoid is a true pelagic form, often
occurring close to the surface of the sea.

Distribution.—North Atlantic Ocean (Brady), Gulf of Guinea (Scott),
Indian Ocean (Giesbrecht).

Section 2.

Isokerandria.

This new section is established to comprise a number of Calanoids
which are distinguished from those belonging to the 2 sections recorded by Dr.
Giesbrecht (Amphascandria and Heterarthrandria) by the fact, that the anterior
antenne do not exhibit any conspicuous difference in the two sexes, and that the
oral parts, as a rule, are also of much the same appearance in the male and the
female. The hitherto known forms belonging to this section had previously been
referred partly to the Scolecithricide, partly to the Pseudocalanide, and partly to

Sl

the Misophruide. I think, however, that at any rate some of these forms ought to
be regarded as types of particular families. 4 such families are here established,
each as yet containing only a very limited number of genera. It is however very
probable that the number of genera will be considerably increased in the future;
for, owing to the peculiar habits of these Calanoids, our knowledge of the existing
forms is certainly still very imperfect. They all agree in being pronounced bottom-
forms, and cannot of course be captured in the ordinary tow-net, but only by the
aid of the dredge or by some other implements with which the very bottom is
swept. As they are of a very small size, moreover, it will be easily understood,
that they may to a great extent have escaped the attention of Carcinologists.
Indeed, our knowledge regarding these peculiar Calanoids we owe almost exclusively
to Th. Scott, who has succeeded in discovering many interesting deep-water Copepods
by subjecting the trawl-refuse of fishermen to a minute microscopical examination.
From other countries, we only know one solitary form referable to this section, viz.
the peculiar Calanoid first described by Dr. Giesbrecht as Moebianus gyrans, a
form which was only observed in the aquaria of the Zoological Station in Naples,
having probably been transferred to them quite accidentally with the various
bottom-organisms (Hydroids or Corals) growing in them. I myself, by the aid
of a very lhght dredge, long ago procured several forms belonging to this sect.on
at different parts of the Norwegian coast. These will be described below. On the
other hand, 1 have not felt justified in including in the Norwegian fauna any of
the additional species observed off the Scottish coast, by Th. Scott, on account of

the non-pelagic character of those Calanoids.

Fam. 9. Diaixide.

Characters.—General habitus recalling that in the Scolecithricide. Ce-
phalosome united with the 1st pedigerous segment, front produced below to an
undivided rostrum. Last segment of metasome distinctly defined from the pre-
ceding one. Urosome comparatively small, in female composed of 4, in male of
5 segments; caudal rami short, each with 4 subequal apical sete. Eye distinct,
double. Anterior antenne scarcely differing in the two sexes, comparatively
slender, with the last 2 articulations well defined. Posterior antennze with the
inner ramus unusually small. Oral parts on the whole resembling in structure
those in the Scolecithricide, the terminal appendages of the anterior maxillipeds

9 — Crustacea.

58

having a similar vermiform shape. Natatory legs with the same number of joints
in the rami as in that family. Last pair of legs wholly absent in female, in
male of extraordinary size and very complicated structure.

Remarks.—This family bears a close resemblance in several points to the
Scolecithricide, yet differing very materially, both in the uniform appearance of
the anterior antennz in the two sexes, and in the enormous development and
peculiar structure of the last pair of legs in the male. It contains as yet but a
single genus, to be described below.

Gen. 15. Diaixis'), G. O. Sars, n.

Syn: Scolecithrix, Scott (part).

Generic Characters—Body not very slender, with the anterior division
much vaulted in front. Rostral prominence simple, deflexed, without any tentacular
filaments. Last segment of metasome in female with the lateral parts lamellarly
produced. Urosome comparatively short, genital segment in female produced
dorsally. Eyes subventral, placed close together, though well defined in the middle.
Anterior antenne 24-articulate, with some of the sete of the terminal joints
ciliated. Posterior antennz with the outer ramus very large, 6-articulate, last
joint much the longest. Mandibles slender, with the masticatory part scarcely at
all expanded, inner ramus of palp poorly developed. Anterior maxillipeds with
the terminal appendages very delicate and all of the same appearance. Posterior
maxillipeds with the terminal part unusually short and reflexed. Natatory legs
slender, without any spinules on the hind face, terminal spine of outer ramus in
the 2nd to 4th pairs coarsely denticulate outside. Last pair of legs in male
transformed to a powerful graspmg organ, attached to the body by a thin and
flexible stalk, and composed of a large and tumid basal part and 2 rami of nearly
equal length, the right one forming the immediate continuation of the basal part,
the left one beig movably articulated to its posterior face.

Remarks.—This genus is established to include the peculiar form described
by Mr. A. Scott as Scolecithrix hibernica, which species most certainly does not
belong to Brady’s genus. In addition to the typical form, another nearly-allied
species has been recorded by Th. Scott as Scolecithrix pygmea. Only the first
of these species belongs to the fauna of Norway.

1) Nomen proprium.

59

24. Diaixis hibernica (A. Scott).
(Pl. XXXIX & XL).

Scolecithrix hibernica, Andr. Scott, Ann. Nat. Hist., 6th series, Vol. 18,
p-. 362, Pl. XVIT & XVIII.

Specific Characters —Female. Anterior division of body, seen dorsally,
elliptical in form, greatest width not attaining half the length, anterior extremity
narrowly rounded, posterior considerably contracted; seen laterally evenly vaulted
above and somewhat widening anteriorly, dorsal margin curving abruptly in front,
rostral prominence conical in form and extended straight downwards. Last seg-
ment of metasome very short and deeply emarginated in the middle, lateral pro-
jections irregularly triangular, and defined above by a slight incision of the margin,
being closely applied to the genital segment, to the end of which they extend.
Urosome not attaining even '/; of the length of the anterior division, genital
segment with a very conspicuous gibbous prominence dorsally. Caudal rami
somewhat longer than they are broad, and slightly dilated distally, each with a
small dentiform projection outside the apical sete, the latter but very slightly
divergent and somewhat exceeding the urosome in length. Anterior antenne,
when reflexed, reaching about to the end of the genital segment. Posterior
antenne with the outer ramus more than twice the length of the inner. Anterior
maxillipeds with about 5 vermiform appendages at the tip. Posterior maxillipeds
with the terminal part scarcely exceeding '/; of the length of the 2nd basal joint.
Natatory legs successively increasing in length posteriorly, 4th pair very slender,
with the terminal joint of outer ramus almost linear in form, and having the
proximal spine of the outer edge placed beyond the middle.

Male on the whole resembling the female in the general shape of the
body, but having the last\segment of metasome very small and not produced laterally.
Urosome more slender, and as usual 5-articulate, last segment very short. Last pair
of legs, when reflexed, reaching far beyond the tips of the caudal sete, basal part
with a comb-like series of about 5 curved spines on the left side; right ramus
somewhat band-like, irregularly flexuous and carrying on the tip a movable hand-
like piece produced into 2 digitiform processes, left ramus 4-articulate, with the
2nd joint the largest and produced outside into several irregular projections, last
2 joints comparatively short and somewhat lamellar, the terminal one carrying
inside a slender flexuous seta and 2 short spines.

Colour. Body in both sexes pellucid, with a faint carneous tinge, and
partly mottled with a pale rose pigment.

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

60

Remarks.—This form was first described in the year 1896 by Mr. Andrew
Scott, the son of the well-known Scottish naturalist, Thomas Scott, from speci-
mens procured in the Irish Channel by the aid of a small tow-net fastened to
the beam of a fish-trawl. I had myself long before observed this form in the upper
part of the Christiania Fjord, and had assigned to it the provisional name Diaixis
oleacea, owing to a peculiarity to be mentioned farther on. This form, though
resembling in its external appearance some species of the genus Scolecithricella,
may on a closer inspection be easily recognized in both sexes, the female by the
peculiar adpressed lateral projections of the last segment of the metasome, the
male by its enormously developed legs of last pair.

Oceurrence.—In addition to the Christiania Fjord, where it is rather com-
mon, I have met with this form occasionally in several other places of the Norwegian
coast, as far as up to the Trondhjem Fjord. It is found in moderate depths,
ranging from 20 to 60 fathoms, on a muddy bottom, and always close to the
ground. For capturing this and other delicate bottom-organisms, I have employed
a very light dredge, by which only a small portion of the superficial bottom-
material is taken up. If this material be placed together with a small amount of
sea-water in a shallow vessel, the specimens will at once make their appearance,
owing to a peculiarity which they have in common with some other micro-organisms,
namely, that when coming in contact with the surface, they invariably remain on it,
floating about like small air-bubbles, and they can thus easily be picked up by the
aid of a small feather.

Distribution.—Irish Channel (A. Scott), Scottish coast: Firth of Clyde,
Moray Firth, off Fair Islands (Th. Scott).

Fam. 10. Stephide.

Characters.—Form of body generally short and stout, not very dissimilar
in the two sexes. Cephalosome united with the 1st pedigerous segment, front
simple, without any rostral prominence or tentacular appendages. Last 2 seg-
ments of metasome coalesced. Urosome in female composed of 4, in male of 5
segments. Kye wholly absent. Anterior antenne of exactly the same appearance
in the two sexes, and rather slender, with the last 2 joints distinctly defined.

Posterior antennz and oral parts normal, the latter not transformed in male.

ot

Terminal appendages of anterior maxillipeds not sensory. Natatory legs with the
same number of joints in the rami as in the Diaixide, but not nearly so elongated.
Last pair of legs present in both sexes, in female rather small and of simple
structure, in male largely developed, uniramous, left leg the largest and having
some of the joints conspicuously dilated.

Rtemarks.—The type of this family is the genus Stephos of Scott (— Moe-
bianus, Giesbr.), which was placed by Dr. Giesbrecht within his subfamily Clazso-
calanine, answering to the family Psewdocalanide of the present account. I think,
however, that this arrangement is quite inadmissible, since this genus differs in
several points very essentially from the other genera of this family. The uniform
structure of the anterior antenne and the oral parts in both sexes proves it in
reality to belong to the section Jsokerandria, as here defined. The present family
likewise differs rather materially from the Diaizxide in the structure of the anterior
maxillipeds, as also in the presence of distinctly developed, though small, legs of
the 5th pair in the female, and the structure of these legs in the male. In addi-
tion to the typical genus, Stephos Scott, another apparently nearly-allied genus,

Parastephos, will be described below.

Gen. 16. Stephos'), Scott, 1892.

Syn: Moebianus, Giesbrecht.

Generic Characters.—Body of a rather short and compact form, with the
anterior division more or less tumefied. Front cut off, as it were, below, and not
forming any perceptible prominence. Lateral parts of last segment of metasome
rounded off, sometimes lamellarly expanded. Urosome comparatively short; caudal
rami likewise short, but with the apical sete rather elongated. Anterior antenne
moderately slender, 24-articulate, with scattered bristles in front. Posterior
antenne with the outer ramus longer than the inner. Anterior lip remarkably
prominent. Mandibles strong, with the masticatory part somewhat expanded,
outermost denticle not very different from the others; palp with the inner ramus
fully as large as the outer. Anterior maxillipeds comparatively small; posterior
ones well developed, with the terminal part elongated and not reflexed. Natatory
legs with the rami normal in both sexes. Last pair of legs in female 3-articulate,

1) I do not consider it necessary to change this name to Sfephus, as proposed by Dr.

Giesbrecht, since there are several generic names generally admitted in Zoology, which have
a similar Greek termination (Rhinoceros, Aceros, etc.)

62

with the last joint spiniformly produced; those in male very large, both legs well
defined and angularly curved near the base, the right one 4-articulate, terminating
ist a more or less claw-like piece, left 5-articulate, with the penultimate joint
much tumefied, last joint incurved and provided with a number of delicate leaf-like
appendages.

Remarks.—As above stated, this genus was first (in the year 1892)
established by Th. Scott, to include a small Calanoid found by him off the Scot-
tish coast, S. minor. In the same year, but somewhat later, Dr. Giesbrecht
described a Mediterranean form, undoubtedly belonging to the same genus, under
the name of Moebianus gyrans. and a 3rd species was subsequently recorded by
Th. Scott as S. Fultont. I have myself observed 2 additional species off the
Norwegian coast, to be described below. The genus accordingly comprises at
present 4 different species. In all these species the last pair of legs in both
sexes are built upon the very same type, though those of the male, at any rate,

exhibit characteristic differences in each species.

25. Stephos lamellatus, G. O. Sars, n. sp.
(Pl. XLI & XLII).

Specific Characters.—Female. Body very short and robust, more so than
in any of the other species, with the anterior division, seen dorsally, broadly oval
in form, greatest width exceeding half the length, anterior extremity narrowly
rounded, posterior slightly contracted and somewhat irregular; seen laterally,
moderately vaulted above, dorsal margin forming, in front, a perfectly even curve.
Last segment of metasome deeply emarginated in the middle, lateral parts lamellarly
expanded and conspicuously asymmetrical, right lamella much larger and broader
than left. Urosome very short, scarcely attaining '/; of the length of the anterior
division, genital segment asymmetrical, exhibiting on right side a rounded lamellar
prominence, but without any spiniform processes. Caudal rami scarcely longer
than they are broad, apical sets exceeding in length the urosome. Anterior
antenne rather slender, reaching, when reflexed, to the base of the caudal rami.
Posterior antenne with the outer ramus only slightly Jonger than the inner. Last
pair of legs with the terminal joint nearly straight, carrying outside, at some
distance from the base, a small spinule, distal part spiniform and very finely
ciliated outside.

Male resembling the female both in size and general form of body, but
having the lateral parts of the last segment of metasome symmetrical and not

Jamellarly expanded. Urosome somewhat narrower, and, as usual, composed of

63

5 segments besides the caudal rami. Last pair of legs very massive, both legs
of about equal length, but very dissimilar in form, penultimate joint of right leg
rather elongated and somewhat lamellar in form, gradually tapering distally,
terminal joint of same leg rather irregular in shape, with several obtuse, digiti-
form processes; penultimate joint of left leg very large and tumid, with a strong
spiniform process inside at the base, and a row of delicate spinules along the
inner face, terminal joint carrying at the tip a dense fascicle of lanceolate, leaf-
like appendages.

Colour. Body in both sexes very pellucid and ornamented with a beautiful
rosy pigment.

Length of adult female somewhat exceeding 1 mm., of male about
the same.

Remarks.—This form may easily be recognized from any of the other
species by its unusually short and robust form, as also by the lamellarly expanded
lateral parts of the last segment of the metasome in the female, and the structure
of the last pair of legs in both sexes. It is also of a larger size than any of
the other known species.

Occurrence.—I have met with this form not unfrequently at Bodé and
Hammerfest, Finmark, in depths of about 30 fathoms, muddy bottom. I have also
come across it, though only occasionally, off the west coast of Norway (Chri-
stiansund).

26. Stephos Scotti, G. O. Sars, n. sp.
(Pl. XLII.

Syn: Stephos gyrans, Scott (not Giesbrecht).

Specific Characters —Female. Body comparatively less robust than in the
preceding species, with the anterior division, seen dorsally, regularly elliptical in
form, greatest width scarcely exceeding half the length, both extremities almost
equally tapered; seen laterally, considerably vaulted above, with the dorsal margin
strongly curved in front. Lateral parts of last segment of metasome perfectly
symmetrical, not lamellarly expanded. Urosome exceeding in length 1/3; of the
anterior division, genital segment symmetrical, without any prominences or pro-
cesses. Caudal rami somewhat longer than they are broad, apical set rather
slender. Anterior antennsze, when reflexed, reaching about to the end of the 2nd
caudal segment; posterior antenne with the outer ramus almost twice as long as
the inner. Last pair of legs with the terminal joint slightly flexuous, without
any spinule at the base, but armed outside the distal part with about 10 coarse
denticles.

64

Male somewhat smaller than female, and having the urosome considerably
more slender. Last pair of legs very large, with the right leg somewhat longer
and much more slender than left, its penultimate joint rather narrow and produced
at the base outside to an acute lappet, terminal joint forming a strong curved
claw, with a thumb-like projection at the base inside; penultimate joint of left
leg much tumefied, but quite simple, without any processes or spinules, terminal
joint carrying a row of 4 rather small leaf-hke appendages outside, and at the
tip 2 short, juxtaposed claw-like lamelle.

Colour. Body in both sexes extremely pellucid, with a very faint
yellowish tinge.

Length of adult female 0.95 mm., of male 0.85 mm.

Remarks.—This species is easily distinguished from the preceding one by
its more slender form, the perfect symmetry of both the last segment of the
metasome and of the genital segment, and finally by the structure of the last pair
of legs in both sexes. The form recorded by Th. Scott from the Scottish coast
as S. gyrans, Giesbrecht, is identical with the present species, as proved by the
examination of a specimen kindly sent to me by that author. The female of the
Mediterranean species differs very conspicuously in the asymmetrical shape of
both the last segment of the metasome and the genital segment, the latter being
moreover distinguished by a number of irregularly arranged spiniform processes
not found in any of the northern species. In the male of that species, too, the
last pair of legs, as figured by Dr. Giesbrecht, exhibit well marked differences from
those in the present species, which more resemble those in S. minor of Scott.

Occurrence.—I observed this form, many years ago, in a single locality
on the west coast of Norway, viz., Eggesbiénes, south of Aalesund. It occurred
here not unfrequently at a depth of a few fathoms, on a sandy bottom covered
with a thin layer of dark mud; and it was several times watched in the living
state. Its movements are rather curious, constituting a perfectly regular whirling
run, in which the body is kept in a horizontal attitude just above the bottom.
For this reason I assigned to it the provisional name of Typhlocalanus gyrator,
the generic name referring to the entire absence of visual organs. The same
peculiar manner of motion is also mentioned by Dr. Giesbrecht in the Mediter-
ranean species, and is most probably common to all the species of this genus.

Distribution.—Scottish coast: Loch Fyne, Firth of Forth (Scott.)

65

Gen. 17. Parastephos, G. O. Sars, n.

Generic Characters.—Form of body more slender than in Stephos, with
the anterior division less tumefied and the urosome more elongated. Front
blunt below, as in Sfephos. Antenne about as in that genus. Oral parts
likewise of a very similar structure, except that the masticatory part of the
mandibles is considerably more expanded, with the outermost cutting-tooth very
large and claw-like. Natatory legs not particularly powerful, some of them (in
male) peculiarly transformed. Last pair of legs in male largely developed and
very asymmetrical, right leg slender and terminating in a strong denticulated
claw, left leg much coarser, with the antepenultimate joint the largest.

Remarks.— This new genus is founded upon a solitary male specimen,
which, though evidently referable to the present family, exhibits so many essential
differences from the males of the genus Stephos, that it cannot properly be included
in that genus. It is very probable, that also the female, when found, will exhibit

some peculiarities, at least in the structure of the last pair of legs.

27. Parastephos pallidus, G. O. Sars, n. sp.
(Pl. XLIV).

Specific Characters.—Male. Anterior division of body, seen dorsally,
oblong oval in form, greatest width not attaining half the length, anterior extremity
narrowly rounded, posterior less attenuated; seen laterally, moderately vaulted
above, with the dorsal margin forming a perfectly even curve as far as the blunt
rostral part. Last segment of metasome with the lateral parts but slightly pro-
duced and narrowly rounded at the tip. Urosome comparatively slender, con-
siderably exceeding half the length of the anterior division, last segment well
developed. Caudal rami somewhat longer than they are broad, and not at all
divergent; apical sete about as in Stephos. Eye, as in that genus, wholly absent.
Anterior antenne, when reflexed, reaching about to the end of the 3rd caudal
segment, structure exactly as in Stephos. Posterior antenne with the outer ramus
considerably longer than the inner. Outer ramus of right 2nd leg peculiarly trans-
formed, being quite short, not even attaining the length of the inner ramus, and
composed of only 2 joints, the proximal one simple, the distal one carrying at
the tip 4 natatory sete and a single spine outside them. Inner ramus of right,

4th leg much larger than that of the left, middle joint considerably dilated,

10 — Crustacea.

66
terminal one armed on the hind face with 2 very coarse spinules, and having
moreover the proximal seta of the inner edge transformed into a slender spine,
denticulated inside. Last pair of legs, when reflexed, reaching to the end of the
caudal rami, distal part of right leg very narrow and (in the specimen examined)
doubled back upon the proximal part, terminal claw very strong and somewhat
flexuous, with a regular row of denticles along the concave edge; left leg with
the antepenultimate joint much dilated, and projecting at the end outside into
an oval lamella, terminal joint spoon-shaped.

Colour. Body highly pellucid, with a very faint yellowish tinge.

Length of adult male 1.90 mm.

Remarks. As stated above, this form is as yet only known in the
male sex. The female will in all probability be less slender in form, with the
urosome shorter and 4-articulate. Whether the last pair of legs of the female
is constructed after the type of the species of Stephos, cannot be conjectured
at present.

Occurrence.—The solitary specimen described above was found, many
years ago, at Sjerjehavn, west coast of Norway, in a depth of about 100 fathoms,
soft, muddy bottom.

Fam. 11. Tharybide.

Characters.—Form of body short and stout. Cephalosome united with
the Ist pedigerous segment, front carrying below 2 soft tentacular appendages.
Last 2 segments of metasome coalesced. Urosome short, in female 3-articulate,
in male 4-articulate, the last segment being obsolete. Eye present. Anterior
antenn slender and of exactly the same appearance in the two sexes. Posterior
antennze with the outer ramus much larger than the inner. Oral parts of same
appearance in the two sexes, and rather differing in structure from those in the
2 preceding families; terminal appendages of anterior maxillipeds very delicate,
sensory. Natatory legs with the same number of joints in the rami as in the 2
preceding families. Last pair of legs present in both sexes, in female of com-
paratively simple structure, in male very large, though rather slender in form,
with none of the joints conspicuously dilated.

67

Remarks.—This new family at present comprises only a single genus,
which, however, cannot properly be placed in any of the other families here
recorded. In some features, and more especially in the structure of the anterior
maxillipeds, it exhibits some resemblance to the Phaénnide; but the uniform
appearance of both the anterior antenne and the oral parts in the two sexes
proves it in reality not to belong even to the same section, but evidently to the

one here in question, viz., the Lsokerandria.

Gen. 18. Tharybis’), G. O. Sars, n.

Generic Characters. Body unusually short, with the anterior division
considerably tumefied. Front without any rostral prominence. Urosome rather
short in female, considerably more slender in male. Caudal rami short, each with
3 apical sete. Eye of a somewhat unusual appearance, being very large and
placed close to the dorsal face. Anterior antennz 24-articulate, with scattered
bristles in front, last 2 articulations well defined. Posterior antenne with the
Inner ramus rather small. Mandibles strong, with the masticatory part very com-
pact, cutting edge exhibiting outside 2 unusually strong bifid teeth followed by a
dense series of partly ciliated setz, palp with both rami well developed. Maxillee
or a somewhat unusual appearance, the masticatory lobe being exceedingly large,
with strong spines inside, whereas the palp is comparatively poorly developed.
Anterior maxillipeds with the terminal appendages extremely delicate and penicillate
at the tip, as in the Phaénnide. Posterior maxillipeds not much elongated, 2nd
basal joint fusiform, terminal part comparatively short and not reflexed. Natatory
legs of moderate size, and without any spinules on the hind face. Last pair of
legs in female 3-articulate, terminal joint linear and strongly spinous at the tip;
in male very large and rather asymmetrical, left leg biramous, right simple.

Remarks.—Dr. Giesbrecht would probably have placed this genus within
his sub-family Scolecithricine, which also comprises the genera Xanthocalanus
and Phaénna; and indeed, in external appearance, and more especially in the
structure of the anterior maxillipeds, it strongly recalls the last-mentioned genus.
It is, however, im reality very different, being not only distinguished by the uni-
form appearance in the two sexes of both the anterior antenne and the oral parts,
but also by the presence in the female of distinctly developed legs of the 5th pair.
We know at present only a single species, to be described below,

1) Nomen proprium.

68

28. Tharybis macrophthalma, G. O. Sars, n. sp.
(Pl. XLV & XLVI).

Specific Characters.—Female. Anterior division of body, seen dorsally,
regularly elliptical in form, greatest width equalling about half the length, both
extremities almost equally attenuated; seen laterally, much vaulted above, with
the dorsal margin forming quite an even curve throughout. Front scarcely at all
produced below, tentacular filaments very delicate and reflexed. Lateral parts of
last segment of metasome but slightly produced, forming narrowly rounded lobes.
Urosome scarcely exceeding in length '/; of the anterior division, genital segment
about twice as large as the succeeding one, and slightly protuberant below. Caudal
rami a little longer than they are broad, apical sete of moderate length, the
innermost but one the longest. Eye very large and conspicuous in the living
animal, oblong quadrangular in form, and occurring close to the dorsal face, pig-
ment bright red. Anterior antenne, when reflexed, reaching about to the end of
the anterior division. Posterior antenne with the inner ramus scarcely half as
long as the outer, terminal joint of the latter much the largest. Last pair of legs
with the terminal joint more than twice the length of the other 2 combined, nearly
straight and of uniform width throughout, exhibiting outside in the middle a small
dentiform projection, tip armed with 3 short, thick, denticulated spines, the
innermost the largest and distinctly defined at the base, the other 2 confluent
with the joint.

Male somewhat smaller than female, and having the urosome considerably
more slender, equalling about half the length of the anterior division. Last pair
of legs, when reflexed, reaching far beyond the caudal rami, right leg doubly
geniculate, 3-articulate, 1st joint rather thick and forming outside an angular pro-
minence, 2nd joint slender, slightly widening distally, terminal joint constituting a
claw-like incurved piece; left leg with the 2 basal joints very movably connected,
outer ramus 3-articulate, terminating in a bunch of delicate hairs, inner ramus
uniarticulate, styliform, and nearly twice as long as the outer.

Colowr.—Body in both sexes highly pellucid, with translucent dark yellowish
brown intestine.

Length of adult female 1.40 mm., of male 1.30 mm.

Remarks.—This Calanoid may be easily recognized by its unusually short
and robust form, and in the living state, also by the large, dorsally placed, bright
red eye. The anterior antenne in the living animal are born in a somewhat
unusual manner, exhibiting at the base an abrupt curve, and pointing obliquely
backwards.

69

Occurrence.—I first found this peculiar Calanoid, many years ago, in the
Christiania Fjord at Drébak, where some few specimens were taken up in the
dredge from a depth of about 100 fathoms. Subsequently I have also met with
it occasionally off the west coast of Norway, and as far north as in the Trond-
hjem Fjord, where a solitary specimen was procured from a depth of about
150 fathoms.

Fam. 12. Pseudocyclopiide.

Characters.—Form of body unusually compact, recalling that in some of
the Cyclopoida. Cephalosome confluent with the Ist pedigerous segment; front
produced below to a distinet rostrum. Last 2 segments of metasome united.
Urosome in female distinctly 4-articulate, in male 5-articulate. Kye wholly absent.
Anterior antennz of exactly the same appearance in the two sexes, and remarkable
for their shortness and restricted number of articulations. Posterior antenne with
the basal part imperfectly defined from the inner ramus, which is much longer
than the outer. Oral parts on the whole normal, except the mandibles, the cutting
edge of which does not exhibit the regular dentition found in other Calanoids.
Natatory legs having the same number of joints in the rami as in the 3 preceding
families, being, however, distinguished by their unusually short and compact form,
somewhat recalling that in the Cyclopoida. Last pair of legs present in both
sexes, in female comparatively simple, in male rather complicated and very
asymmetrical.

Remarks.—This new family is established to include the genus Pseudo-
cyclopra of Scott, which, though eviden'ly belonging to the present section, cannot
properly be placed in any of the 3 preceding families. It is more especially the
unusual appearance of the 2 pairs of antennz, which distinguishes this genus, and
tends to remove it from the general Calanoid type. We are at present only
acquainted with this solitary genus; but it is very probable, that on a future,
closer examination of the small Calanoids living at the bottom of the sea, some

other nearly-related genera will be found to exist.

70

Gen. 19. Pseudocyelopia, Scott, 1892.

Generic Characters.— Body short and compact, with the anterior division
strongly vaulted above and more or less compressed. Rostral prominence deflexed,
without any tentacular appendages. Lateral parts of last segment of metasome
rounded off. Urosome with the last segment well developed in both sexes;
caudal rami short, each with 4 apical sete. Anterior antenne very unlike those
in other Calanoids, being unusually short and tapering rapidly distally, with 16
to 20 articulations, the 1st very large. Posterior antennze with the outer ramus
6-articulate and much shorter than the inner. Mandibles very strong, masticatory
part thickened and having the cutting edge irregularly curved and minutely denti-
culate, palp with both rami well developed. Maxille normal. Anterior maxillipeds
with the terminal appendages simple, setiform. Posterior maxillipeds slender,
with the 1st basal jot remarka ly produced at the end anteriorly; terminal part
reflexed. Natatory legs with the spines of the outer ramus remarkably strong,
the terminal one in 2nd to 4th pairs coarsely serrate outside; seta of the Ist
basal joint in 3rd pair transformed to a strong elongated spine. Last pair of
legs in female 3-articulate, terminal joint the largest and spiniferous; those in
male of moderate size, both legs uniramous, the right terminating in a styliform
claw, the left with the basal part considerably tumefied, outer part slender,
triarticulate.

Remarks.—This genus, established by Th. Scott, was erroneously referred
by that author to the family Misophriide, which, as shown by Dr. Giesbrecht, does
not even belong to the Calanoida, but more properly to the Cyclopoida. The
generic name Lseudocyclopia, proposed by Th. Scott, bears an inconvenient
resemblance to Pseudocyclops, a genus which does not belong to this, but to the
next section (Heterarthrandria), though it certainly exhibits some resemblance in
its external appearance, to the genus in question. Th. Scott records no less
than 3 different species of this genus, viz., P. crassicornis, mimor and caudata,
all of them found in the Firth of Forth. None of these species have hitherto
come under my notice. On the other hand, a form observed by me many years
ago off the west coast of Norway, has proved to be identical with a 4th species
recently described by Mr. Thompson from Liverpool Bay. ‘This species will be
described below. |

cal

29. Pseudocyclopia stephoides, Thompson.
(Pl. XLVII & XLVIII).
Pseudocyclopia stephoides, J. C. Thompson. Proc. Liverp. Biol. Soc., Vol. 9, p. 96, Pl. 6,
fies, 12. Plo7, figs, S—14-

Specific Characters.—Kemale. Anterior division of body, seen dorsally,
of nearly uniform width throughout, and oblong oval in form, anterior extremity
obtusely rounded, posterior scarcely at all contracted; seen laterally, considerably
vaulted above, dorsal margin forming in front a perfectly even curve as far as the
rostrum; the latter somewhat flattened and acutely triangular in form. Lateral
parts of last segment of metasome forming short rounded lobes. Urosome com-
paratively robust, about equalling in length '/; of the anterior division, and without
any dorsal] processes (present in P. minor), genital segment about the length of
the 2 succeeding segments combined. Caudal rami only slightly longer than they
are broad, and obliquely rounded at the tip, apical sete of moderate length.
Anterior antennse not attaining even half the length of the anterior division of
body, and composed of 20 articulations, the 1st of which is very large, though
not attaining half the length of the remaining part of the antenne. Posterior
antenne with the inner ramus remarkably produced, being about twice as long
as the outer. Last pair of legs with each of the first 2 joints exhibiting a small
dentiform projection inside, 2nd joint not conspicuously dilated, terminal one
produced at the tip to a slender, straight spine, and carrying outside, attached
to separate ledges, 2 similar, though somewhat smaller spines.

Male resembling the female both in size and general form, though having
the urosome, as usual, more slender. Last pair of legs very asymmetrical, right
leg exceedingly slender, with the terminal joint occupying more than half its length
and having the distal part straight and band-like; left leg with the basal part
tumefied to an extraordinary degree, penultimate one carrying outside, at some
distance from the base, a small seta, distal part slightly expanded and having
on each side an acute lappet, terminal joint small and somewhat spoon-shaped.

Colour. Body in both sexes pellucid, with a faint yellowish tinge.

Length of adult female 1.20 mm., of male about the same.

Remarks.—This is the largest of the 4 hitherto known species, and
moreover easily recognized by the 20-articulate anterior antenne, the greatly
produced inner ramus of the posterior ones, and the structure of the last pair of
legs in both sexes. In its external appearance it bears a very close resemblance
to P. crassicornis, Scott. which, however, has the anterior antenne still shorter
and composed of only 16 articulations.

72

Occurrence.—Some few specimens of this form were found, many years
ago, at Christiansund, west coast of Norway, in a depth of about 30 fathoms.
This is the only place on the Norwegian coast where I have as yet met with it.

Distribution.—Liverpool Bay (Thompson).

Section 3.

Heterarthrandria.

This section comprises the greater number of the hitherto known Calanoids,
and among them are some of the most highly organized forms. Whereas the 2
preceding sections only contain marine forms, the present one is represented both
in the sea and in inland-lakes and ditches; some forms being also found in more
or less brackish water. The name of the section refers to the very dissimilar
appearance of the 2 anterior antenne in the male, one of them being much of
same structure as in the female, whereas the other, as a rule the right one, is
peculiarly transformed, constituting a powerful grasping organ, by the aid of
which the female is seized during copulation. This prehensile antennz exhibits
beyond the middle a very movable articulation, which admits the terminal part to
be doubled back upon the adjoining part, the latter being, as a rule, greatly
tumefied and traversed by a strong muscle, which acts upon the terminal part.
Thereby the said antenna becomes, as it were, divided into 3 successive sections,
generally well defined from each other: a basal, a median, and a terminal one.
More rarely the geniculate character is less pronounced, for instance in the genus
Acartia; but in the far greater number of forms it is very conspicuous, so as
at once to make these Calanoids recognizable from those belonging to the 2 pre-
ceding sections. The 5th pair of legs are always present in both sexes, though
in the female they may be much reduced in size. In some cases these legs are
natatory, like the preceding pairs; but in the male the outer ramus is always
somewhat transformed, and at any rate in one of the legs, generally the rigth
one, pronouncedly prehensile in structure. No difference whatever is found in

the structure of the oral parts in the two sexes, and, on the whole, the general

Copepoda

Calanorda.

Phaennide

GitieSoecraatod :
AOSeuiat togr. Tryktiden private Opmaaling Chra

-Xanthocalanus_ propingvus. G.0.Sars

PL XXXIV

alanotda.

Copepoda
C

Scolecithricide

CS
SSS
So eT

i pe

<<
Ne

Tryktiden private Opmaaling Chra

G.0. Sars autogr.

Scott

magna,

Amallophora

Copepoda

Calkamorda:

“ Yo Wee Pa ‘ A
Lv Bogie
LE
Sg Oe oat
i a

fies -
%Ze Fe OPIATE OS

Tryktiden private Opmaaling, Chra.

/

zy} SID) ape ae Berean = a ss
Se Beh | eee Se =
S a <a es
: S eo :
\ :

~~
'

Scolecithricida

Scott

magna,

Amallophora

(continued)

Copepoda

KV]

Calanorda. Pl

Scolecithricida.

Spear an in
2 ae
= S2==
bet Se sone SOO —

Tryktiden private Opmaaling, Chra.

6.0. Sars autogr. -

Amallophora brevicornis, G.0.Sars.

PI. XXXVII

epoda

Pp
Calanorda.

Cie

Scolecithricida.

a

List

F ft ge

Trykt iden private Opmaaling, Chra

( Brady.)

minor

Scolecithricella

Dye I Poe

SS = ae

: <
Ss 5

7 pA ee Se nn

aS
eS

PL XXXVI

pepoda
Calanorda.

Co

Scolecithricida.

SS Ree
SS
ec
a5

Tryktiden private Opmaaling, Chra

6.0. Sars auto gr.

( Brady.)

minor

(continued)

Scolecithricella

1. XXXIX.

Ir

Copepoda
Calancrda

Diaixida.

s autogr.

Gus
oar

6.0

Tryktiden private Opmaaling,Chra

hibernica (Scott)

Diaixis

Calanoida. PE

Copepoda

Diaixida.

se eS Gor— = — a
————

Sa

Tryktiden private Opmaaling, Chra

hibernica (Scott)

(continued)

Diaixis

G.0. Sars autogr.

7 7 7
cay
: =
-
= =) * 3
ie - a
5 ays
ii
a,
- 7
a | il eS
= e
7
? Se)
=e
;
7
=
?
v
7 ~
EL
v
yy
> ae
®
Mt 7
7 e
.
Fe 2

cout
3, a ]

i " _
i oe :
me wy -
oa .
| |
~ : .
> oa
0. ty 2
= > .
os my
@ + -
® -
- Ah
= :
Ls

S)
)
oe
is |
i

ae.
> Somat

y

s «fr A

"

Ja

Copepoda

PL AL

ano(aa.

eal

Stephide

vktiden private Opmaaling Chra

Tr

7p)
ie
19.8]
Lop)
(=)
c
|
“4
=
=
ay
o
Ee
oS
a
fo)
oe on}
QW.
a
+
cf
L
wo
z ay)

Copepoda

Stephidar Calanorda Bea

ars autoar Trykt iden orivate Opmaaling Chra
Stephos lamellatus 6G. 0. Sars.

(continued )

6.0

PI. XLUL

2 OTe
ES Be eS
= —— Tarra ed ES

poda

alanotcma:

=
aN
“Sa,
mA
ENN
DON,
S

Cope
C

ED pe By:
LEE SES =

SRO

Stephida.

An ED meee
a rT ER a PA OP CR MRA PALE EOE iD BID A ANTRAL DY ERED RT ETE LE PELE IS STE BREST

|
|
|

aaling Chra

rprivare Oo

ars autoar

Sh

G.0

Catanordaa. PI. XLIV

Copepoda

Stephide

Teyxtiden private Opmaaling, Chra

Sars autoar

pallidus G. 0. Sars.

Parastephos

Se

poda
Calanorda.

Cope

Thary bide.

Tryktiden private Opmaaling, Chra

macrophthalma_ G. 0. Sars._

harydis

Tr

Tryktiden private Opmaaling, Chra

SE

<

pepoda
Calanoida.

Co

: i

3 6

=>
= | °
co, a
Pi = 0
=>} a
fn. ¥ Ks
4 top
a= )
aia ©

macrophthalma G. 0. Sars.

Tharybis

(continued).

Copepoda

PI. XIVIL

Calanorda

Pseudopcyclopiida.

Tryktiden private Opmaaling, Chra

GC. Sars autogr.

stephoides, Thomps

Pseudocyclopia

Copepoda

Pseudopcyclopida

Calanoraa

Tryktiden private Opmaating, Chra

G.0 Sars autogr.

stephoides , Thomps

(continued)

Pseudocyclopia

| a
eee
La Oe,
ig ia 5

a

i
mm.
E
st
'
@
=
‘
'
~*
au
ee te
==
oe

AS vr...
oe

AN ACCOUNT

OF THE

SRUSTACER

OF

NORWAY

WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

1BNG

G. O. SARS

VOL. IV

COPEPODA
CALANOIDA

PART VII & VIII
CENTROPAGIDA, DIAPTOMIDA.

WITH 16 AUTOGRAPHIC PLATES

BERGEN
PUBLISHED BY THE BERGEN MUSEUM
SOLD BY
ALB. CAMMERMEYER’S FORLAG, CHRISTIANIA
1902

_maa ) &

ie

Pa

73

habitus does not exhibit such great sexual dissimilarity as is often met with in the
Amphascandria. The males, moreover, occur in about the same number as the
females, whereas in the above-mentioned section, male specimens are, as a rule,
very rare, and apparently confined to certain seasons.

The subdivision of this section is connected with no small difficulty,
owing to the great variation in the structure of the several appendages. In his
great work, Dr. Giesbrecht only records 3 families belonging to this section, viz.,
the Centropagide, the Candacide and the Pontellide, the first being subdivided
into 4, and the last into 2 subfamilies. According to the plan followed in the
present account, these subfamilies are here raised to the rank of true families,
and their number has moreover been considerably increased. I think we must at any
rate admit the following 14 families: Centropagide, Diaptomide, Pseudodiaptomide,
Lucicutiide, Temoride, Metridude, Heterorhabdide, Arietellide, Candacude,
Pontellide, Parapontellide, Acartiide, Tortanide, Pseudocyclopide. With the
exception of the Psewdodiaptomide'), the Lucicutide*) and the Tortanide*), all
these families are represented in the fauna of Norway, and they will be mentioned

in the following pages, short diagnoses being given of each of them.

Fam. 13. Centropagide.

Characters.—Cephalosome well defined from the Ist pedigerous segment,
front with 2, generally soft appendages below. Last 2 segments of metasome
likewise; as a rule, well defined. Urosome consisting in female of 3, in male of
4 or 5 segments; caudal rami more or less elongated, with the full number of
sete. Anterior antenne consisting in female of 24 or 25 articulations; right
antenna in male distinctly geniculate. Posterior antenne and oral parts on the
whole normal. The 4 anterior pairs of legs with both rami 3-articulate. Last

pair of legs in female biramous, natatory, outer ramus with a strong unguiform

1) In this family, I propose to include the 2 genera Pseudodiaptomus, Herrick, and Poppella,
Richard, which are undoubtedly nearly related, and together form a natural group somewhat
intermediate between the Diaptomide and the Temoride.

*) This family, answering to the sub-family Leuckartiine of Giesbrecht, contains the following
3 genera: Lucicutia, Giesbr., Isocheta, Giesbr., and Disseta, Giesbr.

3) This family is established to include the 2 anomalous genera, Tortanus, Giesbr. (= Corynura
Brady) and Mormonilla, Giesbr.

11 — Crustacea,

74

projection issuing from imside the 2nd joint; those in male with the outer rami
more or less transformed and dissimilar, that of right leg, as a rule, the stronger.

Remarks.—In the restriction here adopted, this family is chiefly charac-
terised by the structure of the legs, the 4 anterior pairs having both rami
3-articulate, and the last pair, at any rate in the female, being natatory, like
the preceding pairs. ‘The strong unguiform projection always found inside the
outer ramus of the last pair of legs in the female is also very characteristic. The
family comprises as yet 5 genera, viz., Centropages, Kroyer, Isias, Boeck, Limno-
calanus, G. O. Sars, Osphranticum, Forbes, and Boeckella, Thomson. Of these
genera, the first 2 are exclusively marine, whereas the other 3 are chiefly peculiar
to fresh water. The first-named 3 genera are represented in the fauna of Nor-

way, and will be treated of below.

Gen. 20. Centropages, Kroyer, 1848.
Syn: Ichtyophorba, Tiitienens

Generic Characters.—Body moderately slender, with the cephalosome some-
what contracted in front, and having a well-marked cervical depression dorsally ;
rostral appendages in some cases transformed to rigid spikes. Last segment of
metasome distinctly defined from the preceding segment, and having the lateral
parts, as a rule, expanded and acutely produced. Urosome in female more or
less asymmetrical, in male generally composed of only 4 segments. Caudal rami
of moderate length, with the setse comparatively short. Eye well developed,
subyentral, and generally forming a distinct bulging below. Anterior antennz very
slender, consisting in female of 24 articulations, the last 2 joints being coalesced.
Posterior antenne with the outer ramus longer than the inner, and 6-articulate.
Anterior maxillipeds with the distal setee remarkably elongated, almost claw-like.
Terminal joint of outer ramus in the 3 middle pairs of legs with 3 spines outside.
Last pair of legs with the inner ramus well developed in both sexes and 3-arti-
culate; outer ramus of left leg in male biarticulate, that of right leg 3-articulate,
the last 2 joints forming together a powerful chela. No ovisac present in female.

Remarks.—This genus was established as early as the year 1848 by
Kréyer, to include 2 species found by him, the one in the Atlantic Ocean, the
other off the coast of Chili. As first shown by Boeck, the genus Ichtyophorba

(ess

of Lilljeborg is unquestionably identical with Kréyer’s genus. The chief distinguishing
character of this genus consists in the structure of the last pair of legs, the powerful
chela formed by the outer ramus of the right leg in the male being especially
very characteristic. We know at present about 13 species of this genus, occurring
in different parts of the Oceans. All these species are marine and pelagic in their
habits, sometimes occurring in great shoals close to the surface of the sea. Two of

the species belong to the fauna of Norway, and will be described below.

30. Centropages typicus, Kroyer. :
(Pl, XEN, 1, Til):
Centropages typicus, Kroyer. Nat. Tidsskr. New series, Vol. 2, p. 588, Pl. VI, figs. 22—26.

Syn: Ichtyophorba denticornis, Claus.

Specific Characters.— Female. Anterior division of body somewhat depressed,
‘seen dorsally, oblong oval in form, greatest width considerably exceeding 1/3; of
the length, anterior extremity conspicuously contracted, posterior scarcely at all
attenuated. Cephalosome less distinctly separated laterally from the Ist pedigerous
segment, front projecting below into 2 rigid, deflexed spikes. Last segment of
metasome with the lateral parts considerably expanded, and projecting at the
outer corner into a strong spiniform projection pointing obliquely backwards, and
somewhat more extant on right than on left side. Urosome conspicuously asym-
metrical, and generally turned more or less to left side, genital segment scarcely
longer, and but slightly broader, than the succeeding segment, and carrying near
the hind edge 4 somewhat irregularly arranged slender spines, 2 subventral and
2 subdorsal, the latter distinctly denticulate; middle segment with a slight knob-
like protuberance on the right side; last segment comparatively short. Caudal
rami about twice as long as they are broad, and slightly widening distally, being
somewhat divergent and finely ciliated inside; innermost but one of the apical
sete nearly twice as long as the others. Eye forming a very conspicuous bulging
below. Anterior antenne, when reflexed, reaching to about the tip of the caudal
rami, Ist, 2nd and 5th articulations each produced in front to a well-developed
dentiform projection. Outer ramus of last pair of legs with the unguiform pro-
jection of the middle joint very strong, equalling in length the terminal joint.
Male somewhat more slender than female, and having the lateral expan-
sions of last pedigerous segment less divergent, and conspicuously asymmetrical,
the left one being much larger than the right. Urosome perfectly symmetrical
and rather slender, composed of 4 segments only. Caudal rami somewhat longer

than in female, with the outermost seta quite short and spiniform, without cilia.

(6

Right anterior antenna with the middle section rather tumefied, its antepenultimate
joint having a strong denticle in the middle of the anterior edge. Chela of last
pair of legs very powerful, thumb strongly developed, of about the same length
as the dactylus, and unguiformly incurved at the tip.

Colour. Body in both sexes rather pellucid, in female being often tinged
with orange or light chestnut in the middle of the anterior division.

Length of adult female reaching 1.75 mm., of male 1.60 mm.

Remarks —This handsome species was first described by Kréyer under
the above name, and was subsequently recorded by Claus, who regarded it as
new, and described it as Ichtyophorba denticornis. It is easily recognizable from
the 2nd Norwegian species by the strong rostral spikes, the form of the lateral
expansions of the last pedigerous segment, and that of the urosome in the female,
and finally, by the conspicuous dentiform projections on the anterior antenne,
and the very powerful chela of the right last leg in the male.

Occurrence.—This form is found along the whole southern and western
coast of Norway, at least up to the Trondhjem Fjord. On the other hand, I have
never met with it in any of the numerous samples of plankton from the northern
part of the Ocean examined by me, for which reason we are justified in regarding
it as a true Atlantic form. Off the Norwegian coast it occurs both in the open
sea and in the fjords, being often found in considerable abundance at the very
surface of the sea. It moves rather rapidly in the usual manner, now using
chiefly the posterior antenne, now darting about in an abrupt, jerking manner
by powerful strokes of the natatory legs and the urosome.

Distribution.—Off Cape Finisterre (Kriéyer), coast of France (Canu),
British Isles (Brady), Heligoland (Claus), Mediterranean (Giesbrecht), Atlantic
Ocean from Lat. 6° S to Lat. 62° N (Cleve).

31. Centropages hamatus (Lilljeborg).
(Pl. duit).
Ichtyophorba hamata, Lilljeborg. De Crustaceis ex ordinibus tribus in Scania occurrentibus,
p. 185, Pl, XX, Ply XOOViL fies 9— 12,

Syn: Ichtyophorba angustata, Claus.

Specifie Characters.—Female. Body comparatively more slender than in the
preceding species, with the anterior division, seen dorsally, somewhat attenuated
behind. Cephalosome well defined from the 1st pedigerous segment, front tipped
below with 2 soft recurved filaments. Last segment of metasome with the

lateral parts less expanded than in OC, typicus, terminal spine shorter and

Ot

remarkably extant on right side. Genital segment slightly asymmetrical and
considerably dilated in the middle, lateral edges finely ciliated, ventral face with
a recurved spiniform process immediately in front of the genital orifice. The 2
succeeding segments of about equal size and considerably smaller than the genital
segment. Caudal rami sublinear in form, about 3 times as long as they are
broad, apical sete more elongated than in C. typicus. Anterior antenne, when
reflexed, reaching to the end of the caudal rami, none of the articulations with
dentiform projections. Legs comparatively more slender than in the type species,
with the terminal spine of outer ramus more coarsely denticulate. Last pair of
legs with the unguiform process much shorter than in that species.

Male still more slender than female, and having the lateral parts of last
pedigerous segment but slightly expanded and nearly symmetrical. Urosome fully
equalling half the length of the anterior division, though, as in the preceding
species, composed of only 4 segments. Caudal rami comparatively longer than in
female, outermost seta not transformed. Right anterior antenne with the middle
section less tumefied than in the type species, and without any dentiform projec-
tion of the antepenultimate joint. Chela of right Jast leg less powerfully developed,
thumb simple spiniform, and shorter than the dactylus.

Colour. Body in both sexes highly pellucid and nearly colourless.

Length of adult female reaching 1.35 mm., of male 1.30 mm.

Remarks,—This form was described by Prof. Lilljeborg in the year 1853
as Ichtyophorba hamata, the generic name referring to the significance of this
Calanoid as fish-food, the specific name probably to the peculiar recurved process
occurring below the genital segment in the female. The Jchtyophorba anqustata
of Claus is unquestionably indentical with Lilljeborg’s species. It may be easily
distinguished from C. typicus by its more slender body, the different form of the
lateral parts of the last pedigerous segment and of the genital segment, the soft
character of the frontal appendages, the total absence of denticles on the anterior
antenne, and, finally, by the less powerfully developed chela of the right last leg
in the male. It is, moreover, rather inferior in size.

Occurrence.—The present Calanoid occurs in great abundance in the Chri-
stiania Fjord, even in the immediate neighbourhood of the town, and is also found
pretty commonly along the whole southern and western coast of Norway, both in
the fjords and in the open sea. North of the Trondhjem Fjord it becomes more
scarce; but according to the statements of Dr. Aurivillius, it extends as far as
the 70th degree of latitude. Like the preceding species, it is a true pelagic

form, occurring, as a rule, close to the surface of the sea, and it no doubt forms

78

an essential part of the food of several pelagic fishes, for instance the herring
and the mackerel.
Distribution.—Coast of France (Canu), British Isles (Brady), Heligoland

(Claus), Kattegat (Lilleborg), the Baltic (Nordqvist), Atlantic Ocean from Lat.
41° to 66° N (Cleve).

Gen, 21. [SlaS, Boeck, 1864.

Generic Characters.—Body moderately slender, with the anterior division
somewhat tumid and much vaulted above. Cephalosome well defined from the
Ist pedigerous segment, but without any distinct cervical depression, front carrying
below 2 very delicate, recurved tentacular filaments. Last segment of metasome
confluent with the preceding one, and not expanded laterally. Urosome com-
paratively slender, especially in male, where it consists of 5 distinct segments,
the middle one conspicuously asyinmetrical. Caudal rami elongated. Eye ‘rather
large, though not protuberant below. Anterior antennze not much elongated,
otherwise of a structure similar to that in Centropages. Posterior antenne likewise
rather similar. Anterior lip with the median lobe remarkably prominent. An-
terior maxillipeds less powerfully developed than in Centropages, and having the
distal setze not prolonged. Oral parts otherwise resembling in structure those
in the above genus. Legs comparatively robust, the 3 middle pairs with the 2nd
basal joint of a somewhat unusual appearance, being obliquely oval in form;
terminal joint of outer ramus in these pairs with 3 spines outside. Last pair of
iegs in female with the inner ramus very small, uniarticulate; unguiform projection
of outer ramus well marked, though rather short; those in male with the inner
ramus obsolete on right side, outer ramus of both legs biarticulate, with the distal
joint spatulate in form and considerably larger on the right leg. No ovisac
present in female.

Remarks.—This genus, established by Boeck, was placed by Dr. Giesbrecht
in his subfamily Temorine, the subfamily Centropagime only comprising the genus
Centropages. This arrangement cannot, I think, be admitted, since the present
genus in reality exhibits a much closer relation to Centropages than to any of
the genera comprised within the subfamily Temorine, the structure of the last
pair of legs especially seeming to bring it nearer to that genus. We do not know

at present more than a single species belonging to the present genus.

32. Isias clavipes, Boeck.
(Pl. LUI, LIV).
Tsias clavipes, Boeck. Oversigt over de ved Norges Kyster iagttagne Copepoder.
Chr. Vid. Selsk. Forh. 1864, p. 242.

Syn: IJsias Bonnieri, Canu.

Specifie Characters.—Female. Anterior division of body, seen dorsally,
regularly elliptical in outline, greatest width about equalling half the length, and
occurring in the middle, anterior extremity narrowly rounded, posterior somewhat
blunted; seen laterally, considerably vaulted above. Lateral parts of last segment
of metasome rounded off. Urosome exceeding half the length of the anterior
division, and slightly asymmetrical, genital segment somewhat tortuous, with a
rounded protuberance to the left side of the dorsal face, and carrying below 2
somewhat unequal spiniform, recurved processes, one on each side of the genital
area. Caudal rami sublinear in form, being nearly 4 times as long as they are
‘broad, apical setze not much elongated. Anterior antennz, when reflexed, scarcely
reaching beyond the anterior division, some of the anterior bristles on the proximal
part spiniform. Last pair of legs with a strong spine on the hind face of the
2nd basal joint issuing near the outer corner, inner ramus very small, with 3
or 4 natatory sete; unguiform projection of outer ramus somewhat curved and
distinctly denticulated.

Male more slender than female, with the urosome longer and narrower,
middle segment produced on right side to a very conspicuous conical projection
pointing straight outwards. Right anterior antenna with the middle section mode-
rately tumefied. Last pair of legs with the inner ramus on right side obsolete,
on left transformed to a somewhat irregularly folded lamella without any sete;
distal joint of outer rami with 4 marginal spines, that of right leg much the
larger and of oval quadrangular form, with an irregular protuberance at the base
inside, and with the outermost spine very strong; that of left leg with the inner
edge finely ciliated and angularly produced both at the base and at the end.

Colour. Body, as a rule, semipellucid and of whitish colour, sometimes,
however, in female exhibiting a light bluish hue. j

Length of adult female reaching 1.35 mm., of male about the same.

Remarks.—As observed above, this is the only species of the genus as
yet known, the form described by Mr. E. Canu as Isias Bonnieri being unquestio-
nably identical with Boeck’s species. It may be easily recognized by the general
form of the body, the comparatively short anterior antenne, and the peculiar

structure of the last pair of legs, especially in the male.

80

Oceurrence.—Boeck observed this form at Karmé, west coast of Norway.
I have myself met with it in several localities both on the south and west coasts,
from the Christiania Fjord northwards at least to the Trondhjem Fjord. In
none of these localities did it occur, however, in any abundance. In habits it
seems to be less pronouncedly pelagic than the species of Centropages, being
sometimes found close to the shore among alge. On the other hand, I have
never found it in any of the samples of plankton taken in the open sea. Yet at
cannot properly be considered as a true bottom-form, as I have found it occa-
sionally, for instance, at the Zoological Station at Drébak, close to the surface
of the sea.

Distribution.— Mediterranean (Giesbrecht), coast of France (Canu), British
Isles (Brady), Atlantic Ocean between Lat. 36° and 60° N. (Giesbrecht).

Gen. 22. Limnocalanus, G. O. Sars, 1863.

Generic Characters.—Form of body slender and elongated. Cephalosome
well defined from the Ist pedigerous segment; front with 2 very small soft appen-
dages below. Last segment of metasome likewise distinctly defined from the
preceding one, its lateral parts not expanded. Urosome slender, 3-articulate in
female, 5-articulate in male. Caudal rami narrow linear, with the appendicular
bristle rather elongated. Kye small, subventral. Anterior antenne slender,
consisting in female of 25 articulations, last joint well defined, but very small;
right anterior antenna in male geniculate. Posterior antennze with both rami
slender, the outer one the longer and distinctly 7-articulate. Mandibles with
the masticatory part considerably expanded, the 2 outer denticles of the cutting
edge simple, unguiform, palp comparatively narrow, with the inner ramus reflexed.
Maxillee quite normal. Anterior maxillipeds powerfully developed, with the
distal appendages transformed to long, claw-hke spines. Posterior maxillipeds
unusually elongated. Legs slender, with the 2nd basal joint rather elongated,
inner ramus in all pairs 3-articulate, terminal joint of outer ramus with only 2
spines outside. Last pair of legs in female with the unguiform projection of the
outer ramus well marked; those in male with the outer rami biarticulate, distal
jot of left leg oblong lamellar with 4 marginal spines, that of right leg some-
what club-shaped and produced inside to a long deflexed spiniform process. No
ovisac present in female.

81

Remarks.—This genus was established by the present author as early as the
year 1863, to include a peculiar fresh-water Calanoid found in the largest Norwegian
lake, Mjésen. The name refers to the habits of this Calanoid, which somewhat
recall those of the marine Calani. It is, however, in reality very different, as
proved by the structure of the several appendages, and it does not even belong to
the same section. In the slender form of the body and the narrow elongated
caudal rami, the species of this genus resemble some of the Temorid@, especially
the genus Temorella of Claus; but the structure of the last pair of legs is very
different, and exhibits a much closer resemblance to that in the genus Centropages.
Indeed, one of the species was on this account referred to that genus by M. de
Guerne. There are, however, sufficient reasons for keeping the present genus
apart, though it must undoubtedly have a place in the family Centropagida,
as here defined. We know at present of 3 different species belonging to this
genus, viz., L. macrurus, G. O. Sars, L. Grimaldi, de Guerne, and L. sinensis,
Poppe. The first and last species have hitherto only been found in fresh-water
lakes, whereas the 2nd is a more strictly marine form, though also occurring in

the Caspian Sea. Only the first-named specie: belongs to the fauna of Norway.

33. Limnocalanus macrurus, G. O. Sars.
(Pl. LV, LVD.

Timnocalanus macrurus, G. O. Sars. Oversigt af de indenlandske Ferskvandscopepoder.
Chr. Vid. Selsk. Forh. 1862, p. 17.

Specific Characters.—Female. Anterior division of body, seen dorsally,
narrowly elliptical in outline, greatest width but slightly exceeding '/; of the length,
anterior extremity narrowly rounded, posterior somewhat contracted; seen laterally
only very slightly vaulted above. Cephalosome with a very conspicuous cervical
sinus, in front of which the dorsal margin is gibbously convex and declines
obliquely to the short rostral protuberance. Urosome (including the caudal rami)
exceeding the metasome in length, genital segment somewhat larger and thicker
than the middle one, last segment the smallest. Caudal rami narrow linear and
scarcely at all divergent, equalling in length the last 2 caudal segments combined,
their dorsal face clothed with numerous small spikes; outermost seta shorter than
the others, and issuing from the outer edge at some distance from the apical ones.
Anterior antenne, when reflexed, reaching about to the end of the middle caudal
segment. Last pair of legs with the unguiform projection of outer ramus shorter
than the terminal joint, and distinctly denticulate.

12 — Crustacea.

eee

Male of about the same size as the female, and rather similar in appearance,
though having the urosome narrower and divided into 5 well-defined segments.
Right anterior antenna with the middle section but slightly tumefied. Last pair
of legs with the outer rami very unequal, that of left leg much the longer, with
the distal joint twice as long as the proximal one, that of right leg with the
distal joint quite short, club-shaped, and carrying at the tip, outside the spiniform
process, a very small bidentate piece (rudiment of a 3rd_ joint).

Colour. Body in both sexes highly pellucid and nearly hyaline, though,
as a rule, exhibiting within the metasome a rather large oblong oil-bubble of a
clear orange hue.

Length of adult female reaching 2.20 mm.; that of male about the same.

Remarks.—This form, which, being the first one described, may be regarded
as the type of the genus, is very closely allied to the marine species, L. Grimaldi
(de Guerne), with which it has been confounded by earlier authors. On a closer
comparison, however, it is at once distinguished by the peculiar shape of the
cephalosome, as seen laterally. Whereas in L. Grimaldi the dorsal margin of
this part, as in most other Calanoids, forms an uninterrupted curve up to the
rostral prominence, in the present form it is conspicuously insinuated in the
middle, bulging out in front of the sinus almost in a gibbous manner, to join
the rostral prominence in a very oblique curve, thus giving the frontal part of
the body a very peculiar appearance. The size of the present form is also rather
inferior to that of the marine species.

Occurrence.—I have found this form very abundantly in some of the larger
Norwegian lakes, viz., Mjésen, Tyrifjord, Randsfjord, Storsjé and Femsjé. It did
not occur in any of these lakes except at some distance from the margin, and,
as a rule, not at the very surface of the water, but only at some depth below
it. In all the specimens collected (during the summer months) a large orange-
coloured oil-bubble was constantly found within the metasome, whereas the ovarial
tubes appeared, as it were, skrunk, so as to be detected only with great difficulty.
This circumstance, in connection with the fact that all the specimens taken were
fully grown, seems to prove that the propagation of this form must be confined
to a different season of the year, perhaps the winter. It has been conjectured
that this Calanoid might more properly be regarded as a relict marine form, a
supposition which, however, was chiefly based upon the erroneous confusion of the
2 nearly-allied species, LZ. macrurus and L. Grimaldu. I think, however, that we
must admit a near genealogical relationship between these 2 forms, the former
being in all probability a direct descendant of the latter, though at present it

ought to be regarded as specifically distinct. It may be worthy of note in this

connection, that the present Calanoid is only found in the lowland lakes, never

at a height of more than 130 feet above the level of the ocean.
Distribution.—The great lakes of Sweden (Lilljeborg), Finland, and Russia

(Nordquist), as also those of North America (Forbes).

Fam. 14. Diaptomide.

Characters.—Cephalosome well defined from the Ist pedigerous segment,
with a more or less distinct cervical depression above, front unarmed, or carrying
below 2 soft appendages. Last segment of metasome with the lateral parts in
female more or less expanded. Urosome comparatively short, consisting in female
of 2 or 3 segments, in male of 5 segments. Caudal rami not much prolonged,
and carrying the full number of sets. Eye distinct, subventral. Anterior antenne
in female consisting of 25 articulations; right one in male distinctly geniculate.
Posterior antenne with the outer ramus generally longer than the inner, and
distinctly 7-articulate. Oral parts on the whole normal. Posterior maxillipeds,
however, in some cases exceedingly powerfully developed. Legs comparatively
strongly built, inner ramus in Ist pair biarticulate, in the 3 succeeding pairs
3-articulate. Outer ramus of Ist pair of legs with the 2nd joint unarmed outside;
terminal joint of this ramus in the 3 middle pairs comparatively short, with only
a single spine outside. Last pair of legs in female not natatory, though distinctly
biramous, inner ramus, however, very small and simple in structure, outer ramus,
as arule, 3-articulate, penultimate joint produced at the end inside to a strong
claw-like projection, terminal joint very small, in some cases obsolete. Last pair
of legs in male very asymmetrical, right leg much the larger, and carrying at the
tip a slender, movable claw. Ovisac present in female.

Remarks.—In the restriction here adopted, this family is chiefly charac-
terised by the structure of the legs, and especially of those of the last pair in
both sexes, partly also by the shape of the urosome and the presence in the
female of a well-developed ovisac. It comprises exclusively inland forms, occurring

more generally in fresh-water lakes and ponds, but sometimes also in lakes

84

containing saline water; but no true marine forms have as yet been met with.
We know at present of at least 2 distinct genera belonging to this family, viz.,
Diaptomus, Westwood, and Paradiaptomus, G. O. Sars'). Only the former genus

is represented in the fauna of Norway.

‘Gen, 23. Diaptomus, Westwood, 1836.

Syn: Glaucea, Koch.

» Cyclopsina, M.-Edw. (part).

Generic Characters.—Body more or less slender, with the anterior division
evenly vaulted above. Cephalosome with a well-marked cervical depression at
about the middle of the dorsal face, front tipped below with 2 soft appendages
of comparatively small size. Last segment of metasome in female generally imper-
fectly separated from the preceding one, lateral parts more or less expanded, and,
as a rule, biangular, with a small denticle at each corner. Urosome in female
generally 3-articulate, genital segment much the largest, and more or less dilated
in front, middle segment small and often imperfectly separated from the anal
segment. Caudal rami not very large, with the sets scarcely transformed in male.
Anterior antenne generally slender, their length in some cases exceeding that of
the body. Posterior antennze with the outer ramus considerably longer than the
inner. Posterior maxillipeds of moderate size, terminal part 5-articulate with
none of the sete unguiform. Terminal joint of outer ramus in the Ist pair of
legs with only a single spine outside. Last pair of legs in female with the
terminal joint of the outer ramus generally distinct and carrying 2 apical spines,
those in male of somewhat varying structure in the several species.

Remarks.—This genus was established by Westwood as early as in the
year 1836. The name Glaucea of Koch seems to date from about the same year,
but Westwood’s name is that now generally accepted by carcinologists. The chief
distinguishing characters from the nearly-allied genus Paradiaptomus consist in
the presence of distinct, though small tentacular appendages to the front, the

somewhat different structure of the urosome, the fuller development of the

1) As shown by the present author, this genus is identical with the genus Broteas of
Loven; but as the latter name had been appropriated in Zoology at an earlier date, that
of Paradiaptomus ought to be restored, and according to the rules of priority, the name
Lovenula recently proposed by Dr. Schmeil must cede to that given to the genus by the
present authoi.

85

outer ramus of the posterior antenne, the much less powerful structure of the
posterior maxillipeds, the presence of only a single spine outside the terminal
joint of the outer ramus in the Ist pair of legs, and finally, the somewhat different
appearance of the last pair of legs in the female. The genus comprises a very
ereat number of species from all parts of the world, amounting to about 80 in all.
Some of these species are rather anomalous, and it is therefore very probable,
that in future it will be found advisable to subdivide this genus into several
distinct genera. ‘The determination of the species is connected with no small
difficulty, owing to the imperfect manner in which they have generally been
illustrated, most authors having contented themselves with only figuring some ana-
tomical details of each species, generally the last pair of legs in the two sexes.
To the fauna of Norway belong 7 species, to be described below. Besides some
detail-figures, I have given carefully drawn habitus-figures of both sexes of all
these, hoping thus to make the Norwegian species at least easily determinable

for students.

34. Diaptomus castor (Jurine).
(Pl. LVII, LVITI).
Monoculus castor, Jurine. Histoire des Monocles qui se trouyent aux environs de Genéve,

p. 50, Pl. IV, figs. 1, 6, Pl. V, figs. 1, 5, Pl. VI, figs. 1, 17.

Syn: Glaucea rubens, Koch.

Specific Characters.—Female. Body somewhat robust, with the anterior
division, seen dorsally, oblong oval in outline, greatest width somewhat in front
of the middle, and considerably exceeding '/; of the length, anterior extremity
obtusely rounded, posterior but slightly attenuated. Cervical depression very
conspicuous. Lateral expansions of last pedigerous segment not very large, and
divided into 2 acute lappets. Urosome distinctly 3-articulate, middle segment well
defined, genital segment somewhat asymmetrical and considerably dilated, forming
on each side a triangular expansion tipped with a short denticle, the right one
somewhat larger than the left, and placed more posteriorly. - Caudal rami com-
paratively short, about twice as long as they are broad. Anterior antenne
unusually short, when reflexed reaching but slightly beyond the anterior division
of the body. Posterior maxillipeds more robust than in most other species, 2nd
basal joint rather broad, terminal part much shorter than this joint, and having
the anteriorly-curving sets partly spiniform. Last pair of legs with a conspicuous
triangular projection on the hind face of the 1st basal joint, inner ramus some-

what shorter than the Ist joint of the outer, and distinctly biarticulate, carrying

on the tip 2 unequal spines, one of them rather slender and elongated; terminal
joint of outer ramus well defined though very small, inner apical spine about 3
times as long as the outer. Ovisac very large and oval in form.

Male considerably smaller and more slender than female, with the lateral
parts of last pedigerous segment less expanded, though, as in the female, bifurcate
at the tip. Right anterior antenna with the middle section considerably tumefied,
terminal section without any projections or denticles. Last pair of legs with the
inner ramus developed almost equally on both sides, that of right leg reaching
beyond the 1st jomt of the outer ramus, 2nd basal jot of same leg with a
hyaline lamella inside in the middle, proximal joint of outer ramus acutely pro-
duced at the end outside, distal joint with the spine of the outer edge placed in
front of the middle; apical claw very strong and evenly curved. Left leg scarcely
reaching beyond the penultimate joint of the right, terminal joint rounded, finely
ciliated inside and projecting at the tip in a quite short, digitiform process, inside
which a short blunt spine is fixed.

Colour of female generally yellowish or orange, that of male more reddish.
Usual length of adult female 2.10 mm., of male 1.90 mm.

Remarks.—This form was described as early as the year 1820 by Jurine
as Monoculus castor. The Glaucea rubens of Koch seems to be the same species,
and it is very probable that the 3 forms recorded by O. Fr. Muller as Cyclops
ceruleus, rubens and lacinulatus are also referable to the present species. It
is the largest of our Diaptomi, and is moreover easily recognized by its com-
paratively robust body, the form of the lateral expansions of the last pedigerous
segment, and that of the genital segment in the female, and finally, by the
unusually short anterior antennee.

Occurrence.—I have hitherto only met with this form in 4 localities, 3 of
which belong to the southern part of Norway, viz., Sandésund, Fredriksvern,
Merdé, whereas the 4th, Tjété, is located much farther north, on the Nordland
coast. In all 4 places it only occurred in shallow pools of small dimensions.

_ Distribution.— Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil),

Switzerland (Jurine), France (Richard), Spain (Bolivar).

87

35. Diaptomus denticornis, Wierzejski.
(PI. LIX).
Diaptomus denticornis, Wierzejski, O. krajowych skorupiaksach zrodziny Calanide. Nozgrawn
i Spraw. Wydz, matem. przyr. Akad. Unnej. Vol. XVI, p. 8.
Syn: Diaptomus castor, G. O. Sars (not Jurine).
3 gracilis var., Wierzejski.

- 7 hamatus, Lilljeborg, M. 8S.

Specific Characters.—Female. Body somewhat less robust than in D. castor,
and less stronely vaulted above. Anterior division, seen dorsally, oblong in form,
greatest width but slightly exceeding 1/; of the length, and occurring in the middle,
anterior extremity considerably contracted, posterior subtruncate. Lateral expan-
sions of last pedigerous segment rather large, biangular, outer angle more
prominent than inner. Urosome comparatively short, but slightly exceeding '/;
of the length of the anterior division, genital segment much longer than the other
2 combined, and but very slightly dilated in front, without any distinct lateral
denticles; the last 2 segments imperfectly separated dorsally. Caudal rami very
short, not nearly twice as long as they are broad. Anterior antenne, when
reflexed, reaching to about the end of the genital segment. Posterior maxillipeds
not nearly so robust as in D. castor, 2nd basal joint much narrower, terminal
part considerably exceeding this joint in length. Last pair of legs without any
prominence on the hind face of the 1st basal joimt, inner ramus very narrow,
uniarticulate, and fully as long as the Ist joint of the outer ramus, terminal
joint of the latter obsolete, and replaced by a slender spine. Ovisac large, sub-
cordate in form.

Male of the usual slender form, and having the lateral parts of last
pedigerous segment scarcely at all expanded. Right anterior antenna with the
middle section considerably tumefied, antepenultimate joint of terminal section
bordered in front by a hyaline rim projecting at the end to a triangular promi-
nence, last joint terminating in a hook-like anteriorly-curving projection. Last
pair of legs with the inuer ramus very small, that of right leg not even reaching
to the middle of the proximal joint of outer ramus, this joint obtusely produced
at the end outside, with a small denticle on the hind face of the projection,
distal joint with the spine of the outer edge situated beyond the middle, apical
claw slender and but slightly curved. Left leg scarcely projecting beyond the
penultimate joint of the right, terminal joint rounded, projecting at the end to
a short, blunt, digitiform process, on the outer side of which there is a small

simple spine.

88

Colour of female generally bluish, of male reddish orange.

Length of adult female 2.00 mm., of male 1.50 mm.

Remarks.—Vhis form was at first (in the year 1863) erroneously described
by the present author as D. castor (Jurine). The same form was subsequently
examined by Mr. Wierzejski, who at first regarded it as only a variety of
D. gracilis, G. O. Sars, but in a subsequent paper recorded it as a distinct
species under the above name. Prof. Lilljeborg assigned to this form the provi-
sional name D. hamatus, on account of the hook-like projection of the last joint
of the right anterior antenne in the male, and the name proposed by Mr. Wier-
zejski also refers to the same character. In addition to this character, the present
species may be easily recognized by the form of the lateral expansions of the
last pedigerous segment in the female, and also by that of the genital segment.
The last pair of legs, moreover, exhibit in both sexes several well-marked pecu-
liarities.

Occurrence.—I have found this form very abundantly in the neighbourhood
of Christiania, especially in small ponds, but sometimes also in larger lakes.
It also occurs in many other places in Norway, both in the lowland and in the
mountain districts, and extends northwards as far as Bodo.

Distribution.—Sweden (Lilljeborg), Tatras Mountains (Wierzejski), Switzer-
land, France (Richard), territory of Akmolinsk, Central Asia (Lepeschkin).

36. Diaptomus bacillifer, Koelbel.
(Pl. LX).
Diaptomus bacillifer, Koelbel, Carcinologisches. Sitzungsber. d. K. K, Akad. Wiss. Wien, Vol. XC.

Syn: Diaptomus montanus, Wierzejski.
= retusus, Lilljeborg, M. 8.

”

Specifie Characters.—Female. Body somewhat robust, with the anterior
division, seen dorsally, oblong oval in form, greatest width considerably exceeding
'/s of the length, and occurring somewhat in front of the middle. Lateral expansions
of last pedigerous segment somewhat resembling those in D. denticornis, hut less
distinctly biangular. Genital segment fully twice as long as the other 2 caudal
segments combined, and slightly dilated in front, with a very small denticle on each
side. Caudal rami about twice as long as they are broad. Anterior antenne,
when reflexed, reaching about to the middle of the genital segment. Last pair
of legs with the inner ramus much shorter than the Ist joint of the outer, but

distinctly biarticulate, tip blunted and somewhat incurved, with a very small hair

89

outside; terminal joint of outer ramus well defined, with the apical spines of
moderate length. Ovisac rounded.

Male considerably smaller and more slender than female, with the lateral
parts of last pedigerous segment only very slightly expanded, though on right side
distinctly biangular. Right anterior antenna in male with the middle section
moderately tumefied, antepenultimate joint of terminal section produced at the
end anteriorly to a straight rod-like process obtuse at the tip and extending
somewhat beyond the penultimate joint. Last pair of legs with the inner rami
well developed, though uniarticulate and acute at the tip, that of right leg
extending nearly to the middle of the distal joint of the outer ramus, 2nd basal
joint of this leg with a small hyaline lamella in the middle of the inner edge,
proximal joint of outer ramus produced at the end outside to a triangular pro-
jection, distal joint with the spine of the outer edge situated about in the middle,
apical claw considerably curved. Left leg extending beyond the middle of the
terminal joint of the right, 2nd basal joint with an appressed spiniform projection
inside, terminal joint produced at the end to a rather long and narrow digitiform
process, inside which stands a slender denticulated spine.

Colour of female yellowish orange, that of male dark red.

Length of adult female 1.80 mm., of male 1.40 mm.

Remarks.—In its external appearance, this form somewhat resembles D.
denticornis. On a closer examination, however, it may be easily distinguished by
the more robust form of the body, and the comparatively shorter anterior antenne,
but especially by the peculiar rod-like projection of the antepenultimate joint of
the right anterior antenna in the male. Moreover, the last pair of legs in both
sexes exhibit several well-marked differences.

Occurrence.—The only place where I have met with this form is in
the farthest north of Norway, at Vardé, Finmark. It occurred here rather
abundantly in a shallow tarn situated close to the town. In the same tarn the
arctic Phyllopod, Branchinecta paludosa, was very common, and the water was
moreover peopled with large shoals of Daphina magna.

Distribution.—Mountain lakes of Central Europe (Kcelbel, Wierzejski),
British Isles (Brady), Siberia (Lilljeborg) as far north as the New Siberian Islands
(the present author), territory of Akmolinsk (Lepeschkin).

13 — Crustacea,

90

37. Diaptomus laticeps, G. O. Sars.
(PIRInxeD):

Diaptomus laticeps, G. O. Sars. Oversigt af de indenlandske Ferskvandscopepoder.
Chr. Vid. Selsk. Forh. 1862, p. 10.

Specific Characters—Female. Body moderately slender, with the anterior
division, seen dorsally, oblong in form, greatest width somewhat exceeding '/; of
the length, and occurring quite in front, across the middle of the cephalosome,
anterior extremity broadly rounded, posterior gradually attenuated; seen laterally,
considerably dilated in front, with the dorsal margin of the cephalosome boldly
curved. Lateral expansions of last pedigerous segment comparatively small and
scarcely at all extant, outer corner distinct, inner obsolete. Genital segment more
than twice as long as the other 2 caudal segments combined, and slightly dilated in
front, with a very small denticle on each side. Caudal rami fully as long as the
last 2 caudal segments combined, and slightly widening distally. Anterior antenne,
when reflexed, extending about to the base of the caudal rami. Last pair of
legs with a well-marked triangular projection on the hind face of Ist basal joint,
inner ramus very short and uniarticulate, scarcely reaching beyond the middle of
the Ist joint of the outer ramus, terminal joint of the latter well defined, though
rather small, apical spines comparatively short. Ovisac rounded.

Male much smaller and more slender than female, resembling that of the
preceding species, but somewhat more dilated anteriorly. Right anterior antenna
with the antepenultimate joint produced at the end anteriorly to a somewhat
securiform projection extending about to the middle of the penultimate joint.
Both legs of last pair with a small hyaline lamella inside the 2nd basal joint,
inner ramus well developed, acuminate, that of right leg 1eaching beyond the
middle of the distal joint of outer ramus, proximai joint of the latter produced
at the end outside to a remarkably strong spiniform projection, distal joint with
the spine of the outer edge situated about in the middle, apical claw sharply
curved, sub-sigmoid. Left leg extending to about the middle of the terminal
joint of the right, last joint produced at the end to a very narrow and elongated
digitiform process, and carrying inside it a still longer setiform spine.

Colour generally bluish.

Length of adult female reaching 1.80 mm., of male 1.40 mm.

Remarks.—This species may be easily recognized by the strongly dilated
cephalosome, the small size of the lateral expansions of the last pedigerous seg-
ment in the female, and the structure of the last pair of legs in both sexes. The
right anterior antenna of the male is moreover distinguished by the shape of the
projection of its antepenultimate joint.

91

Oceurrence.—I have met with this form in several of the Norwegian
mountain lakes, for instance, Aursundsjé, Afsjé, Gaavelivand, Lesjevand, as also
in some lakes in the districts of Romsdal and Trondhjem; and Mr. Huitfeldt-Kaas
has recently found it in several lakes in the western part of the country.

Distribution.—Jemtland, Sweden (Lilljeborg).

38. Diaptomus laciniatus, Lilljeborg.
(Pix):

Diaptomus laciniatus, Lilljeborg, in J. de Guerne and J. Richard, Révision des Calanides d’eau
douce, p. 47, Pl. 1, figs. 22, 24, 25.

Specific Characters.— Female. Body somewhat robust of form. Anterior divi-
sion, seen dorsally, oblong oval in outline, greatest width considerably exceeding
'/; of the length and occurring somewhat in front of the middle, anterior extremity
rounded, posterior somewhat irregular. Last 2 segments of metasome confluent
dorsally, and each produced laterally {o very consp‘cuous extant linguiform lobes,
the anterior pair obtuse at the tip, the posterior acuminate. Urosome compara-
tively short, genital segment slightly dilated in front, but without any lateral
denticles. Caudal rami scarcely twice as long as they are broad. Anterior
antenn, when reflexed, extending to about the base of the caudal rami. Last
par of legs with a distinct triangular projection on the hind face of Ist basal
joint, inner ramus uniarticulate and extending almost to the end of the 1st joint
of the outer, tip acutely produced, terminal joint well defined, with the apical
spines comparatively short. Ovisac rounded and, as a rule, containing only a
limited number of ova.

Male of the usual appearance, with the last 2 pedigerous segments well
defined and not expanded laterally. Terminal part of right anterior antenna
simple, without any projection of the antepenultimate joint. Last pair of legs
with the inner edge of 2nd basal joint quite smooth, without any projecting
lamella, inner ramus of right leg somewhat larger than that of left, and extending
almost to the tip of the distal joint of the outer ramus, proximal joint of the
latter produced at the end outside to a comparatively short triangular projection,
distal joint with the spine of the outer edge situated about in the middle, apical
claw greatly curved. Left leg extending beyond the middle of the terminal joint
of the outer, last joint produced at the end to a comparatively short and blunt
digitiform process, on the inner side of which there is a similarly short spine.

Colour sometimes dark bluish, sometimes reddish orange.

Length of adult female 1.60 mm., of male 1.40 mm.

92

Remarks.—The female of this species is at once recognized by the peculiar
shape of the last 2 pedigerous segments, both of which are produced laterally to
very conspicuous, freely-projecting expansions separated on each side by a narrow
incision. Otherwise it is nearly allied to D. laticeps, differing somewhat, however,
in the structure of the last pair of legs in both sexes, as also in the total absence
of any projection on the antepenultimate joint of the right anterior antenna in
the male.

Occurrence.—Prof. Lilljeborg first found this form in a small lake situated
on the summit of the Fléifjeld near Bergen, and also received it from the Oster-
dal through Miss B. Esmark. I have myself met with it in many places in the
country, both in lowland and in mountain lakes, and, according to the recent
investigations of Mr. Huitfeldt-Kaas, it is generally distributed in the lakes of
western Norway. The most northern locality where I have found it is the
mainland opposite Vardé, Finmark. It here occurred very abundantly in shallow
tarns together with Heterocope borealis and 2 Phyllopods, viz., Branchinecta paludosa
and Polyartemia forcipata. All the specimens occurring here were of a dark
reddish orange hue, whereas those from other tracts more generally, exlibited a
bluish colour.

Distribution.—Scotland (Scott), Lake of Geneva (Cleve), Russian Lapland

and the Kola Peninsula (Lilljeborg).

39. Diaptomus gracilis, G. O. Sars.
(Pl. LXIID).

Diaptomus gracilis, G. O. Sars. Oversigt af de indenlandske Ferskvandscopepoder.
Chr. Vid. Selsk. Forh. 1862, p. 9.

Syn: Diaptomus Westwoodi, Lubbock.

Specific Character-—Female. Body very slender in form, with the anterior
division, seen dorsally, narrow oblong in form, greatest width not attaining '/; of the
length, and occurring about in the middle, anterior extremity considerably contracted,
posterior subtruncate. Lateral expansions of last pedigerous segment very distinctly
biangular, each corner tipped with an acute denticle, the outer one rather produced
and pointing straight outwards. Genital segment somewhat longer than the other 2
caudal segments combined, and gradually dilated in front, with a very conspicuous
acute denticle on each side. Caudal rami comparatively short, being scarcely
more than twice as long as they are broad. Anterior antenne exceedingly slender
and elongated, extending, when reflexed, far beyond the caudal rami, in some cases

by as much as the 4 or 5 outer joints, in other cases by only 3 of the joints.

Last pair of legs with a well-marked triangular projection on the hind face of
Ist basal joint, inner ramus uniarticulate and rather short, not extending nearly
to the end of the 1st joint of the outer ramus, terminal joint of the latter well
defined and of larger size than usual, inner apical spine rather elongated, reaching
as far as the tip of the claw-like projection of the preceding joint. Ovisac in
some cases rather large, sub-cordate, in other cases comparatively small, with only
a limited number of ova

Male still more slender than female, with the lateral parts of last
pedigerous segment less expanded, though somewhat more prominent on right
side. Right anterior antenna with the middle section not much tumefied, ante-
penultimate joint of terminal section produced at the end anteriorly to a hook-
like process, in some cases very prominent, in other cases much reduced in
size. Last pair of legs comparatively very large, with the inner rami rather
dissimilar, that of right leg being much the larger and somewhat tumefied, almost
fusiform in shape, extending far beyond the middle of the distal joint of the outer
ramus, proximal joint of the latter produced at the end outside to a comparatively
short triangular projection, distal joint very large and broad, with the spine of
the outer edge occurring somewhat in front of the middle, apical claw considerably
curved in its distal part. Left leg extending scarcely as far as the penultimate
joint of the right, inner edge of 2nd basal joint angularly produced beyond the
middle, terminal joint with a comparatively small lamellar expansion inside the
base, and gradually tapering to a simple digitiform process, inside which there
is a small seta, standing out from the joint at a right angle, and terminating in
a brush of delicate diverging cilia.

Colowr. Body generally very pellucid and almost colourless, in some
cases, however, ornamented with a broad transverse band of a chocolate hue
across the anterior division.

Length of adult female 1.40 mm., of ma'e 1.20 mm.

Remarks.—This form is easily recognizable from the 5 preceding species
by its slender form, but especially by the exceedingly elongated anterior antenne.
Moreover the shape of the lateral expansions of the last pedigerous segment in
the female, and the structure of the last pair of legs in both sexes is rather
characteristic. Two varieties of this species occur in Norway, the one with the
anterior antennze quite extraordinarily prolonged, the other with these appen-
dages somewhat shorter, but otherwise exactly agreeing with the former, no
difference whatever being found in the structure of the last pair of legs in either
of the sexes. The form described by Lubbock as D. Westwoodi seems more

properly to be referable to the latter variety.

94 =

Occurrence.—In the southern part of Norway this is one of the commonest
Diaptomi, occurring very abundantly in almost all the larger lowland Jakes, and
constituting there the essential bulk of the zoéplankton.

Distribution.—Sweden (Lilljeborg), Finland (Nordquist), British Isles (Lub-
bock), Germany (Schmeil), Switzerland (Imhof), Hungary (Daday), Italy (Pavesi).

40. Diaptomus graciloides, Lilljeborg.
(Pl. LXIV).

Diaptomus graciloides, Lilljeborg. Description de deux nouvelles espéces de Diaptomus du Nord
de Europe. Bull. Soc. Zool. France, Vol. XIII, p. 156.

Specific Characters—Female. Very like the preceding species, but some-
what less slender in form, and also of rather inferior size. Lateral parts of last
pedigerous segment but very slightly expanded and not at all extant, being
rounded off at the tip, though exhibiting the 2 usual denticles, which however are
much smaller than in D. gracilis. Genital segment rather narrow, being far less
dilated in its anterior part than in the above species, lateral denticles extremely
small. Caudal rami about as in D. gracilis Anterior antenne very slender and
elongated, reaching, when reflexed, considerably beyond the caudal rami (by about
the 2 or 3 outer joints). Last pair of legs with a very small, somewhat linguiform
projection on the hind face of the Ist basal joint, inner ramus imperfectly biarti-
culate, and reaching somewhat beyond the Ist joint of the outer ramus, terminal
joint of the latter well defined, though somewhat smaller than in D. gracilis, inner
apical spines, as in that species, very slender, extending as far as the tip of the
unguiform projection of the preceding joint. Ovisac small, with a very limited
number of ova.

Male resembling that of D. gracilis, though somewhat less slender.
Antepenultimate joint of right anterior antenna without any trace of a projection
at the end. Last pair of legs comparatively less powerful than in D. gracilis,
inner rami of about equal size and simple cylindric in form, that of right leg not
extending to the middle of the distal joint of the outer ramus, proximal joint
of the latter very slightly produced at the end outside, distal joint much smaller
than in D. gracilis, with the spine of the outer edge situated beyond the middle,
apical claw irregularly flexuous. Left leg extending far beyond the penultimate
joint of the right, inner edge of 2nd basal joint perfectly smooth, terminal joint
of a similar form to that in D. gracilis, but with the seta of the inner edge not

penicillate, and extended straight downwards.

95

Colour. Body generally very pellucid and almost colourless, in some
cases, however, of a dark bluish hue.

Length of adult female 1.30 mm., of male 1.00 mm.

Femarks.—I am by no means prepared to agree with Prof. Brady in
regarding this form as only a variety of D. gracilis. True, it is nearly allied
to this species; but on a closer comparison, several well-marked differences are
found to exist, which seem to be fairly constant and prove this form to be in
reality a well-defined species. I was also long ago aware of the existence of this
form, and had assigned to it the provisional name D. microlobatus, on account
of the small size of the lateral expansions of the last pedigerous segment in
the female.

Occurrence.—I have met with this form occasionally in the lake Femsjé,
situated at the south-eastern corner of Norway, and also not unfrequently in small
tarns at Hammerfest and at Matsjok, Finmark. According to Mr. J. Richard,
it has also been found in great abundance, by Mr. Ch. Rabot in the great lake,
Roésvand, in Nordland.

Distribution.—Sweden (Lilljeborg), British Isles (Brady), mountain lakes
of the Eifel, Germany (Zacharias), Kola Peninsula (Lilljeborg), territory of Ak-
molinsk, Central Asia (Lepeschkin).

Fam. 15. Temoride.

Characters._-Body of varying form, in some cases rather short and stout, in
other cases comparatively slender. Cephalosome well defined from the 1st pedigerous
segment, front unarmed, or provided with 2 soft tentacular appendages. Last 2
segments of metasome confluent, or at any rate imperfectly defined. Urosome
consisting in female of 3, in male of 5 segments; caudal rami of different struc-
ture in the different genera. Anterior antennz consisting in female of 24 or 25
articulations; right antenna in male distinctly geniculate. Posterior antenne and
oral parts on the whole normal. The 4 anterior pairs of legs with the joints of
the inner rami more or less reduced in number. Last pair of legs in both sexes
simple, not natatory, without any trace of inner rami; those in male, as usual,
larger than in female, and prehensile. Ovisac in some cases present, but more

frequently wanting.

96

Remarks.—This family, as defined above, is chiefly distinguished from the
Centropagide and Diaptomide by the structure of the legs, and more particularly
those of the last pair, which never are natatory, nor exhibit in either of the
sexes any trace of inner rami. In the 4 anterior pairs these rami are moreover,
as a rule, much reduced in size, constituting in some cases small uniarticulate
pieces. The family comprises as yet 7 well-defined genera, viz, Temora, Baird,
Temoropia, Scott, Temorites, G. O. Sars, Hurytemora, Giesbrecht, Heterucope,
G. O. Sars, Epischura, Forbes, and Lamellipodia, Schmeil. Of these genera, the
first 3 comprise exclusively marine species, the 4th chiefly brack-water forms,
whereas the last 3 genera are peculiar to inland lakes. In the Norwegian fauna

3 of the genera are represented, and will be treated of below.

Gen. 24. Temora, Baird, 1850.

Syn: Halitemora, Giesbrecht.

Generic Characters.—Form of body short and compact, with the anterior
division considerably vaulted above. Cephalosome remarkably dilated and exhibi-
ting at the end dorsally a gibbous prominence; front tipped with 2 very slender
and delicate, recurved tentacular appendages. Last 2 segments of metasome
confluent. Urosome with the genital segment in female comparatively short and
scarcely at all protuberant below. Caudal rami narrow and elongated, being
remarkably divaricate, and in some cases asymmetrical, setze comparatively short
and present in the normal number, the outermost one being attached to the outer
edge at some distance from the others. Eye very small. Anterior antennz
slender and elongated, composed in female of 24 articulations only, the last 2
being confluent. Posterior antennze with the outer ramus scarcely longer than
the inner, and 7-articulate. Anterior lip not much prominent, rounded below.
Oral parts of quite normal structure. Natatory legs with the inner rami com-
paratively small and biarticulate; 2nd to 4th pairs with the first 2 joints of the
outer ramus imperfectly separated in female, terminal joint with 3 spines outside,
apical spine coarsely serrate. Last pair of legs in female very small, 3-articulate,
first 2 joints simple, last one dentate at the tip; those in male very asymmetrical,
left leg much the larger, 4-articulate, and distinctly forcipate, 2nd joint being
produced inside to a long curved thumb-lke process, against which the outer part
admits of being impinged; right leg 3-articulale, with the terminal joint unguiform,

incurved. No ovisac present in female.

Copepoda

Centropagide Calanorda

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Trykti den private Usmaaling Chra

Centropages typicus, Kroyer.

Copepoda

Centropagide Calanorda

eS Shae
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Tryktiden private Opmaaling Chra
Centropages typicus, Kroyer.
(continued.)

Copepoda

BL

Calaniorda

Centropagide

Tryktiden private Opmaaling, Chra

Centropages typicus, Kroyer.

6.0. Sars autogr

(male)

a

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anorda

Copepoda
Cal

Centropages hamatus, (Lilljeb)

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Isias clavipes, Boeck.

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Calanoida

Pl LW

Centropagida

NS

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clavipes, Boeck.

(continued)

Isias

G.0. Sars auto qr.

PE EM

Copepoda
Calano:rda.

Centropagida

——

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,

Limnocalanus macrurus

6.0. Sars auto gr.

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Copepoda

Calamoraa:,

Centropagida

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G.0.Sars.

6.0. Sars auto gr.

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macrurus
(continued)

Limnocalanus

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Calanorda:

=

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castor

(Jurine,|

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.:
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Wierzeski

denticornis ,

Diaptomus

Diaptomide

G.0. Sars auto gr.

Copepoda

Calanoida.

Diaptomus bacillifer Koelbel

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laticeps ,

Diaptomus

Copepoda
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Diaptomides

SS

FIM

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laciniatus , Lilljeb.

G.0.Sars autogr

Diaptomus

cad

2

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Copepoda
Calanor

Diaptomidas

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G0. Sars autogr

6-0. Sars.

gracilis

Diaptomus

Calanoida PL LXIV.

Copepoda

Diapto mide

TAY CASS men acess , a
i BS ‘ . " \
- SS

RY ee i Hf <Q aati
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/ = = 23 |
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CSSA

SS
<< a

SS

; Tryktiden private Opmaaling, Chra
Lilljeb

Diaptomus graciloides,

G.0. Sars autogr.

AN ACCOUNT
GRUSTAGEA

OF

af ~ NORWAY
gah f WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

BY

G. O. SARS

eee : VOL. IV

COPERODA
_CALANOIDA

Ue Sh ‘ | PART IX & X
TEMORIDE, METRIDIIDE, HETERORHABDIDZ (part)

WITH 16 AUTOGRAPHIC PLATES

BERGEN :
PUBLISHED BY THE BERGEN MUSEUM
SOLD ‘BY

ALB. CAMMERMEYER’S FORLAG, CHRISTIANIA
/ 1902

97

Remarks—-The species belonging to this genus may be easily recognized
by their unusually short and compact body, and the very slender anterior antenne
and caudal rami. The name Halitemora was proposed by Dr. Giesbrecht, to
distinguish the marine species of the old genus Temora from those occurring in
brackish and fresh water, to. which the name Hurytemora was given, both these
groups being at that time considered as only subdivisions (subgenera). As, however,
their generic value is now generally accepted, the name Halitemora has been
replaced by the original name Temora, whereas the 2nd name has been retained,
to designate a distinct genus, which will be treated of farther on. We know at
present of 4 or 5 species belonging to the present genus, all of which are true
marine species. One of these belongs to the fauna of Norway, and will be

described below.

41. Temora longicornis (Miiller).
(Pl. LXV & LXVI).

Cyclops longicormis, O. Fr. Miller. Entomostraca, p. 115.

Syn: Temora finmarchica, Baird.
, Diaptomus longicaudatus, Lubbock.

, Halitemora longicornis, Giesbrecht.

Specific Characters.—Female. Anterior division of body, seen dorsally,
broadly oval in form, greatest width attaining fully half the length, and occurring
quite in front, across the middle of the cephalosome, anterior extremity obtusely
rounded, posterior gradually contracted; seen laterally, boldly vaulted above,
greatest curvature about in the middle. Cephalosome fully as long as the meta-
some, front but very slightly produced below, dorsal gibbosity small, but distinct.
Lateral parts of last segment of metasome rounded off. Urosome (comprising the
caudal rami) somewhat exceeding half the length of the anterior division, genital
and anal segments of about equal size, middle segment the smallest. Caudal
rami perfectly symmetrical and very narrow, linear, more than twice as long as
the anal segment, inner edge finely ciliated, outer edge exhibiting near the base
a small ledge; apical sete unusually short, the innermost but one much the largest
and having its base conspicuously dilated, seta of the outer edge occurring at
rather a long distance from the others and very delicate, being scarcely at all
ciliated. Anterior antennse, when reflexed, reaching about to the base of the caudal
rami. Last pair of legs with the terminal joimt about the length of the other 2

combined, and narrow oblong in form, projecting at the end into 4 about equal

14 — Crustacea,

denticles, 2 apical and 2 lateral, that of the outer edge distinctly defined at
the base.

Male more slender than female, with the anterior division of the body
less vaulted, and the urosome considerably longer and narrower. None of the
caudal sete dilated at the base. Right anterior antenna with the middle section
moderately tumefied, and exhibiting at the end anteriorly a serrated lamella. Last
pair of legs exhibiting the structure characteristic of the genus, left leg more than
twice as large as the right, with the 2nd joint greatly dilated and having the
thumb-like process long and slender, terminal joint shorter than the penultimate
one and scarcely broader, being produced at the tip to an acute projection,
outside which a ciliated seta is fixed, inner edge finely ciliated and carrying
2 small spines; right leg with the terminal joint abruptly curved near the base,
and carrying outside a strong deflexed spine.

Colour. Body semipellucid, with a faint bluish tinge, and generally
exhibiting on the anterior division some few, finely ramified pigmentary patches of
a light brown or reddish colour.

Length of adult female 1.50 mm; of male about the same.

Remarks.—This Calanoid was described as early as in the year 1785 by
O. Fr. Miiller as Cyclops longicornis. It was, however, erroneously identified by
Baird and subsequent authors with Monoculus finmarchicus of Gunnerus, which,
as shown above, is a true Calanus. The Diaptomus longicaudatus of Lubbock
seems to be the present species. Though easily recognizable from our other
Calanoids, this form exhibits great resemblance to some exotic species, especially
to Calanus turbinatus of Dana, and, indeed, Mr. Th. Scott considered it to be
the very same species. Dr. Giesbrecht, however, who seems to have had an
opportunity of examining both these forms, keeps them apart as distinct, though
very nearly allied species.

Occurrence.—This is one of our commonest Calanoids, being met with
along the whole Norwegian coast, both in the fjords and in the open sea.
Off the south and west coasts especially, it is often found in great abundance,
forming indeed an essential part of the zodplankton, and in all probability
therefore, having great significance as fish-food. In the Christiania Fjord I have
met with it during all seasons, even in the immediate neighbourhood of the town.
In habits it is a true pelagic form, occurring as a rule close to the surface of
the sea. It moves in a peculiar revolving manner, and this seems to be the
case with all the species of this genus, and may have given rise to the specific

name turbinata applied by Dana to one of them.

dg

OO

Distribution.—British Isles (Brady), coast of France (Canu), Shetland
Isles, Iceland (Cleve), Baltic (Giesbrecht), Finnish coast (Nordqvist), Atlantic
Coast of North America (Cleve), Atlantic Ocean from lat. 40° to 72° N. (Cleve).

Gen. 16. Eurytemora, Giesbrecht, 1881.

Syn: Temora (part), Lilljeborg.

» Lemorella, Claus.

Generic Characters.— Body of comparatively slender form, with the anterior
division far less tumefied than in Temora. Cephalosome, as a rule, with a gibbous
prominence at the end above, similar to that occurring in Temora, front only very
slightly prominent, and provided below with 2 extremely small, soft lappets. Last
segment of metasome defined from the preceding one by a distinct suture, its
lateral parts in some cases greatly expanded. Urosome slender, with the genital
segment in female somewhat protuberant below. Caudal rami elongated and
slightly divergent, sete present in the normal number. Eye of moderate size.
Anterior antenne comparatively short, scarcely exceeding in length the anterior
division, and in female 24-articulate; right antenna in male distinctly geniculate.
Posterior antennz with the outer ramus longer than the inner, and 7-articulate.
Anterior lip rather prominent below. Mandibles, maxillee and anterior maxillipeds
about as in Temora. Posterior maxiilipeds, however, shorter and stouter, with
the 2nd basal joint remarkably dilated, and the terminal part somewhat recurved
and clothed with delicate ciliated sete. Inner ramus of Ist pair of natatory legs
uniarticulate, that of the other pairs biarticulate; terminal joint of outer ramus
in the latter pairs with only 2 spines outside, apical spine finely denticulate on
the outer edge. Last pair of legs in female 4-articulate, penultimate joint pro-
duced inside to a strong unguiform process, last joint very small, with 2 unequal
spines on the tip; those in male rather large and less asymmetrical than in
Temora, both legs of nearly same size, 4-articulate, and more or less incurved,
terminal joint of right leg claw-shaped, that of left spatulate at the end. Ovisac
present in female.

Remarks.—The species of this genus were formerly referred to Temora;
but in the year 1881 Claus established a new genus, Temorella, for their reception.
In the same year, and at a somewhat earlier date, Dr. Giesbrecht had proposed
another name, viz., Hwrytemora, and though this name was merely used to desig-

nate a subgenus of Zemora, it has, on account of its earlier date, been preferred

100

by most recent carcinologists to that given by Claus. The genus, though evidently
belonging to the same family as Temora, differs very markedly from that genus
in several characters, among which may be named the very different structure of
the last pair of legs in both sexes. We know at present 7 or 8 species referable
to this genus, some of which have been found in brackish water, some in perfectly
fresh water, and some both in the sea and in inland lakes. To the fauna of

Norway belong 3 species, to be described below.

42. Eurytemora velox (hilljeborg).
(Pl. LXVIIT & LXVIIb).
Temora velox, Lilljeborg, Crust. de ordinibus tribus in Scania occurrentibus,
p- 177, Pl. 20, fies. 2—9 (Q).

Syn: Cyclopsina lacinulata, Fischer (not Miller).

Temora Clausii, Hoek.

Temorella Clausii, Claus.

Eurytemora lacinulata, Rich.
» Eurytemora Clausii, Brady.

» Lemorella lacinulata, G. O. Sars.

Specific Characters.—Female.—Body moderately slender, with the anterior
division, seen dorsally, oblong oval in form, greatest width not attaining half the
length, and occurring about in the middle, anterior extremity broadly rounded,
posterior scarcely at all contracted; seen laterally only slightly vaulted above.
Cephalosome scarcely longer than the 3 succeeding segments combined, and
exhibiting at the end above a well-marked knob-like prominence. Lateral parts
of last segment of metasome greatly expanded, forming broad posteriorly-extending
lamelle, each terminating in a somewhat outward-curving point, and clothed with
delicate sensory hairs. Urosome somewhat exceeding °/; of the length of the
anterior division, genital segment but slightly dilated in the middle, anal segment
of about the same length, and smooth above. Caudal rami but little longer than
the anal segment, and clothed both inside and dorsally with delicate hairs; caudal
setee unusually short and conspicuously dilated at the base, that of the outer edge
occurring not far from the others. Anterior antennze, when reflexed, reaching
about to the end of the anterior division of the body, and rather richly supplied
with bristles. Last pair of legs with the penultimate joint armed outside with a
single spine only, claw-like process comparatively short and distinctly denticulated
outside, extending obliquely backwards. Ovisac large, rounded.

Male considerably more slender than female, and having the lateral parts

of last segment of metasome simple, rounded. Urosome rather narrow and

elongated; caudal rami equalling in length the last 2 segments combined, and
having the apical setze more elongated than in female. Right anterior antenna
rather strongly built, with the middle section considerably tumefied. Last pair
of legs with the 2nd joint but slightly dilated, terminal joint of both legs exhi-
biting a slight median subdivision, that of left leg terminating in 2 obtuse lobes.

Colour. Body more or less pellucid, in some cases, however, tinged with
yellowish brown.

Length of adult female reaching to 2.20 mm., that of male to 1.85 mm.

Remarks.—This form was first described (in the year 1853) by Seb.
Fischer under the name of Cyclopsina lacinulata, being regarded as identical with
O. Fr. Miiller’s Cyclops lacinulatus, which, however, is evidently a very different
form, and is probably referable to Diaptomus castor Jurine. The same species
was subsequently observed by Prof. Lilljeborg, who described it as a new species
of the genus Temoru (T. velox). It is, however, only the female that is referable
to the present species, whereas the male described by Prof. Lilljeborg belongs
to another nearly-allied species, to be described farther on. The Temora Clausii
of Hoek is unquestionably the present form. It is the largest of the known
species, and moreover easily recognizable, at any rate in the female sex, by the
peculiar form of the lateral expansions of the last segment of the metasome, as
also by the less elongated caudal rami.

Occurrence. —I have found this form rather abundantly in small pools on
2 islands lying off Arendal. The pools were located at only a short distance
from the shore, and it is very probable therefore that at times the water is
mingled with sea-spray. This is evident from the circumstance that in the same
pools the well-known Harpacticid, Tigriopus fulvus Fischer, occurred very plenti-
fully. I have, however, met with this Calanoid also in perfectly iresh water,
for instance in the Vansjo at Moss, and in tranquil creeks of the river Glommen
(at Nipen), many miles from its mouth. The specimens in these places, however,
were of far inferior size to those found in the brackish pools, and also much
more pellucid. The animal moves very rapidly in abrupt bounds, and thus fully
deserves the specific name given to the species by Prof. Lilljeborg.

Distribution.—Russia (Fischer), Germany (Schmeil), Britany (Brady),
France (Richard), Holland (Hoek), Skane (Lilljeborg), the Baltic (Nordqvist),

fresh-water estuaries of the Caspian Sea (the present author)

43. Eurytemora hirundoides (Nordqvist).
(Pl, LX@X):
Temorella affinis, var. hirwndoides, Nordqvist. Die Calaniden Finlands, p. 48, Pl. IV,
figs. D—Ul = Pls Ve ng.o:
Syn: Temora velox, Lilljeborg oo.

» Lemora imermis, Boeck (immature).

Specific Characters.—Female.—Body exceedingly slender, with the ante-
rior division, seen dorsally, narrow oblong in form, greatest width about
equalling '/; of the length, and occurring somewhat in front of the middle,
anterior extremity narrowly rounded, posterior slightly contracted. Cephalosome
somewhat exceeding in length the 3 succeeding segments combined, and exhibiting a
well-marked dorsal prominence behind. Last segment of metasome with the lateral
parts expanded into triangular, somewhat divergent lamelle, which, however,
do not extend as far as the genital segment. The latter somewhat dilated in
the middle, and abruptly contracted behind. Anal segment fully as long as the
genital segment, and clothed dorsally with delicate spikes. Caudal rami very
slender and elongated, somewhat exceeding in length the last 2 caudal segments
combined, and, like the anal segment, clothed dorsally with delicate spikes, apical
sete comparatively more elongated than in E. velox, that of the outer edge situated
at rather a long distance. from the others. Anterior antenne, when reflexed,
reaching scarcely to the end of the anterior division. Natatory legs considerably
more slender than in FE. velox, otherwise of same structure. Last pair of legs
with the penultimate joint armed outside with 2 slender spines, unguiform process
comparatively larger than in E, velox, and quite smooth, extending obliquely
backwards. Ovisac large, oblong oval in form.

Male still more slender than female, and, as usual, having the last seg-
ment of metasome simple, not expanded laterally. Right anterior antenna with
the middle section considerably tumefied. Last pair of Iegs with the 2nd joint
on both sides conspicuously dilated, exhibiting inside a rounded expansion, terminal
jot without any median subdivision, that of right leg conspicuously dilated
at the base, that of left leg terminating in 3 lobules with a hollow space
between them.

Colowr.—Body in both sexes highly pellucid and almost colourless.

Length of adult female reaching to 1.15 mm.

Remarks.—This form has generally been considered as only a variety of
EK. affis, Poppe. In my opinion, however, it ought to be specifically distinguished
with fully as much reason as the 3 forms, EH. hirundo, Giesbrecht, F. lacustris,

Poppe, and . gracilis, G. O. Sars. All the 4 species are certainly very closely

a

103

related, and in all probability stand in a close genealogical relation to each other;
but as long as no distinct transitions between them have been demonstrated to
exist, they must be kept apart. The true EL. affinis, Poppe, of which I have had
specimens for examination, is a much more robust form, and differs moreover,
at any rate in the female sex, in the larger size of the lateral expansions of the
last segment of the metasome, as also in the shape of the genital segment. ‘The
specimen described by Prof. Lilljeborg as the male of his Temora velox, is
undoubtedly referable to the present species, and this is also the case with the
form recorded by Boeck as Temora velox, and that named T’. inermis, the latter
supposed species being only founded on immature specimens, in which the lateral
expansions of the last segment of the metasome have not yet been formed.
Occurrence.—I have found this form both in the sea and in brackish
lakes and ditches round the greater part of the Norwegian coast. On the other
hand, I have never met with it in perfectly fresh water. At the Zoological Station
at Drébak, it is often taken close to the shore in comparatively salt water, and
I have also occasionally found it in plankton-samples taken in the Brevik Fjord.
I have come across it in quite extraordinary abundance in a brackish lake at
Kolvereid, Namdal, and this is the most northerly place where I have observed it.

Distribution.—Skane (Lilljeborg), Finnish coast (Nordqvist).

44. Eurytemora lacustris, Poppe.
(Pl. LXX).
Temorella lacustris, Poppe, Zeitschr. f. wiss. Zool. Vol. 45, p. 278, Pl. 15, figs. 1O—13.

Syn: Temorella intermedia, Nordqvist.

Specific Characters—Female. Body somewhat less slender than in HF.
hivundoides, with the anterior division, seen dorsally, oblong oval in form, greatest
width exceeding '/; of the length and occurring quite in front, across the middle
of the cephalosome, anterior extremity rounded, posterior somewhat contracted.
Cephalosome occupying about half the length of the anterior division, and exhi-
biting in the middle dorsally a slight cervical depression, and at the end a
well-marked knob-like prominence. Last segment of metasome scarcely at all
expanded laterally. Urosome rather siender, genital segment but slightly dilated
in the middle, anal segment fully as long, but much narrower, and perfectly
smooth above. Caudal rami not quite attaining the length of the 2 preceding
segments combined, but like them smooth above; sete of moderate length, that

of the outer edge scarcely shorter than the others, and situated at rather a long

104

distance from them. Anterior antenne, when reflexed, reaching to about the end
of the anterior division of the body. Natatory legs exactly as in EL. hirundoides.
Last pair of legs with the penultimate joint armed outside, as in E. hirundoides,
with 2 spines, which however are considerably shorter; outer apical spine likewise
shorter than in the said species; unguiform process rather strong and extending
straight inwards, at a right angle with the axis of the leg. Ovisac of moderate
size, rounded.

Male resembling that of EF. hirundoides, but differing slightly in the
structure of the last pair of legs, the 2nd joint of which is less dilated; terminal
joint of right leg very slender, being scarcely at all dilated at the base, that of
left leg terminating in 2 rounded lobes.

Colouv.—Body in both sexes highly pellucid and almost colourless.

Length of adult female 1.30 mm.

Remarks.—This form was first described by Poppe as Temorella lacustris,
and was subsequently recorded by Nordqvist under another specific name, viz.,
T. intermedia. It is closely allied to E. hivundoides, though differing conspicuously
in the simple structure of the last segment of the metasome, which does not form
any lamellar expansions in the adult female. Moreover the delicate spikes with
which the anal segment and the caudal rami in FE. hirundoides are clothed, are
wanting here. Finally, the last pair of legs exhibit in both sexes some small

differences referred to in the above diagnosis.

Occurrence.—I have hitherto only found this form in a single locality,

viz., in the Femsjé, where some few specimens were captured. It is never found

except in perfectly fresh water; hence the specific name proposed by Poppe.
Distribution.—Sweden (Lilljeborg), northern Germany (Poppe), Finland

(Nordqvist), Ladoga (idem).

Gen. 17. Heterocope, G. 0. Sars, 1863.

Generic Characters.—Body more or less robust, with the anterior division
moderately vaulted above. Cephalosome somewhat expanded in the middle and
having above a distinct cervical depression, front quite unarmed below. Last
segment of metasome confluent with the preceding one, and without any lateral
expansions. Urosome moderately slender, genital segment in female much the

largest and more or less protuberant below. Caudal rami comparatively short

105

and broad, transversely truncated at the tip, setae much reduced in number, only
3 on each ramus being fully developed. Kye rather large and situated far
forward. Anterior antenne slender, and composed in female of 25 articulations,
the last rather small, but well defined from the preceding one; right anterior
antenna in male geniculate. Posterior antenne with the outer ramus much nar-
rower than the inner, and composed of 6 joints only. Anterior lip comparatively
large and broad, with the median lobe densely hairy. Mandibles with the cutting
teeth simple, not bidentate, palp with the inner ramus much longer than the
outer. Maxille normal. Maxillipeds rather strongly built, the anterior ones with
the terminal appendages claw-like. though comparatively short; the posterior ones
with the Ist basal joint comparatively broad, and carrying anteriorly unusaally
strong set, terminal part composed of 4 joints only. Inner ramus of all the
natatory legs very small and uniarticulate, terminal joint of outer ramus with
only 2 spines outside, apical spine in 2nd to 4th pairs coarsely serrate on the
outer edge. Last pair of legs in female 4-articulate, 1st joint confluent with that
on the other side, terminal joint of different form in the different species and
coarsely dentate, apical deunticle generally much elongated and claw-like; those in
male on the whole built upon the same type as in the genus Temora, the left leg
being much the larger, and having a long curved, thumb-like process issuing from
inside the 2nd joint. Ovisac in female wanting, or at any rate imperfectly
developed. )

Remarks.—This genus was established in the year 1863 by the present
author, to comprise 2 Norwegian fresh-water Calanoids, one of which had been
described at a somewhat earlier date by Prof. Lilljeborg as a species of Diap-
tomus. The genus is unquestionably referable to the family Temorid@, as here
defined, the last pair of legs in particular exhibiting an evident resemblance in
their structure to those in the typical genus Temora. Yet this genus is clearly
characterised both from Temora and the other genera comprised in this family
by several pecularities, among which may be mentioned the rudimentary condition
of the inner ramus of the natatory legs, a character which has given rise to the
generic name. We know at present 4 species of this genus, one of which has
been found in the Caspian Sea, whereas the other 3 are true fresh-water forms.
These 3 species belong to the fauna of Norway, and will be described below.

15 — Crustacea.

45. Heterocope saliens (Lilljeborg).
(Pl. LXXI & LXXtI).
Diaptomus saliens, Lilljeborg. Ofvers. Vet. Akad. Férh. Vol. 19, p. 395, Pl. 3, figs. 18—81.
Syn: Heterocope robusta, G. O. Sars.
53 — alpina, G. O. Sars (immature).

— romana, Imhof.

Specific Characters.— Female. Body comparatively robust, with the anterior
division, seen dorsally, oblong oval in form, greatest width not attaining half the
length, and occurring about in the middle, anterior extremity abruptly contracted
and obtusely truncated at the tip, posterior slightly attenuated. Urosome scarcely
attaining half the length of the anterior division, genital segment about the length
of the other 2 combined, and having the genital protuberance simple, without any
spines or appendages, anal segment shorter than the middle one. Caudal rami
about the length of the anal segment, and scarcely widening distally, each carrying
outside the 3 apical sete a small unciliated bristle, not attaining the length of
the ramus. Anterior antenne, when reflexed, reaching somewhat beyond the 2nd
caudal segment. Last pair of legs with the terminal joint considerably dilated,
lamellar, carrying outside 2 spinules, inside 4 distinctly bidentate denticles,
apical spine very long and coarsely denticulate in its distal part.

Male of about the same size as the female, and not very different in shape,
though the urosome is comparatively more slender, and, as usual, 5-articulate.
Right anterior antenna with the middle section but slightly tumefied. Natatory
legs of same structure as in the female. Right last leg with the outer 2 joints
well defined, and together. about the length of the antepenultimate one, the
latter without any protuberance of the inner edge; terminal joint of left leg
oblong oval in form, about 3 times as long as it is broad, and finely ciliated
inside, inner apical spine rather elongated.

Colouwr.—Body generally of a beautiful ultramarine hue, antennz, oral
parts and urosome often tinged with dark orange.

Length of adult female about 3 mm.

Remarks.—As stated above, this form was first described by Prof. Lillje-
borg as Diaptomus saliens, and the same form was somewhat later recorded by
the present author under the name of Heterocope robusta, Prof. Lilljeborg’s paper
being at that time unknown to him. The Heterocope romana of Imhof is unque-
stionably the same species, and this is also the case with the form recorded by
the present author as H. alpina, which was only founded on immature specimens
of H. saliens. It may be regarded as the type of the present genus.

(107

Occurrence.—I have met with this beautiful Calanoid in many places in
Norway, in the lowland, and especially in the mountain lakes. According to the
recent investigations of Mr. Huitfeldt-Kaas, it is generally distributed in almost
all the lakes of the western part of Norway, and it has been found occasionally
by Mr. Rabot in the great lake Résvand in Nordland. The most northerly place
where I have met with it, is at Bodé, located somewhat north of the Arctic
Circle. As a rule, it is found as a true limnetic form in larger lakes, where it
constitutes an essential food of the trout; but occasionally it also occurs in
comparatively small tarns and ditches. It moves in a peculiar jerky manner,
chiefly by rhythmical strokes of the posterior antenne, only now and then making
a quick bound by employing its natatory legs and urosome. ‘The specific name
proposed by Prof. Lilljeborg refers to this peculiar motion.

Distribution.—Lakes of Sweden (Lilljeborg), Russia (Poggenpol), ‘central
Germany (Gruber, etc.), Bohemia (Fric), North Italy (Pavesi), Switzerland (Imhof).

46. Heterocope borealis (Fischer).
(Pl. LXXII).

Cyclopsina borealis, Fischer, in ,.Middendorf’s Sibirische Reise“. Zool. p. 158.
Pl. VIL, figs. 40—46.

Syn: Heterocope robusta, Gruber (not G. O. Sars).
“ — saliens, Nordqvist (not Lilljeborg).

- — Weismanni, Imhof.

Specific Characters.— Female. Body considerably more robust than in the
preceding species, with the anterior division, seen dorsally, oval in form, greatest
width nearly attaining half the length, and occurring about in the middle. Uro-
some about the length of the metasome, genital segment fully as long as the
other 2 combined, hind part of genital area with a slight incurved dentiform
projection on each side, anal segment shorter than the middle one. Caudal rami
short and broad, widening distally, and slightly divergent, apical sets conspi-
cuously dilated at the base, the middle one somewhat longer than the other 2,
bristle outside them comparatively larger than in H. saliens, attaining the length
of the caudal rami. Anterior antennz, when reflexed, reaching but little beyond
the genital segment. Last pair of legs with the terminal joint comparatively
narrower than in H. saliens, and having the denticles of the inner edge less
distinctly bidentate, apical spine very slender.

Male resembling that of H. saliens, but more robust of form, with the

middle section of right anterior antenna more tumefied. Outer ramus of 2nd to

108

4th pairs of legs peculiarly transformed on right side. Last pair of legs on the
whole resembling those in the male of H. saliens, though exhibiting some small
differences: right leg with the 2nd joint produced inside to a knob-like prominence,
the last 2 joints imperfectly defined from each other; left leg with the terminal
joint comparatively narrower and more elongated, exceeding in length the 2 pre-
ceding joints combined. j

Colowr.—Body generally of a dark olivaceous hue, anterior antenne and
caudal rami tinged with reddish brown. 4

Length of adult female somewhat exceeding 3 mm.

Remarks.—There cannot in my opinion be any doubt that this is the
Cyclopsina borealis originally described by Seb. Fischer, since, as shown by the
present author, it is the only species of Heterocope occurring in the tract from
which Fischer received his material. Owing to the imperfect description given
by that author, it was not recognized, however, by subsequent carcinologists, and
in the year 1890 it was re-described by Dr. Imhof as a new species under the
name of H. Weismanni. By some other authors (Nordqvist, Gruber) it was
confounded with A. saliens, Lilljeb., to which species it certainly bears a great
resemblance. On a closer comparison, however, it may be easily distinguished
by its considerably more robust body, the comparatively shorter anterior antenne,
and also by some slight differences in the structure of the caudal rami and the
last pair of legs in both sexes. A character quite peculiar to the present
species, and not found in any other known Calanoid, has been first pointed out
by Dr. Gruber, viz., the peculiar transformation in the male of the outer ramus
on the right side of the 2nd to 4th pairs of legs. This transformation is perfectly
constant, and will alone suffice to distinguish the male of the present species.

Occurrence.—I have only met with this form in the eastern part of Fin-
mark, where it seems to be generally distributed in smail tarns and ditches. It
occurs in this way in great abundance on the mainland opposite Vardé, as also
at Matsjok, an affluent to the river Tana. In habits it agrees with H. saliens,
moving in a similar jerky manner.

Dstribution.—Siberia, in the rivers Taimyr and Boganida (Fischer), Iana
territory, New Siberian Islands, territory of Akmolinsk (the present author), Kola

Peninsula and Nova Zembla (Lilljeborg), Bodensee (Imhof).

so 109

47. Heterocope appendiculata, G. O. Sars.
(Pl. LXXIV).

Heterocope appendiculata, G. O. Sars. Oversigt af de indenlandske Ferskvandscopepoder.
Chr. Vid. Selsk. Forh. 1862, p. 15.

Specific Characters.—Female. Body considerably more slender than in
the 2 preceding species, with the anterior division, seen dorsally, oblong in form,
sreatest width but slightly exceeding 1/; of the length, and occurrmg somewhat
in front of the middle. Urosome exceeding half the length of the anterior division,
genital segment shorter than the other 2 combined, and carrying in front of the
genital orifice a transverse row of 8 peculiar, reflexed appendages; anal segment
longer than the middle one. Caudal rami about twice as long as they are broad,
bristle at the outer corner wanting, and replaced by a slight dentiform projection.
Anterior antenne very slender and elongated, reaching, when reflexed, beyond the
caudal rami. Last pair of legs with the terminal joint very narrow, denticles of
the inner edge simple, apical spine very slender.

Male still more slender than female, and having the middle section of
right anterior antenna only slightly tumefied. Last pair of legs differing con-
spicuously from those in the 2 preceding species, right leg rather produced and
peculiarly contorted, having the 3 outer joints confluent into a falciform piece;
left leg with the thumb-like process bulbously dilated at the tip, terminal joint
rather narrow, with the apical spine quite short.

Colowr.—Body semipellucid and generally of a light bluish green hue,
anterior antenne and urosome in male tinged with orange.

Length of adult female 2.20 mm.

Remarks.—This species may at once be distinguished from the 2 pre-
ceding ones by its more slender form of body, the greatly elongated anterior
antenne, and the peculiar appendages occurring in front of the female genital
orifice, the latter character having given rise to the specific name. It is also
rather inferior in size to the other 2 Norwegian species, and exhibits a somewhat
different structure in the last pair of legs.

Occurrence.—In the southern part of Norway, this species is by far the
commonest, occurring in great abundance in almost all the larger lakes, and
there constituting an essential part of the food of several fresh-water fishes.
In the northern and western parts of the country, as also in the mountain lakes,
its place is taken by H. saliens, with which it agrees perfectly in habits.

Distribution.—Sweden (Lilljeborg), Finland (Nordqvist), Ladoga (idem),
Northern Germany (Zacharias), Russian Lapland (Richard).

110

Fam. 16. Metridiide.

Characters.—Body of comparatively slender form, with the cephalosome
well defined from the Ist pedigerous segment, front somewhat produced and
carrying below 2 delicate, ciliated filaments. Last 2 segments of metasome united.
Urosome more or less elongated, and consisting in female of 3, im male of 5
segments. Caudal rami comparatively broad, flattened, with the full number of
sete. Eye very small, subventral. Anterior antenne moderately slender, and
consisting in female of 24 articulations, the 7th and 8th being united; left antenna
in male, as a rule geniculate, and richly supplied with sensory appendages. Posterior
antennz and oral parts on the whole normal. The 4 anterior pairs of legs with
both rami 3-articulate, outer ramus of 2nd to 4th pairs very large, more or less
lamellar, with comparatively short spines, 3 of which occur outside the terminal
joint. Inner ramus of 2nd pair with the Ist joint peculiarly transformed. Last
pair of legs simple, not natatory, being very small in female, in male, as usual,
somewhat larger and prehensile, right leg the larger. No ovisac present im female.

Remarks.—In this new family I propose to include the 2 nearly-allied
genera Metridia, Boeck and Plewromamma, Giesbrecht. These genera, it is true,
in some respects apparently exhibit a close resemblance to the Temoride; but
the structure of the natatory legs is essentially different, and more resembles that
in the next family (Heterorhabdide). With this family they also agree in the
circumstance that the left anterior antenna in the male is generally prehensile.
Finally, a peculiarity, not mentioned in the above diagnosis, may be here named,
viz.,- the luminous power of the animal, when alive. This power seems to be
common to all the Metridiide, whereas it has not been observed in any other
Calanoids. In one of the genera (Plewromamma), a special luminous organ is
present, and though this organ is wanting in Metridia, all the species of that
genus observed in the living state, have been found to emit light when disturbed.
Both genera are represented in the fauna of Norway, and will be treated
of below.

Gen. 18. Metridia, Boeck, 1864.

Generic Characters.—Body slender and elongated, with the anterior divi-
sion only slightly tumefied. Cephalosome without any cervical depression above,

rostral projection smooth in front, tentacular filaments very slender. Lateral

111

parts of last segment of metasome not expanded, though in some cases angular
at the tip. Urosome narrow and elongated, genital segment scarcely at all
protuberant below, anal segment slightly widening distally. Caudal rami flattened,
with the sets comparatively short, one of them attached to the outer edge, at
some distance from the others. No special luminous organ present. Anterior
antenne conspicuously attenuated, with some of the proximal joints projecting
into small denticles, last joint very small, but well defined from the preceding
one, which carries anteriorly an unusually long and slender bristle; prehensile
antenna of male (generally the left) with the sensory appendages of moderate
size and uniform appearance. Posterior antennze with the outer ramus scarcely
longer than the inner, and 6-articulate. Anterior lip somewhat prominent, and
defined in front by a slight sinus. Posterior maxillipeds very slender, with the
terminal part 5-articulate and longer than the 2nd basal joint. Inner ramus of
2nd to 4th pairs of legs about half the length of the outer, its terminal joint
with 2 setz on the outer edge, Ist joint in 2nd pair with strong hamiform pro-
cesses inside; outer ramus of these pairs moderately dilated, with the apical
spine well developed and finely denticulate on the outer edge; its 1st joint in
3rd_ pair somewhat larger than in the otler pairs, and having a small incision
at the end outside. Last pair of legs in female 3- or 4-articulate, with slender
sete at the tip; those in male 5-articulate and more or less strongly incurved,
right leg with the terminal joint but slightly dilated, antepenultimale joint, as a
rule, with a slender spiniform process inside.

Remarks.—This genus was established in the year 1864 by Boeck, to
comprise 2 Norwegian species, and its near relation to the genus Plewromma of
Claus (= Pleuwromamma, Giesbr.) was at the same time mentioned. The chief
distinction between these 2 genera consists in the presence or absence of a
special luminous organ, the latter being constantly found in the genus Plewro-
mamma, whereas in Metridia no such organ exists. In addition to this character,
some other differences may, on a closer comparison, be demonstrated to exist,
justifying the separation of these 2 genera, the more so as several species of
each of them have been found. We know at present no less than 9 species
referable to the present genus, 2 of which belong to the Norwegian fauna and

will be described below.

jo

48. Metridia longa (Lubbock).
(Pl. LXXV & LXXVD.

Calanus longus, Lubbock. On some Arctic Species of Calanide, Ann. nat. hist., ser. 2,
Vol. 14, <p); 127,eRl05; hes LO:

Syn: Metridia armata, Boeck.

Specific Characters.— Female. Body exceedingly slender, with the anterior
division, seen dorsally, oblong in form, greatest width but slightly exceeding '/;
of the length, and occurring about in the middle, anterior extremity somewhat
contracted and narrowly rounded at the tip, posterior gradually attenuated.
Cephalosome much shorter than metasome, and having the dorsal face quite
evenly vaulted, rostral projection somewhat prominent. Lateral parts of last
segment of metasome rounded off at the tip. Urosome very slender, exceeding
in length the metasome, genital segment about the length of the other 2 com-
bined, and only very slightly dilated in front. Caudal rami comparatively large,
fully as long as the anal segment, and somewhat widening distally, apical sete
rather short, the innermost but one the longest, seta of the outer edge occurring
at about °/; of the length of the caudal ramus. Anterior antenne, when reflexed,
reaching about to the middle of the genital segment, Ist, 2nd, 4th, 5th, 6th
and 10th joints each produced at the end anteriorly to a small dentiform
projection. Last pair of legs distinctly 4-articulate, last joint the smallest,
and carrying 3 slender ciliated sete, the innermost the longest, and extending
obliquely inwards.

Male rather smaller than female and still more slender, with the urosome
very narrow and elongated. Left anterior antenne (more rarely the right)
geniculate, with the middle section only slightly tumefied. Last pair of legs
exhibiting the structure characteristic of the genus, terminal joint of both legs
oblong in form, with the distal part somewhat contracted, spiniform process of
antepenultimate joint of right leg rather elongated, slightly sigmoid and finely
denticulated on one side distally. '

Colour.—Body in both sexes highly pellucid, almost hyaline, sometimes
with a slight brimstone-coloured shade on the anterior part of the cephalosome.

Length of adult female reaching to 4.30 mm., of male to 3.70 mm.

Remarks.—This form was described, though rather imperfectly, by Lubbock
im the year 1854 as Calanus longus. The same form was subsequently found
off the Norwegian coast by Boeck, who describes it as Metridia armata, the
specific name being probably derived from the dentiform projections which some

of the articulations of the anterior antenne form in front. It may be regarded

113
as the type of the genus, and is easily recognizable from most other Calanoids
by its very slender and elongated form.

Occurrence.—I have met with this form along the whole Norwegian coast,
from the Christiania Fjord to Vadsé, but as a rule only in greater depths, below
100 fathoms. This form often occurs in great abundance, especially in the
deep fjords; and it was also found rather frequently in some of the samples of
plankton taken from deep water in the open sea during the cruise of the “Mi-
chael Sars”. In the living state it is so exceedingly pellucid, that in spite of its
comparatively large size, it is not easy to detect. It moves in the usual manner,
now proceeding at quite an even rate by rapid vibrations of the posterior antenne,
now jumping along abruptly by powerful strokes of the natatory legs and urosome.
When disturbed, it sends out from its body a bright flash of a bluish colour. ‘This
flash is so intense, that even by full day-light it can easily be seen.

Distribution.—Faroe Channel (Norman), Baffin’s Bay (Hansen), Spitsbergen
(Lilljeborg), the Kara Sea (Hansen), Polar basin crossed by Nansen (the present
author), Atlantic Ocean from lat. 56° to 76° N. (Giesbrecht).

49. Metridia lucens, Boeck.
(Pl. LXXVII).

Metridia lucens, Boeck. Oversigt over de ved Norges Kyster forekomne Copepoder.
Chr. Vid. Selsk. Forh. 1864, p. 238.

Syn: Metridia armata, Brady (not Boeck).
, Paracalanus hibernicus, Brady & Roberts.

» Metridia hibernica, Giesbrecht.

Specific Characters.—Female. Body somewhat less slender than in the
preceding species. Cephalosome about the length of the metasome. and remarkably
vaulted above in the middle. rostral projection less prominent than in M. longa.
Lateral parts of last segment of metasome acutangular at the tip. Urosome
comparatively shorter than in MV. longa, genital segment not attaining the length
of the other 2 combined. Caudal rami scarcely as long as the anal segment,
and of nearly uniform breadth throughout, outermost seta situated about in the
middle of the outer edge. Anterior antenne, when reflexed, reaching but slightly
beyond the anterior division of the body, structure about as in JZ. longa, except
that the dentiform projection is wanting in the 10th articulation. Last pair of
legs composed of only 3 joints, the last 2 being united.

Male resembling that of M. longa, but having the cephalosome more
strongly vaulted above. Left anterior antenna (more rarely the right) geniculate.

16 — Crustacea.

114

Last pair of legs of a structure similar to that in M. longa, but with the
terminal joint on both legs less attenuated distally.

Colour.— Body in both sexes highly pellucid, and almost colourless.

Length of adult female 2.50 mm., of male 2.30 mm.

Remarks.—This form is closely allied to MW. longa, but is of much inferior
size, and moreover easily distinguissed by its somewhat less slender form, the
shorter caudal rami, and the much more strongly vaulted cephalosome. Finally,
the last pair of legs in the female are only 3-articulate, the outer 2 joints being
confluent. The form described by Brady in his work on the British Copepoda
as M. armata is unquestionably the present species. It was subsequently recorded
by the same author under another name, viz., Paracalanus hibernicus, and Dr.
Giesbrecht in his great work records it as Metridia hibernica, not being at that
time aware of its identity with Boeck’s species.

Occurrence.—Whereas MM. longa must be regarded as a true wah ctic form,
the present species is evidently of a more southern range. I have found it rather
commonly along the south and west coasts of Norway and, unlike what is the
case with M. longa, it is often met with near the surface of the sea. It extends
northwards at least to the Lofoten Islands, and it was also found in some of the
plankton-samples taken in the open sea during the cruise of the “Michael Sars”.
On the other hand, I have never found it in any samples from the Arctic Ocean.
The luminous property of this form is mentioned by Boeck, who for this reason
proposed for it the specific name /ucens.

Distribution.—British Isles (Brady), Iceland, Faroe Channel (Norman),
Atlantic Ocean between lat. 50° and 62°N. (Cleve).

Gen. 19. Pleuromamma, Giesbrecht, 1898.

Syn: Plewromma, Claus (not Doneschall).

Generic Characters.—Form of body generally less slender than in Metridia,
in some cases rather different in the two sexes. Cephalosome with a very conspi-
cuous dark-coloured mammilliform knob (luminous organ) on right side, at the base
of the posterior maxillipeds, rostral prominence generally with 1 or 2 dentiform
ledges in front, tentacular appendages shorter than in Metridia. Lateral parts
of last segment of metasome rounded off. Urosome less slender than in Metridia,

with the genital segment in female considerably protuberant below; anal segment

115

somewhat flattened, widening distally, and projecting on each side in a conspicuous
angular corner. Caudal rami comparatively smaller than in Metridia. Anterior
antenne resembling in structure those in the above-named genus, some of the
proximal articulations being produced as more or less conspicuous dentiform pro-
jections, generally wanting in male; left antenna in the latter as a rule geniculate,
and having the proximal sensory appendages very large, leaf-like. Posterior
antenne with the outer ramus longer than the inner, and distinctly 7-articulate.
Anterior lip. rather prominent and defined in front by a deep transverse sinus. Oral
parts scarcely differing in their structure from those in Metridia. Natatory legs,
on the other hand, much more strongly built, with the outer ramus of 2nd to 4ht
pairs very large and expanded, with comparatively short spines and scte; that
of 3rd pair with a very deep incision at the end of the Ist joint. Inner ramus
in these pairs not attaining half the length of the outer, and having only a
single seta outside the terminal joint; that of 2nd pair with the 1st jomt distinctly
hooked inside. Last pair of legs in female 2- or 4-articulate; those in male
5-articulate, with the terminal joint of right leg securiformly dilated, and the
penultimate joint of same leg armed inside with a short spiniform process.
Remarks.—This genus was established by Claus, to include the Diaptomus
abdominalis, Lubbock, and another Mediterranean species P. gracile, Cls.; but
as the generic name proposed, Pleuwromma, had been previously appropriated in
Zoology, Dr. Giesbrecht has recently changed it to Plewromamma. This change
becomes the more necessary, as the organ regarded by Claus as an eye, has
turned out to be of a very different nature, being undoubtedly, as first suggested
by Dr. Dahl, a special luminous organ. The genus is very nearly related to
Metridia, though differing not only in the presence of the above-named organ,
but also in some other features mentioned in the above diagnosis. We know at
present of 6 species of this genus, one of which belongs to the fauna of Norway,

and will be described below.

50. Pleuromamma robusta (Dahl).
(Pl. LXXVIIT & LXXIX).

Pleuromma robustum, F. Dahl in ,Zool. Anzeiger*, Vol. 16, p. 105.

Specific Characters.— Female. Body, as compared with the other species,
somewhat robust, with the anterior division, seen dorsally, oblong oval in form,
greatest width exceeding '/; of the length, and occurring a little behind the
middle, anterior extremity somewhat contracted and triangularly produced at the

tip, posterior only slightly attenuated. Cephalosome not attaining the length of

116

the metasome, dorsal face considerably vaulted, rostral projection somewhat pro-
minent, and having in front 2 dentiform ledges. Lateral parts of last segment
of metasome obtusely rounded. Urosome slightly exceeding half the length of
the anterior division, genital segment bulging considerably below. Caudal rami
comparatively small, shorter than the anal segment, outermost seta occurring in
about the middle of the outer edge. Anterior antenne, when reflexed, reaching
beyond the middle of the 2nd caudal segment, dentiform projections of the prox-
imal joints comparatively small and not recurved. Last pair of legs distinctly
4-articulate, terminal joint lamellarly dilated and oval in form, being finely ciliated
on both edges and armed at the tip with 3 sete, the outer 2 rather short, the
innermost very slender and elongated, extending obliquely inwards.

Male much smaller than female and of more slender form, with the uro-
some perfectly symmetrical and very narrow, 2nd and 3rd segment partly hairy
outside. Left anterior antenna distinctly geniculate, and having the sensory
appendages of the proximal joints very large. Second pair of legs with the inner
ramus of same structure on both sides, and agreeing with that in the female. Last
par of legs very asymmetrical, right leg much the larger and having the terminal
joint considerably dilated, securiform, that cf left leg much narrower, oblong.

Colour not yet ascertained.

Length of adult female 4.30 mm., of male 3.50 mm.

Remarks.—This species has been briefly mentioned by Dr. F. Dahl in
the above-quoted Journal; but no detailed description or figures have as yet
been published. I think, however, that I am right in identifying the present form
with Dahl’s species, as it seems to agree pretty well with it both in size and in
some of the anatomical details mentioned by that author.

Occurrence.—Some few specimens of this handsome species were found
in a plankton-sample taken during the cruise of the “Michael Sars” in 1900, at
Stat. 9, located somewhat North of the Faroe Islands, the depth being recorded
to be from 200 to 400 metres. A single female specimen also occurred in another
plankton-sample taken during the same cruise in the Storfjord, inland from
Aalesund (Stat. 4), its occurrence here evidently proving this form to be a true
member of the Norwegian fauna.

Distribution.— Atlantic Ocean in depths from 100 to 1500 meters (Dahl),

Faroe Channel, West of Ireland (Norman’s collection) !).

1) Determined by the present author.

117

Fam. 17. Heterorhabdide.

Characters.—Body more or less depressed, and generally highly pellucid
Cephalosome well defined from the 1st pedigerous segment, front more or less
produced, and carrying below 2 delicate tentacular filaments. Last 2 segments
of metasome united. Urosome consisting in female of 3 or 4 segments, in male
of 5 segments. Caudal rami of different shape in the different genera, in some
cases asymmetrical; setee present in the normal number, Anterior antenne very
slender, in some cases of quite an extraordinary length, and composed in female
of 25 articulations; left antenna in male generally geniculate. Posterior antenne
with the rami more or less unequally developed. Oral parts, especially mandibles
and maxille, differing conspicuously in their structure from those parts in other
Calanoids. Legs with both rami triarticulate; last pair biramous and natatory,
like the preceding pairs, outer rami of this pair slightly transformed in male.
No ovisac present in female.

Remarks.—The forms belonging to this family, in the restriction here
adopted, ure chiefly characterised by the pellucid, more or less depressed body,
the very slender anterior antenne, the anomalous structure of some of the oral
parts, and finally, by the fact that the last pair of legs are biramous and nata-
tory, like the preceding pairs. In the last-named character, this family agrees
with the Centropagide; but it is otherwise very different. The family comprises
at present 3 distinct genera, viz., Heterorhabdus, Giesbr., Haloptilus, Giesbr. and
Augaptilus, Giesbr. The first 2 of these genera are represented in the fauna

of Norway, and will by treated of below.

Gen, 20. Heterorhabdus, Giesbrecht, 1898.

Syn: Heterocheta, Claus (not Westwood).

Generic Characters.—Body more or less robust, with the anterior division
somewhat vaulted above, and depressed only in its anterior part. Cephalosome
comparatively short, with a well-marked cervical depression above in the middle,
front slightly projecting in front and carrying below 2 nearly straight tentacular
appendages. Lateral parts of last segment of metasome not produced. Urosome
of moderate length, and consisting in female of 4 segments, the last of which,

however, is imperfectly defined from the caudal rami; the latter scarcely at all

divergent, and conspicuously asymmetrical, the Jeft one being the larger, and
having one of the apical sets excessively prolonged. Eye wholly wanting. An-
terior antenne greatly attenuated and abruptly curved in their proximal part;
left one in the male geniculate. Posterior antennz with the rami of not very
different length, the outer one 7-articulate. Mandibles with the cutting teeth much
reduced in number, the outermost one widely separated from the others and claw-
shaped, with a peculiar rim outside; palp well developed, with the inner ramus
shorter than the outer. Maxille with the inner ramus of the palp quite rudi-
mentary, outer ramus greatly produced, and tipped with long sete. Anterior
maxillipeds exceedingly powerful, and armed in their distal part with strong,
anteriorly-curving claw-like spines, proximal digitiform lobes rudimentary. Posterior
maxillipeds scarcely longer than the anterior ones, and much narrower, with the
2nd basal joint very slender, terminal part 5-articulate, and clothed with com-
paratively short sete. Legs powerfully developed, outer ramus in 2nd to 4th
pairs very large, with the terminal joint considerably expanded, especially in the
3rd pair, and having both the spines and the sete unusually short. Last pair
of legs in female considerably smaller than the preceding ones, outer ramus with
a slender falciform spine inside the 2nd joint; those in male somewhat larger,
with the outer rami subprehensile and without any natatory sete.
Remarks.—This genus was established in the year 1863 by Claus, to
comprise 2 Mediterranean species. As, however, the generic name, Heterocheta,
proposed by him had been previously appropriated in Zoology, Dr. Giesbrecht
has recently changed it to Heterorhabdus. It is a very distinct genus, easily
recognizable, among other things, by the peculiar asymmetry of the caudal rami,
and the excessive length of one of the apical sete issuing from the left ramus.
Dr. Giesbrecht enumerates no less than 13 species belonging to this genus, and
a 14th, H. compactus, G. O. Sars, has been added by the present author from
Nansen’s Polar Expedition. Only a single species belongs to the fauna of Nor-

way, and it will be described below.

51. Heterorhabdus norvegicus (Boeck).
(Pl LXXX & LXXXf).
Heterocheta norvegica, Boeck. Nye Slegter og Arter af Saltvandscopepoder.
Chr. Vid. Selsk. Forh. 1872, p. AO.
Specific Characters.—Kemale. Body moderately slender, with the anterior
division, seen dorsally, oval fusiform in outline, greatest width somewhat exceeding
‘/3 of the length, and occurring about in the middle, anterior extremity gradually

narrowed and obtusely truncated at the tip, with a knob-like projection in the

P19

middle of the front, posterior extremity only slightly contracted; seen laterally,
evenly vaulted above. Cephalosome about equalling in length the 3 succeeding
segments combined, and distinctly depressed in its anterior part, front somewhat
abruptly bent anteriorly, tentacular appendages very slender and extending obliquely
backwards. Lateral parts of last segment of metasome broadly rounded at the tip.
Urosome equalling about half the length of the anterior division, genital segment
fully as long as the 2 succeeding ones combined, and rather tumefied in the middle,
bulging considerably below, and having a slight dorsal depression behind; posterior
edge of this and the 2 succeeding segments finely denticulate above Anal segment
not widening at all distally, and on left side wholly confluent with the correspon-
ding caudal ramus, on right side only faintly defined. Left caudal ramus much
larger than right, both slightly attenuated, being cut off very obliquely at the end
in such a manner that only 2 of the marginal set issue from the tip, the other
3 from the outer edge; outer apical seta of left ramus excessively prolonged, even
exceeding the whole body in length, and terminating in a very slender, hair-like
point. Anterior antenne about the length of the body, and having the Ist joint |
rather large and compressed, equalling in length the 5 succeeding joints com-
bined, distal part very slender and generally extended directly laterally. Anterior
maxillipeds with the distal claws very strong, though not nearly attaining the
length of the stem. Posterior maxillipeds with a remarkably prolonged, subsigmoid
spine issuing from the middle of the 1st basal joint anteriorly. Inner ramus of
3rd pair of legs not attaining even '/; of the length of the outer. Last pair of
legs with the outer ramus about twice the length of the inner, falciform spine
shorter than the terminal joint and extending almost straight inwards.

Male somewhat more slender than female, with the urosome very narrow.
Left anterior antenna with the middle section but slightly tumefied, terminal
section very slender, and 4-articulate. Last pair of legs somewhat asymmetrical,
right leg with a large and abruptly curved, sausage-shaped prominence inside the
2nd basal joint, outer ramus rather strongly built, with the Ist joint remarkably
produced at the end outside, 2nd joint oval in form, with an irregular protuber-
ance inside, terminal joint but slightly exceeding in length the 2 preceding ones
combined, the apical part being quite short; outer ramus of left leg of about
same length as that of the right, terminal joint lamellar and produced at the tip
to a slender, somewhat flexuous spine of moderate length.

Colour.—Body highly pellucid, with a faint yellowish tinge, cand exhibiting
within the anterior division a number of clear globular oil-bubbles.

Length of adult female reaching to 4.20 mm, that of male about

the same.

120

Remarks.—This form was briefly mentioned by Boeck in the above-
mentioned paper, and some figures of it were given by the present author in his
account of the Crustacea procured during Nansen’s Polar Expedition. It is nearly
allied to the 2 Mediterranean species, A. spimifrons and H. papillatus, recorded
by Claus; but it is of larger size than either of them, and moreover differs in
the relative length of the anterior antenne, and in the structure of the last pair
of legs in the male.

Occurrence.—Boeck first found this form at Haugesund, west coast of
Norway. I have myself taken it in several places, from the Christiania Fjord
and as far north as the Lofoten Islands, but only in greater depths, of more than
150 fathoms. It also occurred not unfrequently in some plankton-samples taken
from deep water in the open sea during the cruise of the “Michael Sars” in 1900.

Distribution.—Polar basin crossed by Nansen, in several places rather

abundantly (the present author), Greenland, Faroe Channel (Norman’s collection).

Gen. 21. Haloptilus, Giesbrecht, 1898.

Syn: Hemicalanus, Claus (not Dana).

Generic Characters.—Body subdepressed and _ highly pellucid. Cephalo-
some comparatively large; more or less produced in front, and without any
distinct cervical depression; rostral filaments slender and recurved. Lateral parts
of last segment of metasome not expanded. Urosome comparatively short, com-
posed in female of 4, in male of 5 segments. Caudal rami perfectly symmetrical,
not much produced, and somewhat divergent, setee normally developed, and richly
plumous. Eye wholly absent. Anterior antennz very slender and narrow, with
some of the bristles much elongated; left antenna in male geniculate. Posterior
antenne with the inner ramus greatly produced, outer ramus comparatively small.
Mandibles with the masticatory part very narrow and bifurcate at the tip, palp
slender, with the inner ramus much longer than the outer. Maxille with the
inner ramus of the palp small, but distinct, outer ramus considerably produced,
and carrying at the tip long plumous sete. Anterior maxillipeds of moderate
size, with all the lobes distinctly developed, distal sete not claw-like. Posterior
maxilliipeds much larger than the anterior, terminal part 5-articulate and clothed
with long, auteriorly-curving sete. Legs not very powerful, outer ramus of 2nd

to 4th pairs of moderate size, with the terminal joint far less expanded than in

Copepoda

Calanoida.

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Temora longicornis (Mull)

6.0. Sars auto gr.

Copepoda

Temonida Calanorda, Pow

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SED PSLy
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SYS SS

6.0. Sars auto gr. Tryktiden private Opmaaling, Chr

—Temora longicornis (Mull.)
(continued)

Copepoda

Temorida Calanorda. PL. LXVII

sn ae

Saini

G.G. Sars autogp. Tryktiden private Opmaaling, Chra

Eurytemora velox ( Lilljeborg,)

2 ORT EI AA TS NN SE LA RT AON ARE NR PERN PE

PI. LXV

pepoda
fanorda.

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‘Trykt iden private Opmaaling,Chra

(Liljeborg

(continued)

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6.0.Sars autogr.

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Eurytemora hirundoides, Nordpvist

6.0.Sars autogr.

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Tryktiden private Opmaaling, Chra

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pepoda
Calanorda.

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CRG

Tryktiden private Opmaaling, Chra.

6.0. Sars auto gr.

saliens (Lilljeb.)

Heterocope

Copepoda

Temornide Calanoida. Pie Te

NS

6.0. Sars autogr. Trykt iden private Opmaaling,Chra.

Heterocope saliens (Lilljeb.
(continued).

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PY. LXXI

epoda

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Temorida.

Tryktiden private Opmaaling,Chra

6.0. Sars autogr

borealis (Fischer)

Heterocope

PI. LXXIV

Tryktiden private Opmaaling,Chra

pepoda
Calanoida.

Co

6.0. Sars autogr.

Temorida.

Heterocope appendiculata, G.0.Sars

pepoda
Calanorda.

Co

Metridiida.

VY WARS. a Ss Se

SSS

ay

Tryktiden private Opmaaling, Chra

longa (Lubbock)

Metridia

6.0. Sars autogr

pepoda

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Metridiida.

Calanoida.

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Metridia

6.0. Sars autogr.

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PL. EXXVII

Copepoda
Calanorda.

Metridiida.

Tryktiden private Opmaaling,Chra.

6.0. Sars autogr.

lucens, Boek.

Metridia

PL UXXVI

pepoda
Calanoida.

Ore
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Metridiida.

CMG AM LY AM he ff

LY

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poe

4 APES

Tryktiden private Opmaaling,Chra

(Dahl)

robusta

Pleuromamma

6.0. Sars auto gr.

Copepoda
PI. LXXTX.

Metridida.

Calanorda.

Tryktiden private Opmaaling,Chra.

(Dahl)

robusta

Plauromamma

6.0.Sars autogr.

- (continued)

Copepoda
Calamorda.

Heterorhabdida.

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Tryktiden private Opmaaling,Chra

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SRUSTAGE

NORWAY -

Be es WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

Pe G. O..SARS

: 4 ei VOL. IV

oe COPEPODA
ate i CALANOIDA

PART XE & XIL

HETERORHABDIDA: (continued), ARIETELLIDA, PSEUDO-
-CYCLOPIDA, CANDACUDA!, PONTELLID ©

WITH 16 AUTOGRAPHIO PLATES

ace BERGEN

> = PUBLISHED BY THE BERGEN MUSEUM
pes os SOLD BY

| " ALB. CAMMERMEYER’S FORLAG, CHRISTIANIA
1902 -

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Heterorhabdus, apical spine slender, setiform. Last pair of legs in female resem-
bling in structure the preceding pairs, but of inferior size, 2nd joint of outer
ramus without any falciform spine inside; those in male with the outer rami
imperfectly prehensile.

Remarks.—This genus was established by Claus in the year 1863, to
comprise some Mediterranean Calanoids distinguished by the extraordinary pellu-
cidity of the body, and the richly plumose sete with which some of the appendages
were ornamented. The generic name proposed, Hemicalanus, had however previ-
ously been used by Dana in a different sense, and for this reason it has recently
been replaced by Dr. Giesbrecht with that of Haloptilus. Two of the species
described by Claus as belonging to this genus have moreover been transferred
by the same author to another nearly-related genus, Awgaptilus, Giesbr. In the
restriction now generally adopted, the present genus is easily recognized by
the perfectly hyaline, sub-depressed body, tlie comparatively short urosome, the
exceedingly slender anterior antennz, and the greatly produced inner ramus of
the posterior ones. Moreover the structure of the oral parts is rather charac-
teristic. We know at present of 11 or 12 species belonging to this genus. They
are, on the whole, southern in distribution, 6 of the species occurring in the
Mediterranean, the others in the Pacific and the tropical part of the Atlantic Ocean.
‘wo of the species, however, have been stated to occur occasionally in the Nor-
wegian Sea, one of them even as far north as in the Polar basin crossed by Nansen.
These 2 species, which can thus only be regarded as quite exceptional visitors

in the northern ocean, will be described below.

52. Haloptilus longicornis (Claus).
(Pl. LXXXI & LXXXIII, fic. 1).

Hemicalanus longicornis, Claus. Die freilebenden Copepoden, p. 179, Pl. XXIX, fig. 1.

Specific Characters.— Female. Body rather slender and distinctly depressed,
with the anterior division, seen dorsally, oblong fusiform in outline, greatest width
scarcely exceeding '/; of the length, and occurring about in the middle, anterior
extremity somewhat contracted, though slightly widening at the insertion of the
anterior antennee, and projecting in the middle to a knob-like prominence, posterior
extremity considerably narrowed. Cephalosome about the length of the metasome
and genital segment taken together, rostral prominence obtuse, and occurring not
far from the frontal edge; tentacular filaments very delicate. Last segment of

metasome with the lateral parts not at all expanded, Urosome scarcely exceeding

17 — Crustacea.

122

'/; of the length of the anterior division, genital segment somewhat dilated in
its anterior part, and about the length of the 3 succeeding segments combined.
Caudal rami of moderate size and slightly divergent, sete not very different in
length, and densely plumose, the outermost one issuing from a separate ledge of
the outer edge, the others from the transversely truncated tip. Anterior antenne
of quite extraordinary length, being more than twice as long as the whole
body, and very slender, with some of the bristles greatly elongated and extending
in different directions. Posterior antenne with the inner ramus greatly produced
and very slender, outer ramus scarcely more than '/; as long, and composed of
7 articulations. Legs of 2nd to 4th pairs with the inner ramus scarcely half as
long as the outer, terminal joint of the latter about as long as the other 2 com-
bined, and somewhat narrowed distally. Last pair of legs with a slender seta
issuing from the outer corner of the 2nd basal joint.

Colour. Body highly pellucid, and almost perfectly hyaline. Length of
adult female 2.15 mm.

Remarks.—This form, first described by Claus from the Mediterranean,
is easily recognizable from the other species of this genus by the excessively
elongated anterior antennw, and by the slight, knob-like projection of the front.
It is also rather inferior in size to most of the other species.

Occurrence.—A solitary, but well-preserved female specimen of this form
was found in a plankton-sample taken during the cruise of the “Michael Sars”
in 1901, at Stat. 25 a, located between Finmark and Bear Island.

Distribution.—Mediterranean (Claus), Atlantic and Pacific Oceans between
26° N. and 40° S. Lat. (Giesbrecht), gulf of Guinea (Scott).

53. Haloptilus acutifrons, Giesbr.
(Pl. L XXXII, fig. 2).
Hemicalanus acutifrons, Giesbrecht, Pelagische Copepoden. Fauna d. golf. Neapel, p. 384, Pl. 3,
fig. 11, Pl. 27, fic. 12, Pl. 42, figs. 12, 20.

Syn: Hemicalanus spinifrons, G. O. Sars.

Specific Characters.—Female. Anterior division of body, seen dorsally,
narrow oblong in form, greatest width only slightly exceeding '/, of the length,
and occurring somewhat in front of the middle, anterior extremity produced to a
long spiniform projection pointing straight anteriorly, posterior gradually narrowed.
Cephalosome occupying more than half the length of the body, rostral prominence
very slight and somewhat remote from the frontal edge, tentacular filaments rather

slender. Urosome very short and somewhat thicker than in H. longicornis, other-

123

wise of a very similar structure. Anterior antennee shorter than in that species,
reaching, when reflexed, beyond the caudal rami by about the 5 outer joints.
Posterior antenne with the inner ramus about twice the length of the outer.
Oral parts and legs nearly as in the preceding species.

Colowr. Body perfectly hyaline.

Length of adult female 3.20 mm.

Remarks.—1 am now of opinion that the specimen described from Nan-
sen’s Polar Expedition as Hemicalanus spinifrons is more properly referable to
the above-named Mediterranean species, with which it seems to agree fairly well,
except in its size, which is somewhat larger. Another specimen, exactly agreeing
with that found in the Polar Sea, has subsequently been captured farther south,
in the Norwegian Sea, for which reason the species is now included in the Fauna
of Norway. It may be at once distinguished from H. longicornis by the spiniform
projection of the front, and the far less elongated anterior antenne.

Occurrence.—The above-described specimen was found in a_plankton-
sample taken during the cruise of the “Michael Sars” in 1900 at Stat. 34, located
between Jan Mayen and the Norwegian coast, the depth being recorded to be
from 500 to 1000 metres.

Distribution.—Mediterranean (Giesbrecht).

Fam. 18. Arietellide.

Characters.—Body comparatively robust, not depressed. Cephalosome,
as a rule, well defined from the Ist pedigerous segment, front more or less
produced below and carrying 2 tentacular appendages. Last 2 segments of
metasome united. Urosome comparatively short, composed in female of 4, in
male of 5 segments. Caudal rami well defined, short, with some of the apical
setee much elongated. Anterior antennz less slender than in the Heterorhabdide,
in some cases very short, number of articulations considerably reduced, left
antenna, as a rule, longer than the right, and in male imperfectly geniculate,
with the terminal part very short, biarticulate. Posterior antennee with the inner
ramus longer than the outer, and having a limited number of set at the tip.
Oral parts somewhat resembling in structure those in the Heterorhabdide; mandi-

bular palp, however, without any trace of an inner ramus, and posterior maxil-

eee

lipeds more robust, with the terminal part reflexed. The 4 anterior pairs of legs
comparatively short and compact, with both rami triarticulate and less unequal
than in the Heterorhabdide. Last pair of legs not natatory in either of the sexes,
inner ramus rudimentary or quite wanting.

Remarks.—The type of this new family is the genus Arietellus of Gies-
brecht, which was referred by that author to his subfamily Heterochetine,
though in some respects, and more especially in the structure of the last pair of
legs, it differs very materially from the 3 genera now included in the family
Heterorhabdide. On the other hand, it exhibits a close relationship to the genus
Paramisophria of Scott, as also to another new genus, Scottula, to be described
below, these 3 genera accordingly forming together a natural group or family.
The chief distinctive character of this family, as compared with the Heterorhabdide,
is the very different structure of the last pair of legs, these in the latter family being
natatory like the preceding ones, whereas in the present family they are much
reduced in size, and not at all natatory in either of the sexes. This is appar-
ently a character of fundamental importance, and has for this reason been taken
into consideration in the distinction of several other Calanoid families. Another
peculiar feature characteristic of the present family, is the mequality of the
anterior antenne in both sexes, the left one being the longer. This inequality
is especially conspicuous in the genus Scottula, and is also present, though in a
less conspicuous manner, in the genus Paramisophria. In the typical genus
Arietellus, it is true, no mention of such an inequality has been made; but,
taking into consideration the near relationship of this genus to Paramisophria,
it seems to me very probable that this character has been overlooked, as it
actually was previously in the case of Paranuisophria. Of the 3 genera at present
comprised within the family Avvetellidw, 2 are represented in the fauna of Norway,

and will be treated of below.

Gen. 22. Seottula, G. O. Sars, n.

Generic Characters.—Body quite calanoid in appearance, with the anterior
division moderately tumefied; front considerably produced below, and carrying 2
straight tentacular appendages. Last segment of metasome simple, without any
subdorsal projections. Urosome moderately slender, with the genital segment in

female comparatively short. Caudal rami with 3 of the sete much elongated,

outermost seta quite rudimentary. Hye wholly absent. Anterior antenne of
moderate length, and very unequal in both sexes, the left one being much the
longer; both antennze in male with long, band-like sensory appendages on the
proximal part. Posterior antenne with the inner ramus very slender, outer
6-articulate, with the terminal joint comparatively short. Mandibles very strong,
with only 4 cutting teeth, the outermost claw-like, palp with the ramus shorter
than the basal part. Maxille with the masticatory lobe poorly developed and
armed with only 2 spines, inner ramus of palp altogether wanting, outer large,
sub-sigmoid, with 3 long curved sete at the tip. Both pairs of maxillipeds power-
fully developed, the anterior ones with the last joint of the basal part dilated in
the middle, and carrying anteriorly a comparatively short but strong spine,
appendages of the terminal part slender, claw-like. Posterior maxillipeds with
the terminal part 5-articulate, and armed with strong claw-like spines finely den-
ticulated on both edges. Natatory legs moderately strong, basal part not pro-
duced at the end inside, 2nd joint of inner ramus normal. Last pair of legs in
female rather small, 3-articulate, 2nd joint not produced inside, terminal joint of
moderate size and tipped with an ordinary seta; those in male 5-articulate and
but slightly asymmetrical, terminal jot on both legs transformed to a slender claw.

Remarks.—This new genus is undoubtedly nearly allied to Arietellus of
Giesbrecht, differing, however, not only in the very conspicuous inequality of the
anterior antenn, but also in the structure of the last pair of legs and that of
the caudal rami. I have much pleasure in naming this genus in honour of the
distinguished Scottish naturalist, Th. Scott, who has done so much important work
in this order. A genus of Ostracoda, Scottia, has already, as is well known, been
established by Canon Norman, likewise in honour of this naturalist. The present

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

54. Seottula inseqvicornis, G. O. Sars, n. sp.
(PIE IXOXeXSEV ok IPXONOXEV)

Specific Characters—Female. Anterior division of body but slightly
vaulted above, seen dorsally, regularly elliptical in form, greatest width equalling
about half the length and occurring in the middle, both extremities gradually
tapered, the anterior one narrowly rounded, the posterior deeply emarginated in
the middle. Cephalosome well defined from the Ist pedigerous segment, rostral
prominence rather large, conical, and pointing straight downwards, tentacular

appendages slender and elongated. Lateral lobes of last segment of metasome

126

somewhat produced and narrowly rounded at the tip. Urosome exceeding in
length */; of the anterior division, genital segment scarcely protuberant below.
Caudal rami scarcely twice as long as they are broad, and not at all divergent,
outermost seta present only as a minute hair, outermost but one only slightly longer
than the caudal rami, the other 3 very much elongated. Left anterior antenna
about the length of the anterior division of the body, and composed of 20 articu-
lations, 7th to 10th very small; right antenna much shorter, scarcely reaching,
when reflexed, beyond the 1st pedigerous segment, and composed of 19 arti-
culations only, bristles on both antenne partly ciliated. Posterior antennz with
the distal joint of the inner ramus shorter than the proximal one. Last pair of
legs with the 2nd joint provided at the end inside with a long seta, terminal
joint about the length of the other 2 combined, and armed outside with 2 short
spines.

Male resembling the female in shape, but of considerably smaller size,
and, as usual, having the urosome narrower and 5-articulate. Anterior antennz
exhibiting a similar inequality in Jength to that in the female, both provided on
the proximal part with long band-like sensory appendages curved backwards, left
one with an imperfect hinge near the tip, middle section scarcely at all tume-
fied. Right last leg a little longer than left, but otherwise of a very similar
structure.

Colour. Body rather pellucid, with a light yellowish grey tinge.

Length of adult female 1.10 mm., of male 0.86 mm.

Remarks.—As mentioned above, this is as yet the only known species of
the present genus. It is easily recognizable from all our other Calanoids by the
very conspicuous inequality of the anterior antenne. Its appearance is otherwise
quite calanoid.

Occurrence.—Some few specimens of this peculiar Calanoid, all of the
female sex, were found many years ago by the present author in the upper part
of the Christiania Fjord, not far from the town, the depth being about 30 fathoms.
A solitary male specimen, the one figured here, was further captured last summer
in another locality of the Norwegian coast, viz., in the Storfjord, inland from
Aalesund, at a depth of about 60 fathoms. It is a true bottom-form, always
keeping close to the ground, and accordingly can only be procured by the aid
of the dredge. This circumstance, in addition to its small size and insignificant
colouring, may be the cause of its having escaped the attention of other authors,
even that of the sharp-sighted Scottish naturalist, Th. Scott.

Gen. 23. Paramisophria, Scott, 1897.

Generic Characters.—Body cyclopoid in appearance, with the anterior
division considerably tumefied. Cephalosome only faintly defined from the Ist
pedigerous segment, front produced below to a very small rostral prominence,
carrying on the tip 2 extremely minute filaments. Last segment of metasome
with 2 very conspicuous subdorsal projections. Urosome somewhat robust, with
the genital segment in female comparatively short. Caudal rami rather broad,
with all the sete well developed, 2 of them considerably longer than the others.
Eye inconspicuous. Anterior antenne very short and less unequal than in Scot-
tula, both consisting in female of 21 articulations; left antenna in male with a
slight hinge near the tip. Posterior antenne and oral parts resembling in structure
those in Scottula; maxille, however, with the masticatory lobe more fully deve-
loped, and with a distinct, though small mner ramus on the palp. Maxillipeds
less robust. Natatory legs powerfully developed, with the rami considerably
broader than in Scottula, basal part in 2nd to 4th pairs produced at the end
inside to an acute triangular projection, 2nd joint of inner ramus considerably
expanded outside. Last pair of legs of larger size than in Scottula, being in
female 3-articulate, with the 2nd joint produced inside to a narrow lobe, terminal
joint of considerable size and coarsely spinous outside; those in male 5-articulate,
without any lobe inside the 2nd joint, terminal joint in right leg unguiform, in
left spatulate.

Remarks.—This genus was established by Th. Scott in the year 1897,
to include a peculiar deep-water Calanoid found by him off the Scottish coast.
The name Paranisophria is somewhat inappropriate, as this genus in reality does
not exhibit any very close relationship to Misophria, which even, as shown by
Dr. Giesbrecht, belongs to quite a different division of the Copepoda, viz., the
Cyclopoida. It cannot of course be placed in the family Misophriida, as first
suggested by Th. Scott, whereas it is unquestionably closely related to the genus
Arietellus of Giesbrecht, and accordingly ought to be included in the family
Arietellidw, as here defined. It differs conspicuously from Scottula, to which
it bears a close relationship in some of the anatomical details, in the ge-
neral appearance of the body, the much shorter and less unequal anterior
antennee, the full number of caudal sets, and the larger size of the last pair of

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

ees

55. Paramisophria Cluthe, Scott.
(Pl. LXXXVI & LXXXVII).

Paramisophria Cluthe, Scott. The Marine Fishes and Invertebrates of
Loch Fyne; 15th Annual Report of the Fisheries Board for Scotland, p. 147,
PI. di; figs: 3—8, Pl; Til, tgs. 13—16.

Specific Characters—Female. Body rather short and compact, with the
anterior division, seen dorsally, oval in form, greatest width equalling about half
the length, and occurring somewhat behind the middle, anterior extremity gradu-
ally narrowed and obtusely rounded at the tip, posterior only slightly contracted.
Cephalosome considerably vaulted, with the dorsal margin forming quite an even
curve as far as the tip of the very small rostral prominence. Last segment of
metasome with the subdorsal processes spiniform and pointing straight backwards,
lateral lobes broadly rounded, with a small indentation in the middle. Urosome
scarcely exceeding '/; of the length of the anterior division, genital segment
shorter than the 2 succeeding segments combined, anal segment rather small.
Caudal rami about twice the length of the anal segment, and somewhat flattened,
all the 5 marginal sete richly plumose, the innermost but one the longest.
Length of anterior antenne scarcely exceeding that of cephalosome, the left one
slightly longer than the right, bristles of the anterior edges in both antenne
partly ciliated. Posterior antenne with the distal joint of the inner ramus about
the length of the proximal one. Last pair of legs with the inner projection of
2nd joint comparatively small, and cylindric in form, carrying at the tip a small
denticle and a slender plumose seta; terminal joint fully twice as long as the
other 2 combined, and armed with 6 strong spines, 4 of which issue from the
outer edge, and 2 from the tip. inner edge straight and perfectly smooth.

Male resembling the female, but somewhat less robust, and with the
urosome narrower and 5-articulate. Left anterior antenna with the middle
section slightly tumefied, terminal section comparatively short and imper-
fectly biarticulate. Last pair of legs only slightly asymmetrical, penultimate
joint in both legs lamellarly expanded, with a single spine outside, terminal joint
of right leg transformed to a slender claw carrying 2 small spines outside the
base, that of left leg spatulate, with 3 short spines at the end.

Colour not yet ascertained. Length of adult female !.20 mm., of male
1.10 mm.

Remarks.—This form was first described by Th. Scott from some female

specimens found in dredged material from Loch Fyne, Scotland. In its external

129

appearance it differs considerably from the ordinary Calanoid type, resembling
rather, in this respect, the Cyclopoida, which may have been Th. Scott’s reason
for placing it in the family Misophrude.

Occurrence. Only 2 or 3 specimens of this remarkable form have hitherto
come under my notice. They were taken many years ago at Christiansund, west
coast of Norway, the exact depth not being recorded. On a closer examination,
one of the specimens turned out to be an adult male, though at first I did not
recognise it as such, on account of the inconspicuous sexual characters.

Distribution.—Scottish coast (Th. Scott).

Fam. 19. Pseudocyclopide.

Characters.—Body quite cyclopoid in appearance, though, as in other
Calanoids, having the last segment of metasome firmly connected with the preceding
one. Cephalosome well defined from the Ist pedigerous segment, front acutely
produced below, and without any tentacular appendages. Urosome consisting in
female of 4, in male of 5 segments. Anterior antennze very short, with the
number of articulations reduced; right antenna in male distinctly geniculate.
Posterior antenne with both rami well developed. Oral parts on the whole built
upon the calanoid type. Legs robust, cyclopoid in shape, with both rami 3-arti-
culate; last pair im female resembling in structure the preceding pairs, in male
much transformed, prehensile.

Remarks.—TVhis family has been established by Dr. Giesbrecht, to include
the genus Pseudocyclops of Brady, which was erroneously placed by the latter
author in the family Misophriide. Among the more prominent characters dis-
tinguishing this family, may be named the structure of the last pair of legs,
these being biramous and natatory in the female, whereas in the male they are
transformed to very large and compact prehensile organs, somewhat recalling the
copulative appendages in the Ostracoda. We only know at present of a single

genus belonging to this family.

18 — Crustacea. : ,

130

Gen. 24. PSeudocyelops, Brady, 1872.

Generic Characters —Body short and compact, with the anterior division
considerably tumefied. Cephalosome strongly vaulted, and projecting below in a
sharply pointed rostrum, which in the male is movably connected with the head.
Last segment of metasome rather small, but distinctly defined from the preceding
one. Urosome with the anal segment very small. Caudal rami short, with the
outermost seta spiniform. Eye distinctly developed. Anterior antenne scarcely
longer than the cephalosome, and composed of 15 to 18 articulations; right
antenna in male distinctly geniculate, with the terminal part 4-articulate. Posterior
antenne somewhat cyclopoid in shape, the distal joint of the inner ramus being
connected with the proximal one at nearly a right angle, outer ramus about same
length as the inner, and only 3-articulate. Mandibles with the palp distinctly
biramous. Maxille with the inner ramus of the palp considerably produced.
Anterior maxillipeds rather compact, with all the digitiform lobes distinct, appen-
dages of terminal part comparatively small, setiform. Posterior maxillipeds
scarcely longer than the anterior and somewhat resembling those in the genus
Eurytemora. The 4 anterior pairs of legs rather powerful, with strong spines
outside the outer ramus. Last pair of legs in female with the natatory sete
much reduced in size, inner ramus short, biarticulate or triarticulate; those in
male somewhat asymmetrical, right leg the larger and hooked at the tip, inner
ramus lamellar.

Remarks. This genus, as stated above, was placed by its founder, Prof.
Brady, in the family Misophriide, apparently on account of some resemblance in
its external appearance to the genus Misophria. As subsequently shown by Dr.
Giesbrecht, it 1s however very different, not even belonging to the same division ;
and, as it also differs considerably from the other true Callanoids, its rank as
the type of a distinct family is fully justified. It is only to be regretted, that
the name of another Calanoid family, Psewdocyclopiide, founded on the genus
Pseudocyclopia of Scott, is so very like that of the present family. We know
at present of 3 species of this genus, one from the Bay of Naples, and 2 from
the Scottish coast. One of the latter is also found off the Norwegian coast, and

will be described below.

131

56. Pseudocyclops obtusatus, Brady.
(Pl, WxeXRCVIEL),
Pseudocyclops obtusatus, Brady & Robertson, in Ann. Nat. Hist. ser. IV, Vol. XI, p. 128.
Pl. VIM, figs. 4—7.

Specific Characters.—Female. Anterior division of body, seen dorsally,
oval in form, greatest width slightly exceeding half the length, and occurring in
the middle, anterior extremity evenly rounded, posterior somewhat contracted ;
seen laterally, considerably vaulted above. Cepbalosome occupying nearly half
the anterior division, dorsal margin forming an even curve as far as the tip of
the rostrum; the latter rather strong, slightly curved, and terminating ima sharp
point. Last segment of metasome very small, with the lateral lobes narrowly
rounded. Urosome comparatively short, scarcely exceeding '/; of the length of
the anterior division, anal segment almost obsolete. Caudal rami scarcely longer
than they are broad, innermost but one of the apical sets: much longer than the
others. Eye rather large, subdorsal. Anterior antennze, when reflexed, scarcely
reaching beyond the cephalosome, and consisting of 18 articulations, bristles
partly ciliated. Posterior antennz with the distal joint of the inner ramus fully
as long as the proximal one. Last pair of legs with the inner ramus distinctly
3-articulate; terminal joint of outer ramus with 4 natatory sete inside.

Male somewhat smaller than female, and having the rostral projection
sharply defined at the base. Urosome much more slender than in female, with
some of the segments slightly produced dorsally. Right anterior antenna with
the middle section somewhat tumefied. Last pair of legs very massive, basal
part of both legs considerably tumefied, and on right side biarticulate, on left
uniarticulate; outer ramus with a strong deflexed spine outside, and terminating
on the right leg in 2 slender juxtaposed claws, on left leg in a peculiarly con-
torted, incurved piece; inner ramus on both legs lamellar.

Colour.—Body pellucid, whitish, with a slight rosy tinge along the ven-
tral face.

Length of adult female 0.80 mm., of male 0.70 mm.

Remarks.—This form was first recorded by Brady and Robertson in the
above-mentioned journal, and was subsequently re-described by the first-named author
in his well-known Monograph of the British Copepoda. The specific name obtu-
satus seems to refer to the obtusely rounded frontal part. The rostrum is also
said to be short and blunt, and is so represented in the figure of the male given;
but this may be due to the fact of the rostral plate having accidentally been

detached in the specimen examined.

132

Occurrence.—Only 3 specimens, one female and 2 males, have hitherto
come under my notice. They were taken many years ago at Christiansund, from
a depth of about 30 fathoms.

Distribution.—Scottish coast (Brady).

Fam. 20. Candaciide.

Characters.—Body quite calanoid in appearance. Cephalosome well de-
fined from the Ist pedigerous segment, front abruptly deflexed, but without any
distinct rostrum or tentacular appendages. Last segment of metasomie confluent
with the preceding one, and having the lateral parts expanded in both sexes.
Urosome consisting in female of 3, in male of 5 segments. Caudal rami com-
paratively short, with the full number of sete. Anterior antenne slender and
attenuated, with the number of articulations less reduced than in the 2 preceding
families; right antenna in male geniculate. Posterior antenne with the inner
ramus imperfectly defined from the basal part, outer ramus comparatively small,
with the terminal joints very short. Oral parts, especially the maxille, rather
different in their structure from those in other Calanoids. Anterior maxillipeds
much larger than the posterior. The 4 anterior pairs of legs with the inner
ramus consisting of only 2 joints. Last pair of legs comparatively small and of
simple structure, not natatory; those in male rather asymmetrical. No ovisac
present in female.

Remarks.—This family was established by Dr. Giesbrecht, to include
the genus Candacia of Dana, which differs considerably in some respects from
the Calanoids treated of in the preceding pages, and forms, as it were, a trans-
ition to the Pontellide. We do not know at present of more than this one
genus; but if is not improbable that in future it will be found convenient to
divide it into 2 nearly-allied genera, as at any rate the structure of the last

par of legs in the male presents 2 very different types.

Ro

Gen. 25. Candacia, Dana, 1846.

Syn: Candace, Dana.

" Iphionyx, Kroyer.

Generic Characters —Body generally rather robust, with the anterior
division more or less vaulted above, front narrowly truncate, with 2 juxtaposed
knob-like prominences below. Lateral corners of last segment of metasome more
or less produced, and, as a rule, asymmetrical in the male. Urosome of moderate
size, sometimes conspicuously asymmetrical in female; Ist segment in male with
a projection on right side. Caudal rami comparatively small, sets subequal.
Eye present or wanting. Anterior antennee consisting in female of 23 or 24
articulations, the proximal ones somewhat irregular and partly dentate in front;
right antenna in male distinctly geniculate, with the terminal section very slender,
5-articulate. Posterior antenne with the outer ramus much smaller than the
inner and 5-articulate, 2nd joimt much the largest. Mandibles with the mastica-
tory part very narrow and bifurcate at the tip, palp well developed, with the
basal part rather broad. Maxille with the proximal appendicular lobe exces-
sively prolonged, rod-hke, and carrying 3 unequal, incurved spines at the tip,
inner ramus of palp bent abruptly outwards, and having one of the apical sete
excessively prolonged, outer ramus wanting. Anterior mavxillipeds exceedingly
large and powerful, being armed distally with a restricted number of very strong
falciform claws, digitiform lobes rudimentary. Posterior maxillipeds much reduced
in size, though of normal structure. Natatory legs with the rami very unequal,
the outer one much the larger and finely serrate along the exterior edge. terminal
joint occupying more than half the length of the ramus, and armed outside with
3 comparatively small spines. Last pair of legs in female very small, 3 articulate,
in male somewhat larger, left leg 4-articulate, right 3-articulate and terminating
in some species with an imperfect chela, in others with a slender deflexed, cili-
ated seta.

Remarks.—This genus was established by Dana as early as the year
1846. The name Candacia originally proposed was subsequently changed by
the same author to Candace, and the latter name has been generally used by
subsequent carcinologists. Dr. Giesbrecht, however, in his recent synopsis, has
restored the original name Candacia, and accordingly the name of the family
must be changed from Candacide to Candaciide. The genus Iphionyx of Kroyer
it unquestionably identical with Dana’s genus. We know at present of a con-

siderable number of species belonging to this genus, amounting to about 16 in

134

all. Two of these have been found off the coast of Norway, and will be described
below. A 3rd Norwegian species, CU. elongata, has been recorded by Boeck; but
it is impossible to recognise this form, which in all probability does not belong
to the genus Candacia at all, as the lateral parts of the last segment of the
metasome are said to be rounded off, a character not found in any of the other

known species.

57. Candacia norvegica, Boeck.

(Pl. LXXXIX & XC).
Candace norvegica, Boeck. Oversigt over de ved Norges Kyster iagttagne Copepoder.
Chr. Vid. Selsk. Forh. 1864, p. 235.

Specific Characters.—Female. Body, as compared with that in the other
species, rather slender, with the anterior division, seen dorsally, oblong in form,
greatest width but slightly exceeding '/; of the length, anterior extremity con-
siderably contracted, and transversely truncated at the tip, posterior scarcely at
all attenuated, and only very slightly emarginated in the middle. Cephalosome
occupying more than half the length of the anterior division, rostral prominence
very small, bi-tuberculate. Lateral parts of last segment of metasome terminating
in a short somewhat outwards-pointing corner, acute at the tip. Urosome per-
fectly symmetrical, and equalling about '/; of the length of the anterior division,
genital segment slightly tumefied in its anterior part, and armed on each side
with a small posteriorly-pointing spine. Caudal rami shorter than the preceding
segment, all 5 sete of about same length, the outermost issuing from a separate
ledge of the outer edge. Kye wholly absent. Anterior antenne very slender and
elongated, reaching, when reflexed, beyond the tip of the caudal rami, and com-
posed of 24 articulations. Anterior maxillipeds exceedingly large, with the claw-
like spines unusually strong. Apical spine of outer ramus in the 2nd to 4th
pairs of legs exceeding half the length of the terminal joint. Last pair of legs
very small, terminal joint scarcely longer than the other 2 combined, and pro-
jecting at the tip in 2 unequal spines; outer edge armed with 2 or 3 small
denticles, inner with 3 short sete.

Male still more slender than female, with the right corner of last seg-
ment of metasome produced to a highly chitinised, dark-coloured, somewhat
incurved projection, left corner about as in the female. Genital segment with
the projection on right side rather large and irregularly tubercular at the tip.
Right anterior antenna with the middle section only slightly tumefied, and having

at the end anteriorly a finely serrate lamella. Right last leg terminating in a
pair of obtuse scissors formed by the last 2 joints.

Colour. Body in both sexes highly pellucid and almost colourless.

Length of adult female 3.20 mm., of male about the same.

Remarks.—This form was briefly mentioned by Boeck in the above-mentioned
journal; but no figures or detailed description have as yet been given, for which
reason it is placed by Dr. Giesbrecht, in his recent synopsis, among the doubtful
species of the genus. Boeck considers it to be most nearly allied to C. bispinosa
of Claus, probably on account of the similar armature of the genital segment in
the female. It is evidently much more closely related, however, to another species
described by the same author, viz., C. longimana, though it also differs from this
species in some characters, e. g. in the total absence of eye, the much more
elongated anterior antenne, and the somewhat different structure of the last pair
of legs, especially in the female.

Occurrence.—Boeck first recorded this form from the Hardanger Fjord.
I have myself found it occasionally in the following localities: at Hanko, lower
part of the Christiania Fjord, at Jelso, upper part of the Stavanger Fjord, at
Kalvaag, west coast of Norway, and at Skraaven, Lofoten Islands, in all these
places only from depths of more than 150 fathoms. The same form has also
been found by Mr. Nordgaard in the neighbourhood of Bergen, and a male spe-
cimen was sent to me by Prof. Cleve, who found it in a plankton-sample taken
from great depth in the Skagerak. This species has not yet been recorded,

however, elsewhere than from the Norwegian Sea

58. Candacia armata, Boeck.
(Pl. XCI).
Candace armata, Boeck. Nye Sleeter og Arter af Saltvands-Copepoder.
Chr. Vid. Selsk. Forh. 1872, p. 39.

Syn: Candace pectinata, Brady.

Specific Characters.—Female. Body much more robust than in the pre-
ceding species, with the anterior division considerably vaulted above, and, seen
dorsally, oval fusiform in shape, greatest width nearly attaining half the length
and occurring in the middle, anterior extremity abruptly contracted and trans-
versely truncated at the tip, posterior slightly attenuated. Last segment of meta-
some deeply emarginated in the middle, lateral corners produced to acute posteri-

orly-pointing projections reaching beyond the middle of the genital segment.

136

Urosome conspicuously asymmetrical, genital segment somewhat irregularly dilated
in the middle, and without any lateral spines, 2nd segment forming below a sacci-
form dilatation turned somewhat to right side, last segment with an irregular dorsal
lappet curved to left side. Caudal rami likewise somewhat asymmetrical, the left
one being smaller than the right; sete about as in C. norvegica. Hye present, but
very small, sub-ventral. Anterior antennze much shorter than in C. norvegica, when
reflexed scarcely reaching beyond the genital segment, and consisting of only 23
articulations. Anterior maxillipeds rather large, but with the claw-like spines
less strong than in C. norvegica. Apical spine of outer ramus in 2nd to 4th
pairs of legs very short, not nearly attaining half the length of the terminal joint.
Last pair of legs with the terminal jomt much longer than the other 2 combined,
and falciform in shape, tapering distally, and terminating in a simple acute point,
outer edge with 3 extremely small denticles, one of which is placed at rather a
long distance from the other 2, inner edge perfectly smooth.

Male more slender than female, with the right projection of last segment
of metasome slightly larger than left, but scarcely incurved. Urosome without
any sacciform dilatation below, genital segment with the projection on right side
simple, acuminate. Right anterior antenna with the middle section considerably
more tumefied than in C. norvegica, and having at the end anteriorly a very
coarsely serrate, dark-coloured lamella. Right last leg terminating in agsomewhat
irregular chela formed by the last 2 joints.

Colour. Body semipellucid, with a faint yellowish tinge, and exhibiting
on the dorsal face of the anterior division a double row of small dark blue patches.

Length of adult female 2.70 mm., of male about the same.

Remarks.—Vhe above-described form is unquestionably Boeck’s Candace
armata. Owing to the imperfect manner in which it was recorded by that author,
it was, however, not recognized by subsequent carcinologists, and it has accor-
dingly been recorded under the name proposed by Brady several years later,
viz., that of Candace pectinata. It may be observed that, according to Dr.
Giesbrecht, the form described under this name from the Challenger Expedition,
is a different species, viz., Candacia curta of Dana. From most other species
the present form may be easily recognized, at any rate in the female sex, by
the peculiar asymmetry of the urosome.

Occurrence.—Boeck did not record the locality where he found this form.
Most probably it was Haugesund, west coast of Norway, where he made most of
his collections. I have myself taken it occasionally off Mzrdg, outside Arendal,
and in the lower part of the Christiania Fjord, at Hanke. All the specimens

were procured by the aid of the tow-net near the surface of the sea. The same

areas

species has also been taken by Mr. Nordgaard in the neighbourhood of Bergen;
and 2 specimens were further found in a plankton-sample taken during the cruise
of the “Michael Sars” in 1901, at Stat. 11, located east of Iceland.

Distribution British Isles (Brady), Atlantic Ocean, between Lat. 33°
and 50° N. (Cleve), Mediterranean (Giesbrecht).

Fam. 21. Pontellide.

Characters. Body generally strongly built, with the anterior division more
or less fusiform in shape. Cephalosome well defined from the Ist pedigerous
segment, and having often laterally a hook-hke projection, front produced below
to a strong bifurcate rostrum. Last segment of metasome with the lateral parts,
as a rule, produced behind. Urosome in female generally asymmetrical, with the
number of segments more or less reduced. Caudal sete present in the normal
number. Visual organs, as a rule, highly developed, consisting of a single pro-
tuberant ventral eye and 2 well defined dorsal eyes, each often provided with
one or 2 cuticular lenses. Anterior antenne in female 16—24-articulate; right
antenna in male distinctly geniculate, with the middle section generally greatly
tumefied. Posterior antenne resembling in structure those in the Candaciude.
Mandibles and maxillee on the whole normal. Anterior maxillipeds strongly built,
with long, anteriorly-curving spiniform sets, digitiform lobes well developed.
Posterior maxillipeds much smaller than the anterior, with the Ist basal joint
more or less expanded and carrying long sets, remaining part very narrow, and
clothed with very short sete. The 4 anterior pairs of legs of normal structure,
with the inner ramus shorter than the outer and generally biarticulate. Last
pair of legs not natatory in either of the sexes, though in female generally
biramous; those in male very asymmetrical, right leg more or less pronouncedly
cheliform. No ovisac present in female.

Remarks.—This family, answering to the subfamily Pontellina of Gies-
brecht, comprises a number of Calanoids, which are distinguished by their strongly
built body and the often vivid blue colour with which they are ornamented. Of
all the known Calanoida, they seem to be those which have reached to the highest
degree of development, this being manifested both by their unusually energetic
movements and the generally complicated structure of the visual organs. In the

19 — Crustacea.

138

restriction here adopted, the family comprises 7 distinct genera, viz., Anomalocera
Templeton, Labidocera Lubbock, Pontella Dana, Pontellopsis Brady, Lvellopsis Claus,
Monops Lubbock, Pontellina Dana and Calanopia Dana. Of these genera, only
the first 2 are represented in the fauna of Norway; the others are characteristic

of the tropical parts of the oceans.

Gen. 26. Anomalocera, Templeton, 1837.

Syn: Irenceus, Goodsir.

Pontia, Kroyer (part).

”

Generic Characters.—Body comparatively slender, with the anterior divi-
sion oblong in form. Cephalosome with distinct lateral hooks, rostrum very strong,
with the rami abruptly deflexed and acute at the tip. Last segment of metasome
well defined from the preceding one, and having the lateral lobes in female tri-
angularly pointed, in male conspicuously asymmetrical. Urosome in female con-
sisting of 3, in male of 5 segments; caudal rami more slender in male than in
female, in the latter conspicuously asymmetrical. Dorsal eyes well developed and
of the same appearance in both sexes, each with 2 cuticular lenses; ventral eye
in male enormously developed, club-shaped. Anterior antennze not very elongated,
consisting in female of 21 articulations; right antenna of male greatly swollen
in the middle. Posterior antennie with the inner ramus well defined from the
basal part, outer very small, 5-articulate. Mandibles with 7 denticles on the
cutting edge, the outer 2 claw-shaped, palp rather robust. Maxille with the
proximal appendicular lobe much larger than the distal one. Maxillipeds exhib-
iting the structure characteristic of the family. First pair of legs with the ner
ramus 3-articulate. Last pair of legs in female with the rami very unequal, the
outer one slender, biarticulate, inner very small, bidentate at the tip; right leg
in male with the chela not very strong and having both the dactylus and thumb
obtuse at the tip.

Remarks.—This genus was established by Templeton as early as the
year 1837. The genus /renwus of Goodsir is identical with that of Templeton.
It is nearly related to the typical genus Pontella of Dana, differing however
rather materially in some points, e. g. in the presence of 2 pairs of dorsal
eye-lenses, the comparatively short anterior antenne, and the structure of the
last pair of legs in both sexes. We know at present of only a single species,

to be described below.

59. Anomalocera Patersoni, Templeton.
(Pl. XCII—XCTIV):
Anomalocera Patersoni, Templeton, in Transact. Entom. Soc. London. Vol. Il, p. 35, Pl. V,

miele M35

Syn: TJrenceus splendidus, Goodsir.
Pontia Patersoni, Kroyer.

. Pontella Eugenie, Leuckart.

Specific Characters.—Female. Anterior division of body but very slightly
vaulted above, seen dorsally, oblong in form, greatest width equalling about '/; of
the length, and occurring about in the middle, anterior extremity rather broad
and triangularly pointed at the tip, posterior gradually somewhat attenuated.
Cephalosome about the length of the 3 succeeding segments combined, and some-
what depressed in its anterior part, lateral edges forming on each side, somewhat
in front of the middle, a well-marked hook-like projection, rostrum abruptly
deflexed, with the rami rather strong and acutely pointed. First segment of
metasome considerably larger than the succeeding ones, last segment compara-
tively small, with the lateral lobes of moderate size and triangularly pointed.
Urosome considerably exceeding half the length of the anterior division, and
somewhat asymmetrical, being generally turned out of the axis of the body to
the right, genital segment somewhat tumefied in the middle and produced ven-
trally on right side to a narrow rod-like projection. Caudal rami conspicuously
unequal, left ramus constricted at the base and gradually widening distally, right
considerably larger and more exstant, with the outermost seta quite short, both
rami very finely ciliated inside. Ventral eye comparatively small, though distinctly
protuberant, dorsal eyes well developed, corneal lenses placed at some distance
from them, near the lateral edges. Anterior antennz, when reflexed, reaching
about to the end of the 3rd pedigerous segment, being generally extended
obliquely anteriorly in the living animal, proximal part somewhat dilated, distal
part rather slender. Posterior antennz with the inner ramus rather fully devel-
oped, outer, on the other hand, very small, scarcely exceeding in length the
proximal joint of the imner, and much narrower. Natatory legs with the apical
spine of the outer ramus rather slender and coarsely dentate outside. Last pair
of legs with the outer ramus narrow and elongated, about twice the length of the
basal part, proximal joint linear in form, with 2 small spines outside, and produced
at the tip inside to a slender spiniform process, distal joint rather small, carrying
3 spines on the tip, the innermost much the largest and finely denticulate inside;

inner ramus very small, and produced at the end to 2 subequal diverging denticles.

140

Male somewhat more slender than female, and having the last segment

of metasome conspicuously asymmetrical, right lateral lobe much larger than left,
and produced to a slender, somewhat inflexed process. Urosome much narrower
than in female, and, as usual, 5-articulate, Ist joint on right side produced ina
triangular projection, the 2 succeeding segments slightly asymmetrical. Caudal rami
much more elongated than in female, and nearly equal. Ventral eye of extraordinary
size, sub-pedicellate or club-shaped, extending obliquely anteriorly, its broadly
rounded end being received between the rami of the rostrum. Right anterior
antenna with the middle section bulbously tumefied in its proximal part, and
carrying a slender spine pointing obliquely inwards, the last 2 joints of this
section attenuated, and each provided in front with a finely serrate lamella. Last
pair of legs without any trace of an inner ramus, left leg with the terminal joint
comparatively small, incurved, projecting at the tip to a short claw, and carrying
3 small spines outside; right leg with the chela sub-quadrangular in form, thumb
very small, dactylus somewhat spoon-shaped.
Colour. Body generally of a fine bluish green colour, with a number of
irregular dark patches on the dorsal face of the anterior division arranged in a
double row, Ist and 2nd pedigerous segment each with a median dorsal pigment-
star, consisting of a dark nucleus and numerous radiating fibres of a silvery
hue; ventral eye indigo blue.

Length of adult female 3.20 mm., of male 3.00 mm.

Remarks.—This handsome Calanoid was first described under the above
name by Templeton, and was some years afterwards recorded by Goedsir under
another name, viz., LJrenwus splendidus. Kroyer referred the species to the genus
Pontia of Milne-Edwards (= Pontella Dana). It is an easily recognizable form,
and perhaps one of our most beautiful Calanoids, being clearly distinguished both
by its unusual colouring and the very full development of the visual organs,
especially in the male.

Occurrence.

I have met with this form in several places, both off the
south and west coasts of Norway, generally congregated in great shoals. The
true habitat of this form, however, is undoubtedly the open ocean, and itis only
after heavy gales, and by the accompanying strong sea-currents, that it is occa-
sionally brought close to the shores and into the fjords. Under such circum-
stances I have found it rather plentifully at the Biological Station at Drobak,
and sometimes even in the uppermost part of the Christiania Fjord, close to the
town. Off the west coast of Norway, where it is known to the fishermen as
“Blaaaate” (blue bait), its presence in the fjords is a very good sign of the ap-

proach of the summer-herring. It is always found swimming close to the surface of

the sea, often jumping out of the water; and, as it generally occurs in great
abundance, the presence of this Calanoid in calm weather may be easily observed
by a slight disturbance of the surface, as if by fine rain. The movements of
this Calanoid are exceedingly rapid and energetic, and indeed, when kept alive
in a bottle with sea-water, it is a matter of great difficulty to catch the specimens
with the ordinary implements, viz., a small feather or a dipping-tube. When
brought under the microscope in a small quantity of water, the animal immediately
jumps off the object-glass, and in order to prevent its escape, it is therefore
necessary to add to the water a little alcohol or other narcotizing fluid.
Distribution.—British Isles (Brady), coast of France (Canu), Mediter-
ranean (Claus), Atlantic Ocean, between Lat. 36° and 67° N. (Giesbrecht), Black

Sea (Karawajew).

Gen. 27. Labidocera, Lubbock, 1853.

Syn: Pontella, Dana (part.).

= Hemipontella, Claus.

Generic Characters.—Body less slender than in Anomalocera, with the
anterior division more tumefied. Cephalosome with or without lateral hooks,
rostrum about as in Anomalocera, but somewhat smaller. Last segment of meta-
some confluent with the preceding one, lateral lobes more or less produced behind.
Urosome in female comparatively short and composed of 2 or 3 segments, that
in male 5-articulate, genital segment in female generally asymmetrical. Caudal
rami of moderate size, sometimes conspicuously unequal in female. Ventral eye
of same appearance in the 2 sexes, dorsal eyes each with a single cuticular lense,
rather small in female, greatly developed in male. Anterior antenn slender and
elongated, consisting in female of 23 articulations; right antenna in male with
the middle section moderately tumefied. Posterior antenne with the inner ramus
confluent with the basal part, outer ramus larger than in Anomalocera. Oral
parts on the whole resembling in structure those in that genus. Inner ramus in
all the natatory legs biarticulate. Last pair of legs in female with both rami
uniarticulate and less unequal than in Anomalocera; left leg in male sometimes
with a rudimentary inner ramus, right leg terminating in a very large and
perfect chela.

Remarks.—This. genus, established by Lubbock, is chiefly distinguished

from Anomalocera by the presence of only a single pair of dorsal ocular lenses,

142

which in the male are greatly developed, whereas the ventral eye is of the same
appearance in both sexes. Moreover, the last segment of the metasome is con-
fluent with the preceding one, and the inner ramus of the Ist pair of natatory
legs is biarticulate, like that in the other pairs. Finally, the structure of the
last pair of legs is somewhat different in the 2 sexes, the chela of the right leg
in male being exceedingly large and powerful. We know at present of numerous
species belonging to this genus, amounting to about 23 in all. One of these

species has been found off the Norwegian coast, and will be described below.

60. Labidocera Wollastoni, Lubbock.
(Pl. XCV & XCVI).
Pontella Wollastoni, Lubbock, in Ann, nat. hist. ser. 2, Vol. 20, p. 406, Pl. 10, 11.

Syn: Pontella helgolandica, Claus.

Specific Characters.—Female. Anterior division of body, seen dorsally,
oblong oval in form, greatest width exceeding 1/; of the length, and occurring
behind the middle, anterior extremity somewhat contracted and narrowly rounded
at the tip, posterior but slightly attenuated. Cephalosome exceeding in length
the 3 succeeding segments combined, lateral hooks well marked, rostrum abruptly
deflexed, with the rami acutely pointed. Lateral lobes of last segment of meta-
some triangular and perfectly symmetrical. Urosome comparatively short and
thick, 3-articulate, not nearly attaining '/; of the length of the anterior division,
genital segment produced dorsally to a large sacciform expansion turned somewhat
to the right, and quite overlapping the succeeding segment. Caudal rami sym-
metrical, with the setz comparatively short and thick. Dorsal ocular lenses small
and widely apart. Anterior antenne very slender, reaching, when reflexed, about
to the end of the 2nd caudal segment. Posterior antenne with both rami rather
slender, the inner one the longer. Last pair of legs rather robust, both rami
well developed, lanceolate, without any denticles or sete, the outer one the larger.

Male more slender than female, with the lateral lobes of last segment of
metasome shorter and more obtuse. Urosome narrower and perfectly symmetrical,
Ist segment not produced on right side. Caudal rami more elongate than in
female, with the sete rather slender. Dorsal ocular lenses exceedingly large and
placed near together. Right anterior antenna with a hook-like projection on the
penultimate joint of the middle section and a coarsely serrate lamella on the last
one; antepenultimate joint of the terminal section produced at the end anteriorly

to a slender, rod-like process. Last pair of legs very asymmetrical, left leg provided

1435

with a thin deflexed Jamella issuing from inside the basal part, and terminating
in 2 unequal digititorm processes, terminal part somewhat complanate, biarticulate,
with the distal joint discoidal and armed outside with 3 slender spines; right leg
very strongly built, with the chela exceedingly large and tumid, both the dactylus
and thumb sharply pointed, palmar edge irregularly indented, with an obtuse
projection in the middle.

Colowr.—Body semipellucid, with a yellowish green tinge, and in female
generally with 3 dark yellow transverse patches on the dorsal face of the anterior
division; dorsal ocular lenses in male highly refractive.

Length of adult female 2.40 mm., of male 2.20 mm.

Remarks.—This form was first described by Lubbock as a species of the
genus Pontella of Dana. The Pontella helgolandica of Claus is unquestionably
identical with Lubbock’s species. It is easily recognized from the 2nd Norwegian
Pontellid, Anomalocera Paterson, though agreeing closely with some of the exotic
species of the present genus.

I have taken this form occasionally at Merde, outside Aren-

Occurrence.
dal, and in the lower part of the Christiania Fjord. Some few specimens were
also found in a plankton-sample taken by Dr. Hjort in the Langesund Fjord,
and Mr. Nordgaard has observed this form in the neighbourhood of Bergen. Like
all the other Pontellide, it is a true pelagic form, occurring more generally in
the open ocean, close to the surface of the sea.

Distribution.—British Isles (Brady), Heligoland (Claus), coast of France
(Canu), Mediterranean (Giesbrecht), Atlantic Ocean, between Lat. 36° and 55° N,

(Giesbrecht).

Fam. 22. Parapontellide.

Characters.—General form of body somewhat resembling that in the
Pontellide. Cephalosome well defined from the 1st pedigerous segment, front
without any rostrum, but carrying below 2 soft tentacular appendages. Last seg-
ment of metasome united with the preceding one, and in male conspicuously
asymmetrical. Urosome composed in female of 3, in male of 5 segments. Caudal
rami in both sexes perfectly symmetrical, with the full number of setz. A small

ventral eye present, and moreover a rather large central eye: no cuticular lenses

144

present. Anterior antennze comparatively short, with the number of articulations
somewhat reduced; right antenna in male distinctly geniculate. Posterior antennee
with both rami well developed. Oral parts, especially the mandibles and maxille,
of rather anomalous structure. Anterior maxillipeds much more strongly built
than the posterior. The 4 anterior pairs of legs resembling in structure those
in the Pontelide. Last pair of legs not natatory in either of the sexes; in
female biramous, in male uniramous, right leg in the latter not cheliform.
Remarks.—TVhis family is here taken in a much more restricted sense
than even the subfamily Parapontellinew, which, according to Dr. Giesbrecht, com-
prises the 3 genera Parapontella, Acartia and Corynura. In my opinion, these
3 genera are so widely different, that each of them ought to be regarded as the
type of a separate family. The present family accordingly, in the restriction here
adopted, comprises only the genus Parapontella of Brady, which, although in
some respects exhibiting a slight resemblance to the Pontellide, in reality differs
very materially in several structural features, for instance in the want of the
strong bifurcate rostrum characteristic of that family, in the very different structure
of the posterior antenne and oral parts, and finally in the not chelate right last
leg of the male. The solitary species of the genus as yet known seems also to

differ pronouncedly in habits from the Pontellide.

Gen. 28. Parapontella, Brady, 1878.

Syn: Pontellina, Lubbock (not Dana).

Generic Characters.—Body comparatively robust, with the anterior division
considerably tumefied. Cephalosome weil arched, front scarcely at all produced
below, tentacular appendages very delicate, recurved. Lateral parts of last seg-
ment of metasome in female rounded off, im male produced on right side. Uro-
some in female perfectly symmetrical, in male with some of the segments produced
on right side. Caudal rami sublinear in form, and of same appearance in the
2 sexes; all the sete well developed. Anterior antennz composed in female of
20 articulations, last one very small and imperfectly defined; right antenna in
male with the joints of the middle section somewhat irregular, terminal section
composed of only 2 joints. Posterior antenne with the inner ramus imperfectly
defined from the basal part, outer ramus longer than the inner. Mandibles

rather strong, with the outer cutting teeth unguiform, palp of somewhat unusual

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PRINCIPAL WORKS ON CALANOIDA.

Bard, W.
Boeck, A.

Brady, G. S.

Canu, E.
Claus, C.
Cleve, P. T.

Dana, LD.
Giesbrecht, W.

The Natural History of the British Entomostraca. 1850.
Oversigt af de ved Norges Kyster iagttagne Copepoder. Chr.
Vid. Selsk. Forh. 1864.

Nye Slegter og Arter af Saltvandscopepoder. Chr. Vid. Nelsk.
Forh. 1872.

A Monograph of the free and semiparasitic Copepoda of the
British Islands, Vol. I. 1878.

Report on the Copepoda collected by H. M.S. Challenger during
the years 1873—76. 1883.

A Revision of the British species of fresh-water Cyclopidee and
Calanide. ‘l'rans. North. Durh. Newe.-on-Tyne, Vol, XE is8o1-
Les Copépodes marins du Boulonnais. Bullet. Scient. 1888 & 1890.
Les Copépodes du Boulonnais. 1892.

Die freilebenden Copepoden, mit besonderer Beriicksichtigung der
Fauna Deutschlands, der Nordsee und des Mittelmeeres. 1863.
The Seasonal Distribution of Atlantic Plankton Organisms, 1901.
Crustacea of the United States Exploring Expedition. 1855.
Die freilebenden Copepoden der Kieler Féhrde. 4te Bericht.
Commiss. Wiss. Unters. Deutschen Meeres. 1882.

Fauna und Flora des Golfes von Neapel. XIX Monographie:
Pelagische Copepoden. 1892.

-—— & Schmeil. Copepoda gymnoplea in “Das Thierreich”. 1898.

~Guerne, J. & Richard, J. Révision des Calanides d’eau douce. 1889.

Herrick; C. L. & Turner, C. H. Synopsis of the Entomostraca of Minnesota.

Jurine, L.

2nd Report of the State Zoologist. 1895.
Histoire des Monocles qui se trouvent aux environs de Geneve.
1820.

Karawajew, W.

Kroyer, H.
LTilljeborg, W.

a

Beitriige zur Fauna der Copepoden des’ Schwarzen Meeres (Text
in Russian). 1894.
Karcinologiske Bidrag. Naturh. Tidsskrift 1846—1849.

De Crustaceis ex ordinibus tribus in Scania occurrentibus. 1853.

Lubbock, Sir John. On some Oceanic Entomostraca collected by Capt. Toynbee.

Milne- Edwards,
Miller, O. Fr.

Nordqvist, O.
Sars, G. O.

Schmeil, O.

Scott, Th.

Trans. Linn. Soc., Vol. XXIV. 1863.

H. Histoire Naturelle des Crustacés. 1834.

Entomostraca sive Insecta testacea que in aquis Danie et Nor-
vegize reperit. 1785.

Die Calaniden Finlands. 1888.

Oversigt af de indenlandske Ferskvandscopepoder. Chr. Vid.
Selsk. Forh. 1863. :
Pelagic Entomostraca of the Caspian Sea. Ann. Mus. Zool. Acad.
St. Petersburg. 1897. |
The Cladocera, Copepoda and Ostracoda of the lana Expedition.
Ann. Mus. Zool. Acad. St. Petersburg. 1898.

The Norw. North Polar Expedition 1893—96. Scientific Results.
V. Crustacea. 1900.

Deutschlands freilebende Siisswasser Copepoden, Vol. TT. Cen-
tropagidee. Bibliotheca Zoologica, Part 21. 1896.

Report on Entomostraca from the Gulf of Guinea. Trans,.Linn.
Soc. London. Vol. VI, Part 1. 1894.

Several papers in the Annual Reports of the Fishery Board for
Scotland.

So LEM ATIC Jaisi

OF THE SPECIES DESCRIBED IN THE PRESENT VOLUME.

Amphascandria.

Calanide.

Calanus, Leach.
finmarchicus, Gunner.
helgolandicus, Claus.
hyperboreus, Kroyer.

Eucalanidee.

Rhinealanus, Dana.
nasutus, Giesbrecht.

Paracalanide.

Paracalanus, Boeck.
parvus, Claus.

Pseudocalanide.

Pseudoecalanus, Boeck.
elongatus, Boeck.
gracilis, G. O. Sars.

Microcalanus, G. O. Sars.
pusillus, G. O. Sars.

Spinoealanus, Giesbrecht.
abyssalis, Giesbrecht.

Axtideidz.

Atideus, Brady.
armatus, Boeck.

Atideopsis, G. O. Sars.
rostrata, G. OF Sars.
Chiridius, Giesbrecht.
armatus, Boeck.
obtusifrons, G. O. Sars.
Gaidius, Giesbrecht.
tenuisprmus, G. O. Sars.
brevispinus, G. O. Sars.
Undinopsis, G. O. Sars.
Bradyi, G. O. Sars.
similis, G. O. Sars.
Bryaxis, Boeck.

brevicornis, Boeck.

Euchetide.

Eucheta, Philippi.
norvegica, Boeck.
glacialis, Hansen.
barbata, Brady.

Phaénnide.

Pseudophaenna, G. O. Sars.
typica, G. O. Sars.
Xanthocalanus, -Giesbrecht.
borealis, G. O. Sars.

propingvus, G. O. Sars.

Scolecithricide.

Amallophora, Scott.
magna, Scott.
brevicornis, G. O. Sars.
Seolecithricella, G, O. Sars.
minor, Brady.

Isokerandria.

Diaixide.

Diaixis, G. O-sSars.
hibernica, Scott.

Stephidez.
Stephos, Scott.

lamellatus, G. O. Sars.

Scotti, G. O. Sars.
Parastephos, G 0. Sars.

pallidus, G. O. Sars.

Tharybide.

Tharybis, G. O. Sars.
macrophthalma, G. O. Sars.

Pseudocyclopiide.

Pseudocyclopia, Scott.
stephoides, Thompson.

Heterarthrandria.
Centropagide.

Centropages, Kréyer.
typicus, Kroyer.
hamatus, Lilljeborg.

Isias, Boeck.
clavipes, Boeck.

Limnocalanus, G. O. Sars.
macrurus, G. O. Sars.

Diaptomide.

Diaptomus, Westwood.
castor, Jurine. |
denticornis, Wierzejsky.
bacillifer, Koelbel.
laticeps, G. O. Sars.
laciniatus, Lilljeborg.
gracilis, G. O. Sars.
graciloides, Lilljeborg.

Temoride.

Temora, Baird.
longicornis, Miller.
Eurytemora, Giesbrecht.
velox, Lilljeborg.
hirundoides, Nordqvist.
lacustris, Poppe.
Heterocope, G. O. Sars.
saliens, Lilleborg.
borealis, Fischer.
appendiculata, G. O. Sars.

Metridiide.

Metridia, Boeck.
longa, Lubbock.
| lucens, Boeck.
Pleuromamma, Giesbrecht.
robusta, Dahl.

Heterorhabdide2.

Heterorhabdus, Giesbrecht.
norvegicus, Boeck.

Haloptilus, Giesbrecht.
longicornis, Claus.
acutifrons, Giesbrecht.

Arietellide.

Sscottula, G. O. Sars.
ineqvicornis, G. O. Sars.

Paramisophria, Scott.
Cluthe, Scott.

ous

Pseudocyeclopide. | Labidocera, Lubbock.
Wollastoni, Lubbock.
Pseudocyclops, Brady.
obtusatus, Brady. é
ata Parapontellidee.
Candaciide. Parapontella, Brady.
Candacia, Dana. brevicornis, Lubbock.
norvegica, Boeck.
armata, Boeck. AcCartiide.
: Acartia, Dana.
Pontellide.

longivemis, Lilljeborg.
Anomalocera, Templeton. Clausi, Giesbrecht.
Paterson, Templeton. discaudata, Giesbrecht.

145

appearance, the basal part being very slender, almost cylindric in form, inner
ramus abruptly reflexed, outer quite rudimentary and occurring at rather a long
distance from the inner. Maxillee with the palp much produced, vibratory plate
rudimentary. Anterior maxillipeds with strong, claw-like spines on the distal part,
proximal lobes very small. Posterior maxillipeds with the 1st basal joint con-
siderably produced in front, and carrying strongly developed sete, distal part
very small, with the sete rudimentary. Inner ramus of Ist pair of legs 3-articu-
late, that of the 3 succeeding pairs biarticulate. Last pair of legs in female with
both rami uniarticulate, outer slender and linear, inner short, conical; those in
male 3-articulate, terminal joint in both legs spatulate, though of somewhat diffe-
rent form.

Remarks.—This genus was established in the year 1878 by Prof. Brady,
to include a form previously described by Lubbock as a species of the genus
Pontellina of Dana. The removal of this form, not only from that genus, but
also from the family Pontellide, is justified by a number of well-marked differences,
which have been mentioned in the preceding pages. The genus comprises at

present only a single species, to be described below.

61. Parapontella brevicornis (Lubbock).
(Pl. XCVIL & XCVIID.
Pontellina brevicornis, Lubbock, in Ann. Nat. Hist., 2nd series, Vol. XX, p. 407, Pl. XI, figs. 4—8.

Specific Characters—Female. Anterior division of body, seen dorsally,
oval in form, greatest width slightly exceeding half the length, and occurring in
the middle, anterior extremity somewhat contracted and narrowly rounded at the
tip, posterior but slightly attenuated. Cephalosome about the length of the 3
succeeding segments combined, and evenly vaulted above. Lateral lobes of last
segment of metasome somewhat deflexed and narrowly rounded at the tip. Uro-
some scarcely attaining half the length of the anterior division, genital segment
slightly tumefied in its proximal part and rather protuberant below, 2nd segment
armed at the posterior edge with 2 sub-dorsal, posteriorly-pointing spines. Caudal
rami about 3 times as long as they are broad, sublinear in form, and scarcely
divergent, marginal sete of moderate length, the outermost issuing from the
outer edge, at some distance from the others. Anterior antenne much shorter
than the anterior division of the body, reaching, when reflexed, to about the end
of the 2nd pedigerous segment, proximal part somewhat tumefied and clothed

inside with a number of partly plumose sete, apical bristles likewise ciliated.

20 — Crustacea.

146

Posterior antenne with the outer ramus considerably longer than the inner, and
composed of 5 joints only, last joint rather narrow, with only 2 apical sete. Last
pair of legs with the outer ramus very narrow and slightly curved, being pro-
duced at the end inside to a spiniform projection, tip armed with a slender spine,
outer edge with 2 much smaller spines, the distal one placed near the tip; inner
ramus about half the length of the outer, and produced at the tip to 2 short
digitiform projections.

Male much more slender than female, with the right corner of last seg-
ment of metasome remarkably expanded and conically produced behind. Uro-
some very slender and somewhat asymmetrical, being generally turned out of
the axis of the body to the left, 3rd and 4th segments each produced on
right side to a small dentiform process. Right anterior antenna longer than left
and much more strongly built, middle section moderately tumefied in its proximal
part, its penultimate joint produced at the end anteriorly to a short dentiform
projection, last joint with a serrated lamella in front; terminal section exserted
at the tip to a strong mucroniform projection, at the base of which, posteriorly,
issue the apical bristles. Last pair of legs rather asymmetrical, the right one
being the larger, with the 1st joint considerably dilated, and produced inside to
a narrow digitiform process; 2nd joint of both legs with a short dentiform pro-
jection inside; terminal joint of right leg somewhat lozenge-shaped, being suddenly
dilated near the base, and exserted at the end to a slender acuminate lappet
pointing straight downwards, that of left leg broadly oval in outline and partly
ciliated on the edges, apical lappet quite short and pointing inwards, outer edge
with 2 dentiform projections.

Colour. Body of female generally pellucid, with a faint yellowish tinge,
and exhibiting dorsally at the end of each of the pedigerous segments an inter-
rupted transverse band of a dark reddish hue; in some cases, however, rather
deeply tinged with a reddish brown pigment, both on the anterior and posterior
divisions. Body of male always of a uniform yellowish hue.

Length of adult female 1.55 mm., of male 1.35 mm.

Remarks.—This form was described by Lubbock as early as the year 1857,
and was at that time referred to the genus Pontellina of Dana, apparently owing
to a slight resemblance in the general form of the body. It is, however, in
reality very different from that genus, and is also easily recognizable from any
of the other known Calanoida.

Occurrence.—I have met with this Calanoid occasionally in 3 different
localities of the west coast of Norway, viz., Molde, Christiansund and Kalvaag.

In all these localities it occurred close to the shore, at a depth of a few fathoms,

aC.

among alge. On the other hand, I have never met with it in any of the numer-
ous plankton-samples examined by me, for which reason I have come to the con-
clusion that, at any rate off the Norwegian coast, this Calanoid is a strictly
littoral form. It moves in the usual manner, now proceeding rather slowly in a
somewhat jumping manner by rhythmical strokes of the posterior antenne and
mandibular palps, now starting away more suddenly by employing the natatory
legs and the urosome.

Distribution.— British Isles (Brady), coast of France (Canu), Mediterranean
(Giesbrecht), Atlantic Ocean between 50° and 59° N. Lat. (Giesbrecht).

Fam 23=..Acartiide:

Characters.—Body more or less slender, with the anterior division but
slightly vaulted. Cephalosome well defined from the 1st pedigerous segment;
front without any rostrum. Last 2 segments of metasome united. Urosome con-
sisting in female of 3, in male of 5 segments. Caudal rami with the full number
of seta. A single eye present. Anterior antenne very slightly attenuated and of
a peculiar nodular appearance, the articulations being rather irregular and some-
times indistinctly defined, bristles very unequal; right antenna in male slightly
transformed, and imperfectly geniculate. Posterior antenne very delicate, with
the inner ramus very slender, outer poorly developed. Oral parts conspicuously
differing from those in other Calanoids; posterior maxillipeds, however, built upon
a somewhat similar type to that in the Pontellide. The 4 anterior pairs of legs
very slender and delicate, with unusually long natatory sete; inner ramus in all
these pairs biarticulate. Last pair of legs not natatory, uniramous in both sexes,
very small in female, somewhat larger and subprehensile in male. No ovisac
present in female.

Remarks.— This family is established to include the genus Acartia of
Dana, which in several respects differs materially from the other known Calanoida,
representing quite a particular type. It is only in the structure of the maxillipeds
that some agreement is found to the Pontellide@, to which family this genus has
often been referred; but otherwise it is widely different. In addition to the typi-
‘cal genus, another nearly-allied genus has recently been established by Th. Scott

as Paracartia. Only the former genus is represented in the northern seas.

Gen. 29. Acartia, Dana, 1846.

Syn: Dias, Lilljeborg.

Generic Characters.—Form of body slender and elegant. Cephalosome
attenuated anteriorly, with the front unarmed, or in some cases carrying 2 deli-
cate tentacular filaments below. First segment of metasome much larger than the
others; lateral parts of last segment generally rounded. Urosome of moderate
size, genital segment in female comparatively large, penultimate segment in male
very short, and imperfectly defined from the last one. Caudal rami of different
form in the different species, and, as a rule, shorter in male than in female;
appendicular bristle well developed and finely plumose, arising with a bulbous
base from the dorsal face of the rami. Eye comparatively large and placed close
to the front. Anterior antennze in female consisting of 17 or 18 articulations,
some of the bristles rather elongated and partly plumous; those in male with
some of the articulations confluent, middle section of right antenna very slightly
tumefied, terminal section consisting of 3 articulations. Posterior antenne with
the junction of the inner ramus with the basal part imperfectly defined, and having
the distal joint unusually prolonged, outer ramus consisting of 3 joints only, the
outer 2 very small. Anterior lip trilobate, with the middle lobe very prominent.
Mandibles not very strong, outermost cutting tooth larger than the others and
claw-shaped, palp with the inner ramus imperfectly separated from the basal part
and, like the outer, carrying very long and slender sete. Maxille with a single
appendicular lobe, inner ramus of palp replaced by a plumose seta, outer ramus
large and reflexed, with very long sete. Anterior maxillipeds short and stout,
with long curved spines anteriorly, digitiform lobes well developed. Posterior
maxillipeds resembling those in the Pontellidw. Natatory legs without any plumose
seta inside the Ist basal joint, 2nd basal joint of 4th pair carrying a slender
deflexed seta at the outer corner; outer ramus in this and the 2 preceding pairs
without distinctly defined spines outside, each of the joints being only produced
at the end to a short dentiform projection, apical spine very slender, sword-
shaped, with the outer edge closely serrate. Last pair of legs in female 3-arti-
culate, 2nd joint somewhat dilated and carrying a long plumose seta outside,
terminal joint gradually exserted to a slender point, which in some cases is spini-
form, in others setiform; those in male 4-articulate and somewhat asymme-
trical, right leg the larger, with some of the joints lamellarly expanded inside,
terminal one securiform or slightly hooked; left leg with the terminal joint some-
what spoon-shaped.

149

Remarks.—This genus was established by Dana as early as the year 1846,
to comprise some species chiefly from the Pacific Ocean. The genus Dias of
Prof. Lilljeborg is unquestionably identical with Dana’s genus. It is easily re-
cognizable by the slender, pellucid body, and the very delicate and peculiar structure
of the several appendages. We know at present of a considerable number of
species from different tracts of the oceans, amounting to about 20 in all. Some
of them, however, may probably be referable to the nearly-related genus Para-
cartia of Scott. To the fauna of Norway belong 3 species, to be described below.
A 4th species, A. bifilosa Giesbrecht, will also in all probability be found to
occur off the Norwegian coast, as it has been observed both in the Baltic and

off the British coast.

62. Acartia longiremis (Lilljeborg).
(Pl. XCIX & C).
Dias longiremis, Lilljeborg, De Crustaceis ex ordinibus tribus in Scania occurreutibus,
Dey LSP PIE) XOX:

Specific Characters.—Female. Anterior division of body, seen dorsally,
oblong fusiform in outline, greatest width about equalling '/; of the length, an-
terior extremity somewhat contracted and obtusely truncated at the tip, posterior
gradually attenuated. Cephalosome attaining nearly half the Jength of the anterior
division, front without any trace of tentacular filaments below. Lateral lobes of
last segment of metasome rounded off at the tip, and each carrying dorsally a
rather conspicuous, delicate spinule. Urosome about equal in length to 1/3 of the
anterior division, genital segment fully as long as the other 2 combined, and, like
them, clothed both laterally and at the posterior edge with scattered, very delicate
spinules. Caudal rami sublinear in form, their length considerably exceeding that of
the anal segment, and slightly asymmetrical, right ramus projecting somewhat
beyond the left, and having the appendicular bristle nearer to the tip; marginal
sete densely plumose and somewhat divergent. Anterior antenns, when reflexed,
reaching about to the middle of the genital segment, none of the articulations
dentiferous. Length of apical spine of outer ramus in 2nd to 4th pairs of legs
considerably exceeding that of the whole ramus. Last pair of legs with the termi-
nal joint exserted to a slender setiform point, and somewhat curved in the middle.

Male considerably smaller than female and easily recognizable by the
structure of the anterior antennze and urosome. Caudal rami comparatively shorter
than in female, otherwise of a very similar appearance. Last pair of legs of

moderate size, 2nd and 3rd joints of right leg each expanded inside in to a rounded

150

lamellar projection, terminal joint of same leg securiform, that of left leg com-
paratively. broad,

Colour. Body in both sexes highly pellucid, with a very faint tinge
of blue. Length of adult female reaching to 1.25 mm., of male to 1.05 mm.

Remarks.—This form was first described by Prof. Lilljeborg in his well-
known treatise on the Entomostraca of Skane under the name of Dias longirenus.
It is not easy at once to distinguish this form from some of the other species,
to which it bears a great similarity. On a closer examination, however, it may
be readily recognized in both sexes by the slender and delicate spinule occurring
on the dorsal face of the lateral lobes of the last segment of the metasome, as
also by the relative length of the anterior antenne and caudal rami. More-
over the apical spine of the outer ramus in the 2nd to 4th pairs of legs is more
elongated than in most other species, and the difference in the last pair of legs
in the female is very distinctly marked by the slenderness of the terminal joint,
which is exserted to a very thin, flexible point, whereas in most other species
this joint is pronouncedly spiniform.

Occurrence.—This Calanoid is distributed along the whole Norwegian coast,
from the Christiania Fjord to Vadso, sometimes occurring in great numbers. It
is a true pelagic form, being often met with far out at sea, and at the very
surface. Not unfrequently, however, it is brought by the current close to shore;
and it is even often found in tidal pools together with Paracalanus parvus and
Temora longicornis. It moves with great rapidity in abrupt bounds.

Distribution.—British Isles (Brady), Kattegat (Lilljeborg), the Baltic (Gies-
brecht), Gulf of Finland (Nordqvist), Firoes Isles (Cleve), Iceland and southern
Greenland (idem), Spitsbergen, polar basin, north of the New Siberian Islands

(the present author).

63. Acartia Clausi, Giesbrecht.
(RICH:
Acartia Clausii, Giesbrecht, Fauna & Flora des Golfes von Neapel. Pelagische Copepoden, p. 507,
P). 30. figs. 2, 4, 13—15, 17, 28, 36, 47; Pl. 42, fir. 32; Pl. 43, figs. 3, 5, 14.

Syn: Dias longiremis, Claus (not Lilljeborg).

Specific Characters.—Female. Very like the preceding species both in
size and general appearance, and, like the latter, without any trace of tentacular
appendages in front. Lateral lobes of last segment of metasome, however,
without the dorsal spinule found in A. longiremis, but having the-edge armed with

from 4 to 6 extremely small and closely set denticles. Urosome with the first 2

151
segments clothed at the end dorsally with a transverse row of still smaller dent-
icles, but having no lateral spinules. Caudal rami comparatively shorter than in
A. longiremis. Anterior antennz likewise somewhat shorter, scarcely exceeding
the length of the anterior division of the body, 5th articulation with a distinct
denticle in front. Length of apical spine of outer ramus in 2nd to 4th pairs of
legs scarcely exceeding that of the ramus. Last pair of legs with the terminal ©
joint produced to a strong claw-like spine minutely spinulose outside.

Male resembling that of the preceding species, but having the caudal rami
comparatively shorter, and nearly as broad as they are long. Last pair of legs
very like those in the male of A. longivemis, though haying the terminal joint of
right leg considerably narrower and that of left leg less expanded.

Colour.—Body in both sexes extremely pellucid and nearly colourless.

Length of adult female 1.15 mm., of male 1.00 mm.

Remarks.—This form is so very like the preceding species that, without
a close examination, it may readily be confounded with it. This has also actually
been done by Claus, who described it as Dias longiremis Lilljeborg; and Brady
also seems to have confounded the 2 species. Dr. Giesbrecht, however, has pointed
out some minute differences between them, and as these differences are fairly
constant, they seem to justify the specific distinction of the two forms. The most
conspicuous distinctive characters are the different armature of the lateral lobes
of the last segment of the metasome and of the urosome, as also the compara-
tively shorter anterior antennz and caudal rami in the present species. The last
pair of legs in the female, moreover, conspicuously differ from those in A. lon-
giwvenus in the form of the terminal joint; and these legs in the male also exhibit
some slight differences, as shown by the figures here given.

Occurrence.—Off the south and west coasts of Norway this form is fully
as common as A. longivenis, in company with which species it is often found.
On the other hand, I have never met with it in any of the samples of plankton
from the Arctic Ocean. It accordingly seems to be a more southern form than
A. longivemis, and this assumption is also confirmed by what is at present known
of its foreign distribution.

Distribution.— British Isles (Scott), Faroe Isles (Cleve), Heligoland (Claus),
coast of France (Canu), Mediterranean (Giesbrecht), Black Sea (Karawajew),
Azores (Cleve), Atlantic Ocean between 36° and 61° N. Lat. (Giesbrecht); Gulf
of Guinea (Scott).

64. Acartia discaudata, Giesbrecht.
(Pl. CI).
Dias discaudatus, Giesbrecht, Die freilebenden Copepoden der Kieler Féhrde. te Bericht. d.
Commiss. Unters. Deutsch. Meere, p. 148, Pl. IIJ, figs. 4, 22, 23; Pl. V, fig. 18; Pl. VI, fig. 17;
Pl. VII, figs. 32, 33; Pl. IX, fig. 30.

i=)

Specifie Characters.—Female. Anterior division of body of a form similar
to that in the 2 preceding species. Front without any tentacular filaments. La-
teral lobes of last segment of metasome rounded off and quite smooth. Urosome
likewise without any traces of spinules or denticles, and rather robust, genital
segment very large, conspicuously dilated in its proximal part, and very pro-
tuberant below in the middle; 2nd segment terminating dorsally in a rounded
protuberance; 3rd segment flattened and considerably expanded distally. Caudal
rami of rather an unusual appearance, being bulbously dilated, and rounded oval
in form, with the marginal sete comparatively short and conspicuously dilated at
the base. Anterior antennee about the length of the anterior division of the body,
and without any denticles in front. Last pair of legs resembling those in A.
Clausi, the terminal joint being spiniform, though somewhat less strong than in
that species.

Male resembling that of the 2 preceding species, though perhaps less
slender. Urosome of normal appearance, the caudal rami not, as in the female,
bulbously dilated, but of a similar form to that in the male of A. Clausi. Last
pair of legs considerably larger than in either of the 2 preceding species, right
leg much elongated, being more than twice as long as the left, with the lamellar
expansions inside the 3 first joimts comparatively small, terminal joint rather
narrow, almost claw-like.

Colowr.—Body of female semipellucid, with a distinct bluish grey hue;
that of male paler.

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

Remarks.—TVhis form may at once be distinguished from the other known
species, at any rate in the female sex, by the peculiar structure of the urosome,
but more especially by the greatly dilated caudal rami. The male differs less
conspicuously, though the last pair of legs exhibit well marked peculiarities.
Another distinguishing character not mentioned in the above diagnosis, is the
large size and peculiar sac-like form of the spermatophore often found attached
to the genital segment of the female.

153

Occurrence.—\ have hithertho only met with this form in 2 localities of
the Norwegian coast, viz., Bratholmen and Skjerjehavn, the former situated at
some distance south of Bergen, the latter at the mouth of the Sogne Fjord. In
both these localities it occurred occasionally close to the shore, together with
A. longiremis, from which it was at once distinguished by its darker blue colour.

Distribution.—The Baltic (Giesbrecht), Scottish coast (Scott), coast of

France (Canu).

21 — Crustacea.

SUP PEE MENT:

Page 15. Rhinealanus nasutus, Giesbr.
Remarks.—The form recorded by Th. Scott as FR. gigas, Brady, is un-
questionably the present species.
Distribution.—Scottish coast (Scott).

Page 18. Paracalanus parvus (Claus).
Distribution.—Black Sea (Karawajew), Gulf of Guinea (Scott).

Page 21. Pseudocalanus elongatus, Boeck.
Distribution.—Black Sea (Karawajew).

Page 21. The following species should be added:

Pseudocalanus gracilis, G. O. Sars.
(Suppl. Pl. I).

Specific Characters.— Female. Body of still more slender form than in
the typical species, with the anterior division, seen dorsally, narrow oblong in
form, greatest width scarcely attaining '/; of the length; frontal part conspicuously
projecting, and, seen laterally, almost angularly curved in the middle. Lateral
parts of last segment of metasome obtusely rounded. Urosome very slender,
though scarcely exceeding half the Jength of the anterior division. Caudal rami
comparatively narrower than in P. elongatus, and more divergent. Anterior an-
tennz more elongated, reaching, when reflexed, to the end of the 3rd caudal
segment. Legs considerably more slender than in the typical species, with both
rami very narrow. Ovisac rather large, rounded oval in form, and somewhat
flattened, containing a number of globular, highly pellucid ova.

Male resembling that of P. elongatus, but having the anterior antenne
considerably longer. Last pair of legs of a structure very similar to that in the
male of the said species.

155

Colour not yet ascertained.

Length of adult female 1.65 mm., of male 1.15 mm.

Remarks.—This form, though nearly allied to the typical species, is un-
questionably distinct, differing, as it does, not only in the more slender form of
the body and the gibbously produced frontal part, but also in the greater length
of the anterior antennz, and the more slender form of the iatatory legs.

Occurrence.

This form occurred not unfrequently in some of the plankton-
samples taken during the cruise of the “Michael Sars”, 1909, in the open sea
between Finmark and Bear Island; but as the specimens were more or less
damaged, and moreover, as shown by the structure of the urosome, had not
arrived at sexual maturity, their specific difference from P. elongatus was less
apparent, for which reason I at first only regarded this form as a variety of the
typical species. It was only by the examination of another, sample taken by
Mr. Amundsen early in the spring of the following year from about the same tract,
that I could convince myself of the distinctness of the present form. This sample
contained several fully adult and admirably preserved female specimens with
the rather large ovisac still attached to the genital segment, and also some few
adult male specimens. In the same sample a number of comparatively large,
and likewise ovigerous, specimens of P. elongatus also occurred, and it was very
easy to distinguish between these 2 species, on account of the rather different
shape of the frontal part, and the difference in the length of the anterior antenne.
That this undoubledly true arctic form also occasionally occurs in the immediate
neighbourhood of the Norwegian coast, was proved by the examination of one
of the plankton-samples taken during the cruise of the ,,Michael Sars” in the
Lyngenfjord, Finmark. This sample contained some young specimens of a Pseu-

docalanus evidently belonging to the present species.

The following genus is also to be added:

Microcalanus, G. O. Sars 1901.

Syn: Pseudocalanus, G. O. Sars (part).

Generic Characters.—Body of comparatively small size, and rather short
and compact form, recalling that of Paracalanus. Cephalosome completely coa-
lesced with the Ist pedigerous segment; front carrying 2 extremely small tenta-
cular appendages below. Urosome in female comparatively short, with the genital

segment more or less dilated, in male consilerably more slender. Caudal rami

156

small, each with 4 subequal apical sete. Anterior antenne more or less slender,
composed in female of 24 articulations, and in male transformed in much the
same manner as in Pseudocalanus. Posterior antenne and oral parts resembling
in structure those parts in the said genus. Posterior maxillipeds, however, more
slender. and having the terminal part reflexed. Natatory legs on the whole built
upon the same type as in Pseudocalanus. Last pair of legs in female wholly
absent, in male comparatively small and very asymmetrical, left leg slender,
6-articulate, right very small, 3-articulate, last jot not stylform.

Remarks.—As 1 stated on page 20, it is now my opinion that the small
Calanoid described from Nansen’s Polar Expedition as Psewdocalanus pygneus
should more properly be regarded as the type of a separate genus, for which
the name Microcalanus was proposed. The correctness of this view has now been
still further confirmed by the discovery off the Norwegian coast of another still
smaller Calanoid, which is evidently congeneric with the polar form, though ap-

parently specifically distinct. This form is described below.

Microcalanus pusillus, G. O. Sars, n. sp.
(GSinjyo IA Wij ks IAL WO iaves, 1h)

Specific Characters.—Female. (General form of body resembling that of
M. pygmeus, the anterior division being rather tumid and, seen dorsally, of oval
form, greatest width almost attaining half the length, both extremities abruptly
contracted, the anterior one narrowly rounded at the tip. Cephalosome together
with the united Ist pedigerous segment occupying */; of the anterior division,
dorsal margin evenly curved in front. Lateral lobes of last segment of metasome
somewhat appressed and rounded off at the tip. Urosome about equal in length
to '/;. of the anterior division, genital segment conspicuously dilated in the
middle. Caudal rami scarcely longer than they are broad, apical sete of moderate
length. Eye wholly absent. Anterior antenne much shorter than in the typical
species, scarcely reaching, when reflexed, beyond the genital segment. Natatory
legs less slender than in VM. pygmeus, terminal joint of outer ramus in 2nd to
4th pairs comparatively broader, with the apical spine remarkably dilated, cul-
tellate in shape, and very coarsely serrate outside.

Male rather unlike the female in general appearance, the anterior division
being still shorter and more tumid, whereas the urosome is much more slender
than in female, fully equalling half the length of the anterior division. Anterior
antenne with the proximal part rather dilated and clothed anteriorly with large

Mn

curved sensory appendages, 7th jomt very elongated and apparently formed by
the coalescence of 5 articulations. Oral parts, as in the male of Pseudocalanus,
much reduced. Last right leg scarcely '/; as long as the left, terminal joint
simple, rounded.

Colour.—Body in both sexes highly pellucid and almost colourless.

Length of adult female scarcely exceeding 0.70 mm., that of male about
the same.

Remarks.—This dwarf Calanoid, perhaps the smallest of all hitherto
known forms, is closely allied to the polar species, M. pygmeus, though differing
conspicuously in the much shorter anterior antenne, as also in the structure of
the natatory legs, but more especially in the pecuhar development of the apical
spine of the outer ramus. It may here be remarked that the male specimen
figured on Pl. XXII of my Account of the Crustacea of the Norwegian North
Polar Expedition, and described as the male of Spinocalanus longicornis, most
certainly does not belong to that form, but to Microcalanus pygmeus, which is
proved by its great similarity to the male of the present species.

Occurrence.—Owing to its small size and inconspicuous colouring, this
form had previously quite escaped my attention, though in reality it seems to be
rather common, at any rate off the west coast of Norway. During a 2 months’
stay last summer in that part of the country, I found this Calanoid rather abund-
antly in 3 different places, viz., at Christiansund, Aalesund, and in the Storfjord,
farther inland than the last-mentioned town. In all these places, however, it only
occurred in depths of more than 150 fathoms; and it thus appears to be a true
deepwater form. The same species was also found in 2 plankton-samples kindly
sent to me by Mr. Nordgaard, both taken from great depths, the one in the Herlé
Fjord, the other in the Oster Fjord, near Bergen. Finally, some few more or
less defective specimens of a Microcalanus (perhaps more properly referable to the
polar species) were picked out of a plankton-sample taken during the cruise of

the “Michael Sars” in the open sea between Jan Mayen and Finmark.

Page 22: Spinocalanus abyssalis, Giesbrecht.
(See Pl. XIE & Suppl. Pl. Il, fie. 2).
Spinocalanus abyssalis, Giesbrecht, Fauna & FI. Golfes Neapel. Pelagische Copepoden, p. 209,
Pl. 13, figs. 42—48, Pl. 36, fig. 49.
Syn: Spinocalanus longicornis, G. O. Sars.

(For the description of the female, see p. 22).

Description of Male. General appearance very different from that of

the female. Anterior division of body oblong oval in form, both extremities,

158 _

especially the posterior one, contracting abruptly. Front unarmed, as in the fe-
male. Urosome very slender and narrow, attaining almost half the length of the
anterior division, 2nd segment much the largest, anal segment very small, almost
obsolete. Caudal rami mobile, and generally spread to each side. Anterior an-
tennee very much shorter than in female, their length scarcely exceeding that of
the anterior division, and clothed in their proximal part with large curved, sensory
appendages. Oral parts transformed in a manner similar to that found in the
male of Paracalanus and Pseudocalanus. Natatory legs exhibiting the characteristic
armature mentioned by Dr. Giesbrecht, 2nd joint of outer ramus in 2nd to 4th
pairs provided on the hind face with an obliquely transverse row of extremely
delicate, somewhat flattened spines. Last pair of legs comparatively small and
but slightly asymmetrical, both legs biramous, with the inner ramus simple styli-
form and longer on right side, outer ramus of right leg biarticulate, of left 3-
articulate, terminal joint in both styliform.

Colour not yet ascertained. Length of the specimen examined 1.60 mm.

Remarks.—1 am now of opinion that the form recorded from Nansen’s
Polar Expedition as S. longicornis, and subsequently redescribed in the present
Account under the same name, is in reality identical with Giesbrecht’s species.
On a closer examination, I have convinced myself that the characteristic armature
of the natatory legs described and figured by Dr. Giesbrecht, is also present in
both sexes of the northern form. The transverse row of flattened spines occur-
ring on the hind face of the 2nd joint of the outer ramus is of such a delicate
nature, however, that it may easily escape attention, if the opposite face of the
joint be turned to the observer. The male, of which only a solitary specimen
has hitherto come under my notice, is so very unlike- the female, that it was
only by the dissection of the specimen that I could with perfect certainty refer it
to the present species. The most striking difference is unquestionably the dis-
proportionate length of the anterior antennz, these being scarcely longer than
the anterior division of the body, whereas in the female their lenght considerably
exceeds that of the whole body. An analogous sexual disproportion in these
antennee has also been shown by Dr. Giesbrecht, however, in a few other Calanoids
belonging to the genera Calanus and Haloptilus.

Occurrence.—The above-described male specimen was found in a plankton-
sample taken by Mr. Nordgaard in the Oster Fjord from a depth of from 400
to 600 metres, and kindly sent to me for examination. In the same sample a few
female specimens also occurred.

Distribution. —Pacific Ocean, between Lat 14° N. and 4°S., at a depth
of 1000—4000 metres (Giesbrecht); polar basin crossed by Nansen, at 2 different
Stations.

__159

Page 25. Aitideus armatus, Boeck.

Remarks.—I have recently had an opportunity, through the kindness of
Prof. Brady, of examining 2 of the Challenger specimens, from which the original
description of his &€tideus armatus was made, and cannot find any difference
whatever between them and the northern form. For this reason I must consider
Brady’s and Boeck’s species as identical, in spite of the widely-separated localities.

Occurrence—I found this form last summer not unfrequently at Aale-
sund and in the Storfjord, in depths ranging from 30 to 150 fathoms.

Distribution.—Off the Shetland Islands (Scott), Faroe Channel (Norman’s
Collection), Indian Ocean, Torres Strait, Chinese Sea, South Atlantic Ocean (Brady),
Gulf of Guinea (Scott).

Page 26. The following new genus is to be added:
AEtideopsis, G. O. Sars.

Generic Characters.—External appearance somewhat resembling that of
Aftideus, the front being produced below to a strong bifurcate rostrum. Last seg-
ment of metasome, however, well defined from the preceding one, and having the
lateral corners acutely produced. Urosome of moderate size, with the caudal rami
comparatively short; outermost seta rudimentary, appendicular bristle very small.
Anterior. antenne slender and attenuated, consisting (in female) of 24 well-defined
articulations. Posterior antenne and oral parts nearly agreeing in their structure
with those in Chiridius, the posterior maxillipeds exhibiting a similar slender form.
Legs likewise built upon the same type as in that genus.

Remarks.—This new genus is somewhat intermediate in character between
Ajtideus and Chiridius, agreeing with the former in the strongly developed, bi-
furcate rostrum, while the structure of the caudal rami and of the several
appendages resembles more that of Chiridius. The present genus differs from
both these genera in the fact that the last segment of the metasome is well defined
from the preceding one. The genus comprises as yet only a single species,

described below.

160

Atideopsis rostrata, G. O. Sars, n. sp.
(Suppl. Pi. IV & VY).

Specific Characters.—Female. Body moderately slender, with the integu-
ments of an unusually firm consistency. Anterior division, seen dorsally, oblong
oval in form, greatest width slightly exceeding '/; of the length, anterior extremity
conspicuously dilated im the oral region, and abruptly contracted in front, tip
triangularly produced, posterior extremity gradually attenuated. Cephalosome
separated above from the Ist pedigerous segment by a well-marked transverse groove,
dorsal face only slightly vaulted, lateral edges conspicuously insinuated in the middle.
Rostrum highly chitinized and pointing straight downwards, lateral spikes acutely
pointed and somewhat divergent. Last segment of metasome very short, but de-
fined in front by a well-marked curved suture, lateral corners produced to strong
mucroniform processes pointing straight backwards and extending beyond the
middle of the genital segment. Length of urosome scarcely exceeding '/; that of
the anterior division, genital segment not very large, and but slightly protuberant
below. Caudal rami about the length of the anal segment, and somewhat flat-
tened, tip obliquely rounded. Eye apparently well developed. Anterior antenne,
when reflexed, reaching about to the end of the 2nd caudal segment. Posterior
antenne with the outer ramus somewhat longer than the inner. Posterior maxil-
lipeds almost exactly as in Chiridius, the 2nd basal joint being very narrow and
elongated, whereas the terminal part is comparatively short, scarcely half as long
as this joint. Apical spine of outer ramus in 2nd to 4th pairs of legs very
strong, its outer edge densely aculeate in a pectinate manner.

Male unknown.

Colour not yet ascertained.

Length of adult female 4.40 mm.

Remarks.—This form, as stated above, somewhat recalls tideus arma-
tus by the strongly-developed, bifurcate rostrum and the acutely produced lateral
corners of the last segment of the metasome. It may, however, be at once dis-
tinguished by the far less vaulted cephalosome, and the sharply marked boundary
between the last 2 segments of the metasome. It is also of considerably larger size.

Occurrence.—Two female specimens of this form were found in a plankton-
sample taken, during the cruise of the “Michael Sars” in 1900, at Stat. 34, situated
between Jan Mayen and Finmark, the depth being recorded to be from 500 to
1000 metres.

Page 28. Chiridius armatus (Boeck).

Occurrence.—A solitary male specimen, unquestionably belonging to this
species, was found in a plankton-sample taken during the cruise of the “Michael
Sars”, at Stat. 10, east of Iceland, depth 250—400 metres.

Page 30. The following genus should be added:

Gaidius, Giesbrecht, 1895.

Syn: Chiridius, G. O. Sars (part).

‘Generic Characters.—Body comparatively more robust than in Chiridius,
with the urosome shorter in proportion to the anterior division. Front produced
below to a very small, undivided rostral projection. Last segment of metasome
wholly coalesced with the preceding one, lateral lobes obtusely rounded and each
exhibiting, somewhat outside the tip, a narrow spiniform process pointing backwards.
Caudal rami short, resembling in structure those in Chiridius. Anterior antenne
in both sexes very slender, in female 24-articulate, in male with some of the
articulations coalesced. Posterior antennz with the inner ramus somewhat longer
and narrower than in Chiridius. Oral parts almost exactly as in that genus.
Legs likewise of a very similar structure, except that in the outer ramus of Ist
pair, the spine outside the Ist joint is missing.

Remarks.— Although the differences between this genus and Chiridius
appear to be very slight, it may perhaps be advisable to retain the genus,
since there are 2 northern species that so closely agree with that first described
by Dr. Giesbrecht, that the 3 species together form a natural group. ‘The
typical species is G. pungens Giesbr. from the Pacific Ocean; the other 2 species
have been described by the present author from Nansen’s Polar Expedition as
Chiridius tenuispinus and C. brevispinus. Both these arctic species subse-
quently proved to be referable to the Norwegian fauna. The female of the first-
named species has already been described in the present Account, and it only
remains here to describe the hitherto unknown male of this form. The 2nd species

is now for the first time added to the Norwegian fauna.

22 — Crustacea.

162

Gaidius tenuispinus, G. O. Sars.
(See Pl. XVIII & Suppl. Pl. VI, fig. 1).

Chiridius tenuispinus, G. O. Sars, Crustacea of the Norw. North Polar Expedition, p. 67, Pl. XVIII.
(For the description of the female, see p. 30).

Description of the Male.—Anterior division of body, seen dorsally, oval
in form, somewhat attenuated anteriorly, with the greatest width occurring consi-
derably behind the middle. Lateral processes of last segment of metasome well
marked, and of the same appearance as in the female. Urosome, as usual, much
narrower, and composed of 5 segments, the last of which, however, is very small,
almost obsolete. Anterior antenne of about the same relative length as in female,
but transformed in the usual manner, their proximal part being rather dilated, and
clothed in front with large curved sensory appendages, terminal part very slender,
and forming with the proximal one a somewhat angular curve. First pair of legs
with the 1st joint of the outer ramus distinctly separated from the 2nd. Last pair of
legs comparatively large, and somewhat resembling in structure those in the male
of Chiridius armatus, both legs provided with a rudimentary inner ramus, that
of right leg pronouncedly club-shaped, that of left much narrower; outer ramus
of right leg biarticulate, with the proximal joint rather large and curved, distal
joint very narrow, and forming a small rounded lobule inside, beyond the middle;
that of left leg 3-articulate, last joint spiniform.

Length of the specimen examined about 2 mm.

Remarks.—It will be seen from the above short description, that the sexual
differences in the present form do not materially differ from those found in the
genus Chiridius, and the last pair of legs in the male even bears a very close
resemblance to those in the male of Chiridius armatus.

Occurrence.

The above-described specimen was found in the same sample
(Stat. 34) in which Atideopsis armata occurred, and could at once be recognized
as the male of the present species by the slender spiniform processes issuing
from the last segment of the metasome.

Gaidius brevispinus, G. O. Sars.
i (Suppl. Pl. VI, fig. 2).
Chiridius brevispinus, C. O. Sars, Crustacea of the Norw. North Polar Expedition, p. 68, Pl. XIX.

Specific Characters.—Female. Body comparatively robust, with the anterior
division rather massive and, seen dorsally, oblong oval in form; anterior extremity

somewhat contracted near the tip, which appears obtusely truncated, posterior _

163 —

extremity only shghtly attenuated. Rostral prominence exactly as in G. tenwi-
spinus, forming a very smal] conical projection, Lateral lobes of last segment of
metasome broadly rounded, spiniform process outside the tip extremely small.
Urosome scarcely attaining '/; of the length of the anterior division; caudal rami
comparatively very short and somewhat divergent. Anterior antennze slender and
elongated, reaching, when reflexed, as far as the tip of the caudal rami. Posterior
antenne and oral parts almost exactly as in G. fenwispinus. First pair of legs
with the 1st joint of the outer ramus well defined, though, as in G. tenwispinus,
without any trace of a spine outside; inner ramus of 2nd pair distinctly biarticulate.

Male unknown.

Colour not yet ascertained.

Length of adult female 4.80 mm.

Remarks.—This form is undoubtedly very closely allied to G. tenwispinus,
though easily distinguishable by its much larger size and somewhat more robust
form of body, the more elongated anterior antennse, and the small size of the
spiniform processes issuing from the last segment of the metasome.

Occurrence.—A solitary but well-preserved female specimen of this Arctic
form was found in the same sample (Stat. 34), m which the male of G. tenwi-
spinus occurred.

Distribution.—Polar basin crossed by Nansen, at 6 different Stations (the

present author); Fiiroe Channel (Norman’s Collection).

Page 32. Undinopsis Bradyi, G. O. Sars.

Remarks.—During the past summer I have found tbis form very plentiful
in one place near Aalesund, just at the bottom of a steep incline, on a sandy
bottom. Male specimens were by no means rare, and on a renewed examination
of the latter, I found that the right last leg is generally wholly absent. In some
few specimens from the same locality, otherwise indistinguishable from the others,
these legs, however, exhibited exactly the appearance figured on Pl. XIX, a distinct

rudiment of the right leg being present.

Page 39. Eucheta norvegica, Boeck.

Distribution.—Scottish coast (Scott).

Page 42. Eucheeta barbata, Brady.

Distribution.—Gulf of Guinea (Scott).

164

Page 47. Xanthocalanus borealis, G. O. Sars.

Distribution.—EKast of the Shetland Islands (Scott).

Page 53. Amallophora brevicornis, G. O. Sars.

Remarks.—The hitherto unknown male of this species has recently been
described by Th. Scott, and the correctness of my opinion in considering this
form to be a true Amallophora, is fully confirmed by the structure of the last
pair of legs, which are built upon the very same type as in dA. magna Scott.

Distribution.—Kast of the Shetland Islands (Scott).

Page 66. Parastephos pallidus, G. O. Sars.

Distribution.—1 have recently received from Th. Scott an adult male

specimen and an immature female of this form, taken by him off the Scottish coast.

Page.
PUCURIG eee cdak RIO Oe 148
JOMnMORENS Sow poe a oO hon ens 149
ONGICUN Soo Pee ED RES 150
WUSCHUM ALA \ 3. cveha sci 152
LORGUPCMIR: 1. . = aa. wales 149
PCI UOEE hs cutis tote teh vastaets 147
Acrocalanus: «a. «eee eves 6
Amallophora ........0..- 50
brevicornis ........ 53, 164
MVAGIG aiicte cfarictein eet: 5]
LVI CAMay.ventemuetacrena eae 51
Amphascandria ......... 7
AROMALOCETG sjannaaas ee 138
SRALCRSONU a |, gee ae On 139
Arietellida 4. vs sree hae 123
Auieteliltis mcm rrniore 124, 127
/ Nee HOMME S oo oooGnS Ii 12H
Boeckellan «ic cc. b ec scceaee 74
Braciyacaus sya)... oteseare eee dl
UETNAGUS penelle setae tats 32) 33
TSG QEAS ss cis cela as 35
GKEULCOTNISs = «2 a)... ee 35
COONS saw ape ost es 8
COlAnoidas sa Mokhen Le 4
@alamopiay ja ascdstice soc: 138
CGlANUS, Jobase od he eee: 8
Ollaicnl Soc ocnemopeie dpc 20
finmarchicus........ 95) 12
helgolandicus ......... 11
PCR GOV CUS 0 <.<.2 00 3 12
NOM OVS Reegereaonarpenstoneteret te 112
MEL AO TUS As ayes a d sethehcren sre ots 12
PALVUS! ciate sic. eyelet clenena cress 17
[NVEACNETOS, solv cacao one 17
qvinqveannulatus ... 9, 10
LUE DINALUSIa ie tee eee 98

INDEX.

Page.
Callocalamtistrrer crs alsin 16
Candacespren. deci. re 133
ALVIN ALA oseye tess arate tana 135
CURL napa craverstoraialeie ohelete 136
IONE DIMOKES cago geg0gueK0c 135
CllonverhieN sas a oan ooo 0C 134
lonpumiamna ccs os os stator 135
MOLVEL1CA) myetele<) 2s soe LB
PeCtiMataywaysyins 135, 136
Caondacian ae aun rte 133
OV MAU cioro raver oislereeres 135
MOV VCQUCH pias oi0t 3 eae 134
Candatnde cis sawouee 132
Pamnaeid ae erate sistas teense 133
CHUPAAUB oars 1S ra 27
ONIN GUUS es otal 27, 29, 161
DEC WAS UALS! perder ee 162
QDLUSUTONS) <3 aso aks tee 29
BOPP acictarnacke rt set en 27
CEMUMIS PLUS aye stories 30
Centropagide2...osk. «00s 73
Centropages. .~ » saleuan ee 74
ROPUCUB occa alec. oye ees Fe 76
ADUCUS shia a. o/alo, ePSRI ASE 75
Cetochulasine vaccinate 8
heloolandicus, ...\. 6s). st 11
septentrionalis ........ 9
ClaMsia capresso ek m ate 19
SIGMVERKIAY 5 Sas so.50n0 20, 21
Clausocalanine.......... 19
Clausocalanustyy 1 eae 19
(Copal daoseoopsadobe 73
Ctenocalanusy.-y-n-1rre er 19
Cyclops
Jacinwlabusy aloes 101

Lon eTCORNIS hy. te wee Ss}

Page.
DALTONS ae eet eee 38
Cyclopsina
JXOSHEE NING: Ae einenioin Faas 6.0 107
lacimimlatayseeee iste 100, 101
dD GIS HS () Peer PERS c, ofF, 5. 57
197009 PRES St 5S 58
WOUTAWE manomonsaccoc 59
Diapionide) oc sos ene: 83
Draplomus sie sce 84
abdomaumnalisnn .crechieere: 115
bacilifen os. 5 = wars ee 88
COSLOGE ote sa oneahenolee 8); 987
UANUOGHAIIS> Gb b00a000¢ 87
GF ACIS > ows oS AIS 8 92
GT ACUOIOES on 3) Sei ss 94
NamatuUs .rcyeu a atetee eye 87
LACNLOLIS ee ee 91
LIUGEDSi-a ance a eee 90
longicaudatus...... Si, ke!
MAOMNIFINEES ce rocogeocuc 83
PO UUSTISE fecha) a ber erie. eee 88
salilens) ss4-e ects n eee 106
VWiVGRUROOGN ci5.n e066 056 92
WIAs ey saicic ceree aa 148
GMKCINORMS! concacosoec 152
LON SITET peal estes 149
Dissetaltt se saeuueceeces 73
Drepanopusm anced 19
ID HKONT oe acoso Sa baci 76
LIV QTUOT MCN s5.6.6.6.6 oon oo a 13
i WeAalanusi erie yet eae 14
LIVGUIO ae acca beoleiosuc 37
EIGIMENE) 6 ooo ouobE Oo 27, 28
DARDGT Oia om Ske 41, 163
CABIN GGA ays) ere ciecare ateraiees 38
QLACKAVIS Sire oho oa ONS 40)

Page

MIMO, Gano ganophonod 39
NOYVEPICA...... 38, 40, 163
Prestandres .2........ 38
MGHOCUMG TS ae ajar te 36
IDMOEMAEANNIED sagangenoo5ade 37
ETUY LCTAOV Gs) atone iG ls
AERIS! Sassc) teers fetes cust 102
Clauss saree eer acienierinn 100
PT ACTIISE Rent eerie eee 102
INNIFEBACIO) Go coonodaucced 102
WirUndovdesy., ters. 102
lacimullatay erent ere 100
UG CUSTTIS rrrmeecemn eee. ore 103
DELON G?. cred ANTe rena eesti 100
GQidius ha oh Pe eee oe 161
DRECISDINUS Sere ree 162
PUNLENS Reus 161
CTMUISDINUS Gy ene Sane 162
Gilauceagenici rer eer 84
LUDENS Receieee aeeetete 85
Elahitem Oras Oo, Sri
LON PU CORNISH errr 97
VAI ODUUUS 4 carci non yes 120
CULUFT ONS wi ceyy soled ee 122
longtcornises. ons soe 121
Hemicalanus ....... 120, 121
AOMBUTROMS soogou5d0066 122
TOMPICOMNIS: 2h <5 5 wis es 121
Spiniironse seeps ee 122, 123
iElemupontellansen).0s eee 141
Heterarthrandrie ....... 72
Heterochcetayasacie soe ae 117
COMMIS, Soscodasonor 118
MOTVCL ICA ween sre aiereeapee 118
eVOMMEME, o5oc coede cao s 120
S]OUAVETROMIS 5 gas qoldaous 120
NACLEVOCODC ey aep buy. Perete e 104
MMlgbIES Yio omen on bee 106
appendiculata ......... 109
DOr ealissnarita cnt le 107
MONLAN AW. tear n te eee 106
EODUSKA wey aaeore 106, 107
SCLICMS. «Ruz evs Sate evs 106, 107
Wieissmanni 2. .- 107, 108
Heterorhabdide ......... 117
eter Ov Na0dUs. 758 eee LAR
MORUEQUCUB tess soc; 45.03 118
Ichthyophorba .......... 74
ANOUSLALAR Es eee = «tes 76
denticornmismeys aes .e ine 75
IVATMIAAD-Reeiclenshercksnchenstats 76
if phi oniyexdemyasverscakekeactrnes 133

166

Page.

IRAE SUIS aeceone ona creme chee 138
splendidus ....... 139, 140
FESUO Sapte erator cia e snore 78
IEXOIMAMEIT’ Goon moeanGooe 79
UWA SA Bo Sar OR Oe 79
Isochsetawmeemres sire ec 12
WSO CRONURUU erie ees: 56
IHG, Gigs ooo OOD 138
JEGWGINOTT 6 onpa5boane oe 141
WWQUIGEHOM0s 6000 Go5G006 142
Tamme linn Odi aeyerctere eet lefer sie 96
Wewekamtiimaemereyee tacos « 73
TN NOCOONUS ttette terete el = 80
Emini Goog0dodc 81, 82
TMG UPU BS acc.00 pBCOROS 81
SIMENISI Sasol t whsy ocho ete 81
IL @FOMIOWMEEK 5 Coccoooeacss 49
IGNORE) Gcaoanoaccouoc 73
ID OVC HEMMINGS A "5 ob aco oOo. 73
lbw, cisco odo oO n0.c 19
ACHP CSepssdes servo 20521
IMG GyTO CELA cca tonesomevenenne 14
iMeiridig Arcee ace 110
RIMMENE) aiowa.c cao aoc 112, 113
InN oo aaamanaso.c 5 113
LOWG Gisspocrusqexcrensr ihe e ROT 112
LUCEN Shins steven cnete a orecrereere 113
WARUMIINS sonanadodosac 110
Microcalanus........ 20, 155
PIUSTVUS soc Soa) citend autpbenete 156
yA eae oogoe MadoT 20
MSO pElaeracts estas 127, 130
Misophriide ... 127, 129, 130
WIG} OEAIS Soy Aa oo o.0 0 6 61
OYRATIS( pe pewcusgenaecrete shoe 62
Monoculus
CAStOM: sve ieistenctoy vederonenaene 85
fnmanrchieuse-i eee )
IMONOPSiiieskegkoouaeoe 138
WiGramvormilley ss oanchuados 73
Osphranticumige cryrteieen 74
Poracalantd@. 066.008 «3 16
PAPACQlanUsina ss sonore 17
ACUICATIS! Seyi sieceveveusiore We 17
hibermicusi.. 4. +. cerier 113
DOUUUS aetnten teres 17, 154
iParacakul veered ese ee 147
Paradiaptomus tiie 84
ELaramisopliig 4. 2seaee 127
CLUARE a. omicine hen AE 128
PORApONtEUG cil) aee ieee 144
OVCWCOTNIS oe +o Sieclosites 145

Page.

Parapontelltdee © inx' see 143
Parapontellingz ......... 144
Parastephos> sak ake 85
POU TAUB ers oak als ates 65, 164
Phaenmairs cict.cnlve sieve 43, 44
Spinibevales ciao se eects 45
PRAHA Tier ee ee 42
Pleuromamma.........4+ 114
VOOUSUL sl topnaterenaereele ae 115
IMME Soa ooaaddoocc 114
MIRO sop ooeodooodonc 115
MONON 5G q0doKon00¢ 115
iRoppellar civics 73
Pontella 2. .cecm eer 138, 141
Hu geniee. <5 .50 ait. 3 eee 139
helgolandica...... 142, 143
Wollaston 2a -o5 ee 142
PGDCCUAAC 5.5, Hers 21g 5.4 ROE 137
iPomtellinaieee ener 138, 144
DEE CONIM Seeie tere 145
Pontellopsis = 4-14 iekke 138
Rontiaee seco ooeoe 138, 140
lennon S666. 950000¢ 139
Pseudocalanide ......... 19
Pseudocalanus .......- 18S 24
EAMONN 45 goo oc 25. 32
elongatus ........- 20, 154
QUOCUISY vic ciccx Bu eta 154
TEN OMPBINBigdo o a0 cos co'S 20
[DARA ooo Bano Aco 20
Pseudocyclopia ........+. 70
Caudatara van iste nee 70
CLASSICOTNIS pp eres 70
AYU O10 op suspevoncncseny eee 70
SLEPROUCE ota areas 71
Pseudocyclopid@ ......... 129
Pseudocyclopiide ........ 69
‘Psendocyclops:.. =. Wsaret 130
ODUUSCIUS > «5 15504 ee 131
Pseudodiaptomide ....... 73
Pseudodiaptomus ........ 73
Pseudophaénna .......4- 43
LYPACO 5. cn ave exonet st Aenea 44
Bhincalanus:.... yscew sae 14
COLMULUS aie aeiei evra 15
PISAS core 154
WASULUS:, was ss 6 0 15, 154
Scaphocalanus vars -setieier: 50
ACLOCEPNAlUs verre 51
Scolecithricella .......... 54
WNVILOL ..«:s Bais eeise tee It 55

167

Page Page. Page.

Seoleemthrmx... 495900, 54, 58°} oStephide. ov. 22 oe ees: 60) io Dharybide smc. «3 alee: 66
SUVS AES! vets Fonte wees oi. 2 HOt TSLEDROSEM a otnene as(< 3 cus cas GL. |) Dharybisinn. «eee. 67
ReWICORMIS <acpaieyc==)<'-0¢ 53 ABYC OMA yensyerscase, oo ls o8ee 62 macrophthalma ........ 68
CUA, coscaosooeoooe 5 Payil MUS Beveenyen eis siassarsstchty sas 63=|) Tortanide ss. hytr eee ere 73
Wax ee rents easeape era chins .8: 06 57 DL TAGNOT ATES 5 CRO SOIR G2) | Dortanusiae sae sect Craaiaer 73
Cem babar sracsite es ta 2, sues 5d TAN OWA Ao DOO Ome 6277) Dy phlocalanus. ene 64
TMM Vette vey areata sp 8/ ew sacs 55 IS COLLIN ese ae Nee ets 63 SYLACOK” ..:). svete eee 64
HUN STNCA s,s vic: oieeieim wees DO UCIONO wins, is Senior o lta as SG |p Uindinas.* ceo eee Sh)
POMSUEUCA ea tcaen oe ayes D5 (CIE IGT aaa scr LOOP TOM Undinopsis’...40 e dl
HOMONPOS < cheats sno «48s ats 55 fimunarChiGaey. ss. scsae « Shei SOY «3 acters cee 32, 163
aMENHoAOP UES e An enc oe ciclo 55 AERIS eat st http See 102 SOMOUTSY oi .s santero 34
[G01 000) PAR el tr ROR ERE 5d LORGUCORNTS 2 5s sna Raye Of |) Manthocalanus .. 22 32. 5ee 45
POE OL VITAL Aare ars tciwwi abel eae 55 ELON feces cre «1 seed 100, 102 GOR EUNST pass s seta 46, 164
PV PUNCH ec) cic el fy vie ehevane 5S) Bemonelllary ios... 210s 5! ots 99 DL GDINGUUS 5.0%. cere 48
temuisernatals: sie isn 5d ASAITNIS estes egane ciche Suelo MODE | eauri deren re .1<.5 eke epee 23
VALGALEL scueletarslts sveuevels! oy 55 Claire y sar seer seeps COLO EP DA eVIETS cite CIRO and 24
Scottrampmcmerriene ce one 125 intermedia....... 103, 104 CHTOOKKMS po 5gopanet 2a, 159
SCOUEIIOM fonce Packie iha si bss 124 lacimulatale evar oxcak cya LOOM" Athdeapsistarci ase «oc 159
URE GUICOR NUS, acs vote. Sais 125 TV CHSHEIS see ccs: as cheresses 103 MOSUL Oa cet cic teitey sche Te 160
SUMOCMIGNUS 5. «nn tes ss Be lM O VUE hare rata ysns fetus cas 9b, |), -Alltidsamge se fora spares as ay stews 24
UU SEALS 2.) i052 creas QBs shone eMOnibeSane eran were rele WoT) ADIMGMOS 408 c0b acco po UNk 24

LOMATCORMIS eye rr erent 22) MEMOLO plage ae 96

ST OF PLATES.

The Plates have been marked as far as possible in accordance with those belonging

to the 3 previous Volumes (Amphipoda, Isopoda,

Cumacea).

The following are the chief signs, with their significance:

female; male: (. cephalosome: FR. rostrum; Urs. urosome with the caudal rami;
I : :

gen. S. genital segment of female; O. eye: a.! anterior antenna; @.* posterior antenna; 0”. area

oral area; L, anterior lip; M. mandible; m. maxilla; mp.' anterior maxilliped; mp.* posterior maxil-

liped; p.t—p.° legs of Ist to 5th pairs.
Pia:
Calanus finmarechicus (Gunner), female.

124K, JO
Calanus finmarehicus; female, (continued).

Pie ihe
Calanus finmarchicus, adult male.

lek, JW
Calanus helgolandicus (Claus); female & male.

Pe
Calanus hyperboreus, Kroyer: female & male.

le Wale
Rhinealanus nasutus, Giesbrecht; female. |

PS Vale
Rhinealanus nasutus; female (continued).

Pi. Vil.
Paracalanus parvus (Claus); female.

IE 1D:
Paracalanus parvus; male and female (con-
tinued).
Pexe

Pseudocalanus elongatus, Boeck; female.

ul, Dah,
Pseudoealanus elongatus, male & female (con-
tinued).

1g D0
Spinoealanus abyssalis, Giesbrecht; female.
(See Suppl., p. 157.)

PS Xue
Atideus armatus, Boeck, female & male.

EN SXLVe
Atideus armatus; male & female (continued).

ID AY
Chiridius armatus (Boeck); female & male.

Ply xeval:
Chiridius armatus; female & male (continued).

BE XV
Chiridius obtusifrons, G. O. Sars: female &
male.
1B, walnuts

Gaidius tenuispinus, G. O. Sars; female. (See
Suppl., p. 162.)

1S RODS
Undinopsis Bradyi, G. 0. Sars; female & male.

IDG 9.0:¢
Undinopsis Bradyi; female (continued).

IAL, d-Ordls
Undinopsis similis, G. 0. Sars; female & male.

Pl, XX,
Bryaxis brevicornis, Boeck; female.

Pl, XXIUI.
Bryaxis brevicornis; female (continued).

Pl. XXIV.
Eucheta norvegica, Boeck; female.

Pl. XXY.
Eucheta norvegica; female (continued).

PLP XVI.
Eucheta norvegica, Boeck; adult male.

PP OXeXS VALI,
Eucheta glacialis, Hansen; female & male.

Pl. XXVIII.
Eucheta barbata, Brady; female & male.

Pl, XXIX.
Pseudophaénna typieca, G. O. Sars: female &
male.

Pl. XXX,
Pseudophaeénna typica; female (continued).

Peo,
Xanthocalanus borealis, G. 0.
& male.

Sars; female

Pik XOXO,
Xanthocalanus borealis; female (continued).

12aly 9:0:0:G NE
Xanthoealanus propinqvus, G. O. Sars; female
& male,

Pl. XXXIV.

Amallophora magna, Scott; female & male.
TPP PXOXOXGY 7:

Amallophora magna; female (continued).
PR eeNENONGV IE

Amallophora brevicornis, G. 0. Sars; female.

Tee PNOXENGV ALE
Seolecithricella minor (Brady); female & male.

IDE LO: OQ HIE
Seolecithricella minor; female (continued).
PP XOX.
Diaixis hibernica (Scott); female & male.
1215 abe
Diaixis hibernica; female (continued).

23 — Crustacea.

Pie xcile
Stephos lamellatus, G. O. Sars; female & male.

Pi exente
Stephos lamellatus; female (continued).

IW SOUT
Stephos Seotti, G. O. Sars; female & male.

Pl. XLIV.
Parastephos pallidus, G. 0. Sars; male.

1.4 BAe
Tharybis macrophthalma, G. O. Sars: female
& male.
Ply XLV.

Tharybis macrophthalma; female (continued).

Pl. XLVIL.
Pseudocyelopia stephoides, Thompson; female
& male.

Lely bAVIBUE,
Pseudocycelopia stephoides; female (continued).
Bi XauX.
Centropages typicus, Kréyer; female.
Pile ls
Centropages typicus; female (continued).

Peis
Centropages typicus, Kroyer; adult male.

Pl. LI.
Centropages hamatus (Lilljeborg); female &
male.
Pl. LIM.

Isias clavipes, Boeck; female & male.

Pie
Isias elavipes; female (continued).

ee lnve
Limnocalanus macrurus, G. O. Sars; female
& male,
12, JUNAL

Limnoecalanus macrurus; female (continued).

Jel JUN Awe
Diaptomus castor (Jurine); female & male.

IPE AG \yAuot
Diaptomus castor; female & male (continued).

IPE exe
Diaptomus denticornis, Wierzejski; female &
male.

ue

PA aXe
Diaptomus bacillifer, Koelbel; female & male.

IPL, JOMNOE
Diaptomus laticeps, G. O. Sars; female & male.

excl
Diaptomus laciniatus, Lilljeborg; female & male.

Ea elite
Diaptomus gracilis, G. O. Sars: female & male.

Pl. LXIV.
Diaptomus graciloides, Lilljeborg; female &
male.
Pl. LXV.

Temora longicornis (Miiller); female & male.

Pl. LXVI.
Temora longicornis; female (continued).

PASI XoVanl
Eurytemora velox (Lilljeborg); female & male.

PA pxeValeil:
Eurytemora velox; female (continued).

PP XE
Eurytemora hirundoides (Nordqvist); female
& male.

1 DXEXe
Eurytemora lacustris,.Poppe; female & male.

Pl. LXXI.
Heterocope saliens (Lilljeborg); female & male.

IPS Lxexaile
Heterocope saliens; female (continued).

1k 1.0: 00k
Heterocope borealis (Fischer); female & male.

12S TROY,
Heterocope appendiculata, G. 0. Sars; female
& male.

PS XeXeVe
Metridia longa (Lubbock); female & male.

PS MUPNOXGV iT:
Metridia longa; female (continued).

Pl. KXXVII.
Metridia lucens, Boeck; female & male.

Pl. LXXVIU.
Pleuromamma robusta (Dahl); female & male.

Pl) GXeXEX,
Pleuromamma robusta; female (continued).

Pl. LUXXX.
Heterorhabdus norvegicus (Boeck); female &
male.
Pl. UXXXI.

Heterorhabdus norvegicus; female (contin.)

Pl. LXXXII.
Haloptilus longicornis (Claus); female.

Pl, LXXXIHI.
1. Haloptilus longicornis; female (continued).
2. Haloptilus acutifrons, Giesbrecht; female.

Pl. LXXXIV.
Scottula ineqvicornis, G. O. Sars; female.

Pl. LXXXYV.
Scottula ineqvicornis; male & female (con-
tinued).

Pl. LXXXVI.
Paramisophria cluthe, Scott; female & male.

IP pNexexovalile
Paramisophria cluthe; female (continued).

Pl. LXXXVIII.
Pseudocyclops obtusatus, Brady; female &
male.

Pl. LUXXXIX.
Candacia norvegica (Boeck); female.

PA eC:
Candacia norvegica; male & female (contin.)

Plex
Candacia armata (Boeck); female & male.

mbes ore
Anomalocera Patersoni, Templt.; female.

1a NC OLOoe
Anomalocera Patersoni; female (continued).

IP eXC LV.
Anomalocera Patersoni, Templt.; adult male.

PIR OXCVE
Labidocera Wollastoni (Lubbock); female &
male.
1BlG MON AL

Labidocera Wollastoni; female & male (con-
tinued).

fal

Pl. XCVIL.
Parapontella brevicornis (Lubbock); female
& male.
Je, SON AODL
Parapontella brevicornis; female & male (con-
tinued).
Pl. XCIX.

Acartia longiremis (Lilljeborg); female.

ING Go
Acartia longiremis; male & female (continued).

IDL, Cl
Acartia Clausi, Giesbrecht; female & male.

1PAl, COMM.
Acartia discaudata, Giesbrecht; female & male.

Suppl. Pl. I.
Pseudoealanus gracilis, G. O. Sars; female &
male.

Suppl. Pl. I.

Microcalanus pusillus, G. O. Sars; female.

Suppl. Pl. III.
Microcalanus pusillus; male.

Ie
2. Spinocalanus abyssalis, Giesbrecht; adult
male.

Suppl. Pl. IV.
Atideopsis rostrata, G. O. Sars; female.

Supp]. Pl. V.
Atideopsis rostrata; female (continued).

Suppl. Pl. VI.
1. Gaidius tenuispinus, G. O. Sars; adult male.
1. Gaidius brevispinus, G. O. Sars; female.

PI. XCII

Copepoda
Calanorda

Pontellides

= > Ue. 4 ; =
See N=

er

a oS Sear

Sau See ——

———— AR : —
a Me vw a 2 hs
SSS SON SNAG
AR: Wa i = Rees = f
Se NEES = ns aoe % ae penne SN
ba NES 5 == Seinen LI el
Se ae : as? = TIT S

Tryktiden private Opmaaling, Chra

6.0. Sars auto gr.

Fattersoni, Templt.
continued ,

(

Anomalocera

PN

iebew

evil Oe

c d
aad De a

Pontellidas

et enn Wire eta %
LW eee

ams oD

Sere Sees

cea

Sa SSS
(tS ——
Co ee
SS = <——.

Sea

Tryktiden private Opmaaling Chra

Fattersoni, Templt.
male}

|

Anomalocera_

6.0.Sars autogr.

Calanorda. PL XCV

Copepoda

Pontellides

y

at

<a

He =
TATE TNS

Tryktiden private Opmaaling,Chra

( Lubbock!)

Wollastone

G.0. Sars autogr.

Labidocera

PL XCVI

pepoda

oo

Tryktiden private Opmaaling,Chra

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AN ACCOUNT

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_ WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

Pe eG. Oo. SARS. :

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© COPEPODA:: a
7. GALANOIDA

Pe Eee Ri ae PARTS XIII & XIV 7
-. PARAPONTELLIDA, ACARTID/, SUPPLEMENT

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WITH 12 AUTOGRAPHIC PLATES

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Beg BERGEN | r
- PUBLISHED BY THE BERGEN MUSEUM
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ALB. CAMMERMEYER’S FORLAG, CHRISTIANIA
1903 |

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AN ACCOUNT

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AN ACCOUNT

OF DWE

CRUSTACEA

OF

NORWAY

WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES

BY

G. O. SARS

PROFESSOR OF ZOOLOGY AT THE UNIVERSITY OF CHRISTIANIA

VOL. IV.

mol POD x

CALANOIDA

WITH 108 AUTOGRAPHIC PLATES

BERG HIN
RUBiots ak De BY THE BERG HN MUSE ve

SOLD BY
ALB. CAMMERMEYER'S FORLAG, CHRISTIANIA
1903

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'

BERGEN. JOHN GRIEG.

PREFACE.

The present Volume deals with one of the great divisions of the ex-
tensive order, Copepoda, viz., that of the Calanoida, which of late has attracted
the special interest of biologists, on account of the enormous numbers in which
some of the species are sometimes found to appear, forming, as they do, a very
essential part of the so-called Zod-plankton. As not only the amount of the
plankton, but also its quality is of great significance in determining the nutritive
value of the water both in the sea and in lakes, a thorough knowledge of the
organisms composing it may be said to be quite indispensable. It is now gener-
ally admitted that Copepoda of the Calanoid group form an essential part of the
nourishment of several of our common food-fishes, either in the adult state, or
at any rate in the earlier periods of their life; and the investigation of: these
little creatures must therefore be regarded as intimately connected with that of
the fisheries, whether in the sea or in lakes.

The present Volume, which gives full diagnoses and figures of all Nor-
wegian Calanoids, both marine and fresh-water, known at present, may thus, I
hope, be of essential use to those who are studying our fisheries and the biological
conditions connected therewith.

In order to make the determination of the species as easy as possible,
I have given, besides anatomical analyses, carefully drawn habitus-figures of all,
in most cases both a dorsal and a lateral view, and as a rule of both sexes.
The detail figures, unlike those in Dr. Giesbrecht’s work, are always arranged in
such a manner, that they can at once be referred to their respective species.

An objection may perhaps be urged against the practical arrangement of
the present Volume, as also of the 3 preceding Volumes, viz., that no analytical
tables are given. In my opinion, however, the practical value of such tables,
especially when they comprise.a great number of different forms requiring a more

or less complicated arrangement, has been much overestimated. I think that the

VI
student, instead of labouring through such a complicated table, will in most cases
prefer the much more simple and direct method of determination by comparing
his specimen with the figures, and, if still in doubt, consulting the short diagnoses
given of the respective families, genera and species.

In the elaboration of this Volume, I have been assisted by several di-
stinguished naturalists both in my own country and abroad; and I desire here to
tender them my best thanks. Among foreign naturalists, my thanks are due to
Canon A. M. Norman, Mr. Th. Scott, Prof. Brady and Prof. Cleve, for sending me
interesting specimens. I am also greatly indebted to the Zoological Station at
Naples for a very interesting series of plankton-samples, which have been of great
use to me in comparing the Mediterranean species with those of the northern
seas. The Norwegian naturalists to whom I wish to offer my hearty thanks are
Mr. O. Nordgaard, director of the Biological Station in Bergen, and Dr. J. Hjort,
director of the Norwegian marine fisheries. To the latter gentleman I am especi-
ally indebted for the opportunity he gave me of examining the numerous plankton-
samples taken during the cruise of the “Michael Sars” in different parts of the
Norwegian Sea. A most important addition to the Calanoid fauna of Norway
has thereby been gained, as will be shown in the course of the account here
given. Finally, I beg to thank the direction of the Bergen Museum for the read-
iness with which it has undertaken the continued publication of the present ex-

tensive work.

G. O. Sars.

ERRATUM.

Page 114, line 10; for ,It was subsequently recorded,“ read ,It had been previously
recorded,“

» 4

er

S59.

-

PL XCVIL

Copepoda
Catanorda

Parapontellide.

v1

| sss

rT

Trykriden private Opmaaling, Chra
Parapontella brevicornis (Lubbock |

G.0.Sars autogr

Copepoda
Caranorda

Parapontellida.

E Tryktiden private Opmaaling Chra
Parapontella brevicornis (Lubbock }
(continued)

G.0 Sars autogr

*)

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Calanoida

Tryktiden private Opmaaling Chra

GO Sars autogr

Acartia longiremis (Lilljeborg)

Calanotda Py &

Copepoda

Acartida.

Veer

—

AES Se

f Vai

=<

—

! 7

Tryktiden private Opmaaling, Chra

Acartia longiremis (Lilljeborg)

G.0. Sars autogr

(continued)

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SS

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6.0. Sars autogr.

Tryktiden private Opmaaling,Chra

Acartia Clausi, Giesbrecht.

Copepoda

Acartiide. Calanorda | Pri

lh
AA brs iL

ALE

Trykt iden private Opmaaling,Chra
GO Sars autogr.

Acartia discaudata Giesbrecht.

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Pseudocalanide. — Calanorida Suppl. PL. I

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Pseudocalanus gracilis , G.

Copepoda

Pseudocalanidag. Calanorda Suppl. PI. I

Po a SE ne a oe
G G Sars WO g Trykriden private Qomaaling Chra
OAaTS aurogr Y¥KO: den priveté Upmaaiing

Microcalanus pusillus , 5.0. Sars.
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eh
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epoda

P
Calanorda

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Pseudocalanida@.

i}

Trvkti den private Opmaaling,Chra

G.0.Sars.

neu

pusill

1. Microcalanus

G.0.Sars autogr

(continued) _
(2. Spinocalanus abyssalis, Giesbrecht

(male)

Copepoda

Calanorda

FEtideide.

a

7 qj
“4 eb

ae

=
: ij

Tryktiden private Opmaaling Chra

0 Sars autogr

G

rostrata ,G.0.Sars.

Atideopsis

#

+

a4
2

Copepoda
Suppl. PL.

Atideide.

Calanorda

Trykriden private Opmaaling Chra

rostrata ,G.0.Sars.

(continued)

Atideopsis

G0 Sars autogr

Calanoida Suppl. PI. VI.

Copepoda

Ftideide.

“fy
Lok >
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a 2S

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aes SS Dee
rnc go

Tryktiden private Opmaaling, Chra

ae a \\ \ ae
ARE i BN 2»
ey /. toe : ft any
es {i NN) 2) Peete

roe ae

GO oars:
(male)

Tenuispinus
2.Gaidius brevispinus , G.0.Sars.

1.Gaidius

G.0. Sars autogr

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ete a a eet MIONE! S49 appre igl snes) HO \ieletedern at ty

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- wistereariene ete erent nn wpe a Seen Ryan ienes oe ;

ee Soo traaenteanoneraaman See

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ste cemeenonied nen reere oe : fatinneilesenieaunet tn ttnfnsininananoe oe ieessertnerh aan
iebeianras adel ayesagenarayeeeyselaeataribaascansisi ay tent Tatts

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