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THE DANISH

INGOLF-EXPEDITION.

VOL. Ill, PART 4

CONTENTS:

CARL WITH: COPEPODA. I.

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PUBLISHED AT THE COST OF THE GOVERNMENT

THE DIRECTION OK THE ZOOLOGICAL MUSEUM OF THE UNIVERSITY.

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COPENHAGEN.

H. HAGERUP.

PRINTED BY BIANCO LUNO.
I9'5-

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THE DANISH INGOLF-EXPEDITION.

VOLUME III.

4.

COPEPODA I.

CALANOIDA AMPHASCANDRIA.

BY

CARL ^ITH.

WITH 8 PLATES, 422 TEXTFIGURES, i CHART AND A LIST OF THE STATIONS.

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COPENHAGEN.

PRINTED BY BIANCO LUNO.
1915-

Ready from the Press December the nth 1915.

CONTENTS

Introduction

On the material

On the Uterature 3

On systematic characters 4

On postlarval development 7

On nomenclature and abbreviations 7

On the description of species 8

On variation and parasites 9

Calanidae 10

Calanus carin atus Kr 11

— cristatus Kr 11

1. Calanus finmarchicus Gun 10

2. — hyperboreus Kr 30

Macrocalanus G. O. Sars 36

3. Macrocalanus princeps Brady 37

Megacalanus Wolf 40

4. Megacalanus princeps Wolf 41

Eucalanidae 44

5. Rhincalanus nasutus Giesbr 44

6. Eucalanus elongatus Dana 48

7. — attenuatus Dana 52

8. — crassus Giesbr 53

Paracalanidae 54

9. Paracalanus parvus Qaus 54

Pseudocalanidae 57

ID. Pseudocalanus minutus Kr 57

11. Microcalanus pygmseus G. O Sars 66

12. Clausocalanus arcuiformis Dana 68

13. Spinocalaiius abyssalis Giesbr 69

14. — magnus Wolf 72

Aetidiidae 72

15. Aetidius armatus Boeck 75

16. Chiridius armatus Boeck 77

17. — nasutus n. sp 81

18. — modestus n. sp 82

19. — obtusifrons G. O. Sars 83

20. — gracilis Farr 85

21. Aetidiopsis rostrata G. O. Sars 86

22. Udinopsis armatus Vanh 88

Copepoda I.

Calanoida Amphascandria

Page I

I

I

Page

23. Gaidius tenuispinus G. O. Sars 89

24. — brevispinus G. O. Sars 94

25. Gaetanus Kruppi Giesbr 97

26. — minor Farr 103

27. — pileatus Farr 104

28. — miles Giesbr. 107

29. — latifrons G. O. Sars 108

30. — ferox n. sp 1 1 1

31. Euchirella rostrata Claus 113

32. — curti Cauda Giesbr 118

33. — messinensis Claus 122

34. — intermedia n. sp 124

35. — maxima Wolf 127

36. — bitumida n. sp 131

37. Undeuchsete minor Giesbr 132

38. — major Giesbr 136

39. — superba n. sp 137

40. Chirudina Streetsi Giesbr 141

41. — pustulifera G. O. Sars 145

42. — abyssalis n. sp 147

43. — notacantha G. O. Sars 148

44. — parvispina Farran 151

Valdiviella Steuer 154

45. Valdiviella insignis Farran 154

Euchsetidae 157

Euchaete Philippi 157

46. Euchaete norvegica Boeck 158

47.
48,
49.
50.

51
52
53
54
55
56.
57
58.

tonsa Giesbr 166

glaciaUs Hansen 169

Farrani n. sp 172

barbata Brady 1 74

Sarsi F'arran 177

Scotti Farran 179

Hansenii n. sp 181

Bradyi n. sp 182

bisinuata G. O. Sars 183

gracilis G. O. Sars . . .' 185

acuta Giesbr 187

hebes Giesbr 188

41871

Page

Scolecithricidae 189

59. Scaphocalanus magnus Th. Scott 189

60. — brevicornis G. O. Sars 192

61. — obtusifrons G. O. Sars 194

62. — validus Farran 198

63. — globiceps Farran 199

64. — robustrus Th. Scott 202

65. Scolecithricella minor Brady 204

66. — Ingolfii n. sp 207

67. — ovata Farran 208

68. Lophothrix frontalis Giesbr 211

69. Scottocalanus Thorii n sp 215

70. — securifrons Th. Scott 220

Page

Phaennidae 222

71. Coruucalanus chelifer Thomps 222

72. Onchocalanus magnus Wolf 225

73. — cristatus Wolf. 228

74. — hirtipes G. O. Sars 231

75. — affinis n. sp 233

76. Xanthocalanus Greeni Farran 235

77. — pinguis Farran 236

78. — claviger Th. Scott 239

79. — hirtipes Vanh 241

80. Phaenna spinifera Claus 241

List of Literature 245

Explanation of the plates 249

Introduction.

My studies on the Plancton-Copepods, brought home by the Danish Ingolf Expedition, which
were commenced about 1904, have been delayed for several reasons, of which the three principal ones
are: in the first place that I for several years was occupied with other topics, in the second place that the
rich collections of The Thor Expedition from the waters around Iceland as well as those of the Danish
Expedition to East Greenland 1900 have greatly added to the work to be done; the third reason is,
that it was my intention to give so full an account of each species as possible, not only of the adult
males and females but also of the different stages of Copepodites.

On the Material.

The principal source of material was that of the "Ingolf" 1894 and 1895; the investigation of
this expedition "extended over the eastern part of the seas along the west coast of Greenland from a
point a little north of the polar circle to about 58° L. N., two degrees south of Cape Farewell, from
there in a north-easterly direction towards Iceland, the waters round this island and between Iceland
and the Faeroes, lastly eastwards to a line drawn almost due north from the Fseroes to Jan Mayen".
The above quotation is from Hansen's Crustacea Malacostraca I of the Ingolf-Expedition vol. Ill 2
1908, to the introductory remarks of which paper I partly refer. The southern limitation in the
Atlantic was about 60° L. N.

Comparatively few specimens were taken with the trawl; a good many of the samples were
gathered with ordinary vertical nets (P and V) in a depth lying between 50 — 300 fathoms and the sur-
face and a few ones witli a closing net in considerable depth; numerous samples were taken at the
surface with net marked PI, Apst and Cyl during the voyage. The Ingolf collections give a very
good picture of the plankton copepods, the big as well as the small species, but only down to a depth
of 300 fathoms; the deeper layers of these regions are, as shown by the Thor, populated by numerous
species, which were not taken by the Ingolf, at least as far as the Atlantic South and west of Iceland
is concerned. It is a pity that no deep hauls were made- on the West Coast of Greenland; an Atlantic
fauna, identical with that mentioned, should certainly be found here. It is rather interesting that in one
of the few samples, taken with a closing net at a considerable depth near Jan Mayen St. 118 a new
species Euchate Bradyi was found and in another a single specimen of so scarce a species as Scapho-
calanus breviconiis G. O. Sars was secured.

The Ingolfs material from the Atlantic, rich in specimens, of the bigger as well as the smaller
species, which inliabit the intermediate as well as the upper layers, is in a useful way supplemented

The Ingolf-Kxpcdition. III. 4. , . , . j

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b}' the material gathered by the investigation-Steamer »Thor<r, the leader of which was Dr. J.
Schmidt, in the year 1903 — 1905. The region investigated by the Thor is the eastern part of
Denmark Strait, the Atlantic South of Iceland, the Iceland-Faeroe Channel, a few Stations North-
east of Iceland and outside the Ingolf area, the Atlantic, South West of the Faeroes. The hauls of
the Thor were made with the young-fish trawl from the surface down to a depth of nearly a thousand
meters (length of the wire out about 1800 meters.)

As the meshes of the young-fish trawl were rather wide, and as I have only examined few
of the surface samples, the Thor material gives a rather onesided picture of the fauna of pelagic
Copepods from these tracts. Several of the Copepods from the Thor were by Dr. Ove Paulsen sent
to Professor G. O. Sars for determination; to the former of these gentlemen I am indebted because he
kindly lent me these specimens, to the latter, one of the first anthourities on the Copepods, for
much useful information.

The third Danish Expedition to East Greenland under the leadership of the captain in the
navy Amdrup and with the late mag. sc. Soren Jensen as zoologist in the year 1900 has gathered
numerous samples during the journe)'. Surface samples were gathered each hour, day and night, from
19/5 — 25/5 in the western part of the Norwegian Sea from 60° L,. N. 3° L. E. to near Jan Mayen; from
27/5 — 'o/^ during the Journe}' from Jan Mayen to near the East Coast of Greenland (at about 72° L. N.
21° L. W.) in water, which often contained Scattered Ice. During the journey home from i°js to 3%
samples were taken generally each second hour of the day in the ocean North-West of Iceland, in
Denmark Strait and in the Atlantic South of Iceland as far South and East as 59° L. N.
o. 52 L. W.

These surface samples (marked A, B, C, but generally F) as a rule only contain comparatively
few specimens and species, but they give nevertheless a very good impression of the diurnal variations
in the occurrence of the most common species Ca/. fmtnarchicus at least at the surface. The
mentioned Expedition has at Jan Mayen as well as near the Coast of East-Greenland taken some
vertical hauls with the closing net at moderate depth.

In addition to these I have examined a few samples from East Greenland collected by cand.
E. Bay and Dr. H. Deichmann.

Our museum contains a good many samples containing Plancton-Copepods, from the west
Coast of Greenland, collected by Bergendal and W. Lund beck, as well as from the waters around
Iceland, brought home by mag. sc. R. Horring, A. Ditlevsen, W. Lundbeck and Lieutenant in
the navy E. J e n s e n.

To discuss the number of species, which has been found in each of the explored regions by
the different Expeditions as well as other questions concerning the distribution of the species, will
more naturally fall within the next volume of this paper, which will deal with the Calanoida
heierarthrandria\ in the next volume I hope to be able to publish a list, showing the number of
species and the proportionate number of the specimens of each successive stage occurring at
each Station.

At present I am only going to say a few words about the number of species brought
home by each Expedition. I have altogether examined 79 species, which probably belong to the region ;

COPEPODA

among these 13 were new to science. The Ingolf has only collected 21 species of which 3 were new,
the Thor has collected 69 different species (8 however outside the area explored by the Ingolf), of which
II were new, and the Danish East Greenland Expedition 1900 has only taken 13 different species, of
which only one has not been recorded previously. Of the Calanidae and related families the Ingolf
has taken 7 species, the Thor 9 and the 0.Exp. 1900 5, of the Aetidiidae the three expeditions have
taken 6, 29 and 3 species respectively, of the Euclt(etidae the Ingolf has taken 4, the Thor 12 and the
0.Exp. 3 species and of the Scolecithricidae the three expeditions have taken 4, 19 and 2 species
respectively. Of species, which by previous authors were recorded from the examined region, only a
single one Udinopsis armata Vanh. was not taken by any of the expeditions.')

On the Literature.

Without underestimating the fine papers by E. Canu and Th. Scott, it must be admitted,
that Giesbrecht and G. O. Sars are the two modern zoologists, who have contributed most to the
knowledge of the Planctou-Copepods. The work of the former indicates a new epoch in the studies
of these animals; unfortunately the arrangement of the topics in his main paper is so unpractical,
that it is often very difficult a to derive full advantage from the vast amount of information, which is
found in it. Giesbrecht has sometimes been blamed for giving unneccessarily many details for
the definition and understanding of the species. I do not share this opinion, as it sometimes occurred
to me, that details necessary for the limitation of two nearly related species were wanting in his
description. G. O. Sars has in many ways contributed greatly to the study of the Copepods as well
as to that of the other Crustacea; his descriptions are lucid and supported by numerous practically
arranged figures, but might sometimes be a little more exhaustive.

In the last ten years numerous Plancton-Copepods have been described from the deeper layers
of the North-East Atlantic as well as from other ocean tracts; the three principal authors, who have
described these species are Farran, Wolfenden and A. Scott. The papers of the first of these
naturalists have a direct bearing upon the Ingolf-Investigations ; he has given good descriptions of
numerous new species and most useful information about tlie Copepod-fauna of the Atlantic Slope
of Ireland. Wolfe n den's papers often include a number of useful characters and details, supported
by beautiful drawings, but he does not alwa)'s seem to have accepted the classic rules of nomenclature.
A. Scott's main-paper on the Copepods of the Siboga Expedition, which only partly falls within
my sphere, contains most useful lists of synonymy, descriptions of numerous new species and several
new characters; his descriptions are according to my opinion often a little too meagre for the definition
of nearly related species.

When speaking of the studies on the Plankton-Copepods of later years, I think a few words

may be added about a most useful paper by Koefoed & Dam as on the collections brought home

by the due d'Orleans. It may perhaps be allowed to set forth a few words of criticism. It is a

pity that the authors have not wished under each species to give a full acouut of the biological facts,

I) Wolfenden (1904 p. 112) has from the cold area of the Faeroe Channel mentioned four species viz: Bradyidius
armatus Gbt., Udinopsis bradyi G. O. Sars, Bryaxis brevicornis Farr., Ctenocalamis vantts Gbt. and Scolecthrix similis Gbt., but as
they are all found south of the 60° L- N. I have not included them in this paper. The same is the case with Oothrix
bid^ntata Farr. which according to the due d'Orleans was secured at 75° L. N. 14° L. W., somewhat north of the area, inclu-
ded in this paper.

I*

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relating to depth, salinity and temperature, and that they have missed the opportunity of giving a new
description of several species, imperfectly known. In the following I have tried to collect the
facts, found under each Station in their paper, under each species, and it will be evident that I sometimes
differ from the two authors in their conclusions from these very facts. It seems to nie, that these
small defects, give prominence to the surprising amount of useful information, which makes this
expedition one that may in several ways be regarded as an example.

With the useful papers of Dam as, Paulsen, Esterly, Kraeeft and Oberg I am going to
deal later on.

On systematic Characters.

In addition to the systematic characters, used by most authors, I think that good characters
may be found in several organs, the importance of which has been overlooked or underestimated:
viz., the rudimentary appendages of the male, the structure of the genital apparatus in the female, the
system of glands in the natatory legs and the more detailed structure of the labrum and labium.

In addition to the good characters, which are generally found in the fifth pair of legs in the
males, good characters are f. inst in species of Eiichirella found in the rudimentary mouth appendages
as well as in the first pair of leg.s, which differs distinctly from tliat of the female.

It is generally recognised, that the structure of the vulva is most important from a systematic
point of view, but as it is often rather complicated, the figures of it are often rather imperfect. In
the description of the nearly related species of Eiichcele I have given a somewhat more detailed
description, well aware, that a complete dissection is quite necessary for understanding the morpholo-
gical as well as the systematic importance of all these lists and bars; a study of this nature would
certainly have enhanced the value of this paper but would have delayed its publication too much.

Cutaneous glands and pores, through which their contents are discharged, have been described
and mentioned by different authors, who, however, like Giesbrecht took most interest in these
organs in species in which they were probably luminous.

The glands which are found in the natatory legs do not seem to have interested the authors
very much; Giesbrecht has in his great paper figured glands, filled with globules of oil (?), in
the legs of Euchirella rostrafa (pi. 15 fig. 27) but as far as I know or remember, they have not
been mentioned by others. As these glands are often ver\- prominent organs and generally are connected
with the ducts, which are often filled with drops of oil, I think they are of great importance for the animals;
they are generally not unicellular as several elongated nuclei are often seen at the base of an elon-
gated sac; a study of the anatomy and histology of these glands should be very interesting on fresh
material, but did not fall within the scope of this paper. As the glandular ducts open in a rather
uniform way in the natatory legs, and as the exact number and position of these glandular pores
which are alway placed on the anterior surface sometimes have a systematic importance of no small value,
I have carefully examined them in the different species, to the description of which I refer for details.
The original number of pores seems to be the following: one near the base of the external spine
(Se) of the third basipodite, one corresponding to the Se of the two first outer segments and three,
corresponding to the 3 Se of the third outer segment (cf. pi. I fig. 36); this number is reduced in

COPEPODA

most species. The pove in the third basipodite is generally wanting, and so are the two proximal
pores in the third segment of the exopodite (of. pi. II fig. 5 a); in several species the pore of the
Re I is wanting in the second pair of legs, bnt very seldom in the third and fourth pair; this kind
of pores was never found in the first pair of legs and is wanting in the fifth pair in species, in which
this pair is of no use for natatory purposes. In the Scolfcithricidae the pores are generally poorly
developed. To illustrate the differences which may be found in species, which really are very nearly
related I refer to the differences in Chiridius aniiattis^ nasittiis and modestus (cf. pi II fig. 3 a, 4 a
and 5 a); the greatest development of the glands and pores is found in Euchirella^ in E. rostrnta and
iiicssi)iciisis the usual pore at the base of Se Re I pes. Ill was present, but in E. curficauda it was
wanting. The number of pores in the adult and the young ones of the penultimate stages are gene-
rally alike, but in EucJiirclla rostrata the pore, which is found at the base of Se i Re III pe.s. II — IV,
is wanting; the younger stages have the number of pores more or less reduced as realised in the
decription of the different stages of, f. inst, Calamts fir^narchicus.

In addition to the mentioned system of pores, a small pore sorrounded by delicate hairs is
found on the anterior surface of the third segment of the endopodite in the second to the fourth pair
of legs (cf. pi. I fig 3e; pi. VIII fig. 18 c).

Pores arranged in a characteristic way (pi. I fig. 3 f — g) are found in Megacalanus and Alacro-
calanus^ to the description of which I refer.

In the first pair of legs pores are often found in the outer margin of the exopodite (cf. pi. VI fig. 2 a).

The mouth of the Copepods shows within the different groups a very different structure, well
adapted for the habits of the animals; as far as the parasitic or semiparasitic forms are concerned
fairly good descriptions are found in literature.

The Plancton-Copepods probably nourish on extremely small plants as well as on bigger ones,
which are extremely well masticated, in a way that the shells or fragments of Diatomes, f. inst, are
very seldom found so well preserved, that their exact nature could be determined (cf. Dakin).

The first and I think the most exhaustive account of these organs in one of the Calanoida
has been given by Moebius for Eiicha'te norvegica^ his carinata (1875 p. 271; tab. VII); Clans has (1863
p. 25) given a short, but not very good description of the structure in PUiiroiiiiua, but the following
quotation indicates, that he has examined the structure in other forms as well.

»Auf die zahlreichen Modificationen, welche in den einzelnen Gattungen eintreten, im speciellen
einzugehen wiirde zu weit fiihren und nicht das geniigende Interesse bieten, zumal diese Bildungen
wegen der Schwierigkeit ihrer Untersuchung nicht leicht systematisch zu verwerthen sind.«

In all the Calanoida aiiiphascandria^ examined by me, as well as in several of the heterarthrandria^
f. inst Plcitroinvia^ Metridia, Temora, Batltypontia, and with a few not very important modifications
from a morphological point of view in Liicicuta^ Anomalocera and Acartia, the mouth-organs show
the following structure. The opening of the intestinal duct is placed between a prominent labrum
and less prominent labium, on each side bearing a labial lobe, corresponding to the paragnatha of Clans;
the labrum and the labium are on each side connected with a chitinous framework, which forms a
bridge over the manducatory part of the mandibulae, and in a way forms the lateral limitation of the mouth.

COPEPODA

In front of the labrum a sometimes hairy protuberance is found ; this was by Sars in Euchcete
designated the cpisiovia\ I have in this paper followed him, where the organ belonged to the somite
of the antennae. The labrum proper, which is placed in the mandibular somite is often subdivided
and has in the Euchcptidac and Scolecithricidae its free or anterior surface more or less hairy, in a
way that often is of systematic importance (cf. pi. VI fig. 2 b, 7 a, 14 a and pi. VII fig. 5 e, 9 b and
7 c); along the hinder margin of the labrum, separating the anterior and the oral surface, marginal
bristles are always observed (pi. II fig. 3 b; pi. IV fig. 5 e). The oral surface is adorned with a more
or less developed chitinous framework, to which longitudinal muscles are fastened; this sjstem is by
comparison with fig. 7 f. pi. II and fig. 2 a and 5 e pi. IV seen to be differently developed in the different
forms. Along the median line three central circular spots, in the middle with two parallel lines, as well
as a fourth more posterior one, with a lateral one on each side are found; laterally a few spots, which
may perhaps be regarded as muscular spots, are observed (cf. pi. IV fig. 5 e). About the nature of
these four central circular striated spots I do not know anything; they are certainly not muscular
spots, perhaps sensory ones. Around or behind the fourth spot a bigger or smaller transverse row
or area of spines or bristles is observed; the systematic importance may be realised by comparing
fig. 2 a and 5 e pi. IV. The oral surface of the labrum is on each side near the middle adorned with
a lateral longitudinal series of bristles or spines, which is again dissolved into five groups, the more
detailed variations of which show interesting differences between species and genera, as seen in
numerous figures (pi. I — VII).

The labium is gradually fused with the posterior wall of the pharynx; it is generally adorned
with curious structures. In the middle a compactness in the chitinous skeleton the lamina labialisi is
found; in front it is not well separated from the wall of the pharynx, but its hinder margin seems to
be partly free, and shows many variations, as seen by comparing the figures (pi. II fig. 7 f , 2 a and
3c; pi. Ill fig. 5e; pi. V fig. 26; pi. VI fig. 3b, 11 b and 13 b); in the Scolecithricidae this organ seems
to be wanting or poorly developed (pi. VII fig. 4 e and 7 d).

Laterally to the lamina labialis on each side a longitudinal row of 6 generally well articulated
spines is found. I have designated it the scrrula sexdentata, and as it was found in all the examined
genera except Candacia and Heterorhabdus within the Calanoida, but not in any of the few genera
of other groups, which were examined, it is certainly of some systematic importance. In front of the
lamina labialis and the serrula, curved longitudinal rows of bristles or granules are found, which as _
seen in the figures show specific as well as generic differences (pi. I fig. i c; pi. II fig. 2 a; pi. Ill
fig. 5e; pi. IV fig. i c, 2 c and 3d; pi. V fig. 2 b and 4 c; pi. VI fig. i b, 2 d, 3 b, 5 a and 10 b and
pi. VII fig. 2 c, 4 e and 12 c). Behind the latnina labialis, more or less well developed areas, covered
with granules or spines are found (pi. II fig. 7 f.). The labial lobes as well as the area between and
behind are covered with series of delicate hairs; the arrangement of these series is different in the
various genera, but these differences are probably modifications only of a general system (cf. pi. II
fig. 7 f ; pi. IV fig. id, 4 c and 5g; pi. V fig. ic and 5 f ; pi. VI fig. 5 b). Behind the area labialis in
the maxillular and maxillar somites an intricated system of hairy areas is sometimes found, f. inst. in
Calanus hyperboreus (pi. I fig. i d).

In the literature I have found a good descpription of these organs in Laophonte and Hersiliodes

COPEPODA

(Canu 1892), but their structure is quite different from the one described; lately I have examined the
labrum and labium in two genera of the Harpactoida^ in Oncaea and in Oithotia, but only in the
latter genus found a structure not quite dissimilar to the one described.

In the nauplius of Calafius I have not yet succeeded in elucidating the structure of these or-
gans; in the first postlarval stage of C. fintnarchictis the structure is in its main feature like that of
the adult one.

The structure of the mouth organs in the males is, in species in which the oral appendages
are not reduced, scarcely different from that of the female, but in other forms, it is more or less
reduced (cf. pi. IV fig. i e; pi. VI fig. 3 e).

From the above it seems to me to be evident that the study of these organs in different forms
is of no mean importance.

On postlarval development.

Most modern authors, who have studied the Plancton-Copepods from the systematic point of view
have only paid attention to the adult males and females, even when younger specimens were present; in
later years Ob erg has given a description of the larval stages in several species and Kraeeft has paid
much attention to the postlarval development in a very interesting paper; Dam as, Paulsen and
Stephensen have for single species contributed to our knowledge of the development. It is generally
understood that G fob ben is the first who has described the nauplius in Calanus finmarchicus and
that Gran was the first to give an account of the postnauplial development; both statements are wrong,
as Kroyer, as early as the year 1847, followed the development of Calanus finmarchicus from the
nauplius to the adult (or more correctly the penultimate stage). In this paper I have not dealt with
the larval forms, but I have tried and generally succeeded in determining the postlarval stages;
I have named the first postlarval form stage I, and the adult male and female stage VI. About the
differences between the different stages in each species, and the reductions in the limbs I refer to the
systematic part; the most complete account is found in the description of Cal. finmarchicus. The
mouth-organs are generally not reduced in the Stages IV — V; the number of setae in the exopodite
of the maxillulae forms an exception to this rule. In the adult female the number is 11, in stage
V it is 10, in stage IV it is 9, in stage III it is 8, in stage II it is 7 and in stage I probably 6.
The main differences between the stages is found in the number of natatory legs and number of
somites of the urosome.

Nonnenclature.

In the naming of the different appendages I have followed Hansen as well as Giesbrecht,
who somewhat later arrived at the same result. Hansen has shown that the antennae., mandihilae
and maxillipeds really have threesegmented basipodites. The structure of the maxillulae in Valdiviella
insignis shows clearly, that the basipodite of these limbs are threesegmented; the first basal segment
is adorned with the Li I; the second bears the Le and a single Ivi (II c^^ III); the third basal segment
which is distinctly articulated to the preceding one, supports the tvo rami. The natatory legs ap-

8

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parently have only two basal segments; but according to Hansen the first basal segment of the
natatory legs is probably fused with the complicated chitinous system of the ventral surface; if this
is right, the first basal segment of the authors is really the second, and the second the third. In the
description I have followed this nomenclature; the last basal segment is accordingly designated the
third one (corresponding to the second one of most authors in the antennae, mandibulae, maxillulae,
maxillipeds and natatory legs); the second basal segment in my description corresponds to the first
one of most authors in the maxillipeds and natatory legs; the second basal segment of the mandibu-
lae and the first one of the antennae are as show by Hansen poorly developed.

About the different abbreviations used in this paper I refer to the following list.

Plaucton nets used by the Ingolf.

V signifies the big vertical plancton net.

V — the smaller one.

V^ — net with different width of the meshes.

P' — Apstein's vertical net (Nr. 20).

Apst. = A. The same net used in the surface.

PI. — Surface plancton net.

Cyl. — Cylindric net.

Closing net is the net of von Petersen-Ch un,

modified by H e n s e n.
Yt is the abbreviation of the youngfish trawl

used by the Thor-
0. Exp. 1900 is the abbreviation of The Danish

Expedition to East Greenland in the year 1900.
A. B. C. D. E. and F. are the different kinds of

surface nets used b\' this expedition,
f^ = adult female,
fc? = fullgrown male.

V = a young specimen.
St. = the stage.

St. I — VI signifies the postlarval development;

St. I is the youngest first postlarval stage and

St. VI is the adult male or female.
The abbreviations used in the description of the

species are those used by Giesbrecht and

following authors.
Basp. I — III = The first, second and third base-

podite.
Ri ^ Ramus internus.
Re = Ramus externus.
Ri I — III and Re I— III signifies the number of

the segment of the endopodite or exopodite.
cvi signifies that two segments are fused e. g.

Re II ^ III and segment 8 "^ 9 of the anten-

uulae.
Si = an interior seta.
Se = an exterior seta.
Sp ^ a posterior seta.
Sa = an anterior seta.
Spr = a proximal seta (antennulae).
Sd = a distal seta (antennulae).
St ^ a terminal seta (Re III pes I— V).
L or Lob = lobe.

Le or Li = Lobus externus or internus.
Sp ^ Spermatophores. Sp. within a bracket indi-
cates that specimens, bearing these structures,

were secured.
Sin. and de.Kt. means sinister and de.xter.

On the description of species.

As I have personally examined all the samples from the three expeditions myself and have picked
out a fairly big number of specimens, generally more than a hundred, if so many were present, adult
as well as young ones, I think that we get a fairly good impression of the proportion between the
different stages; Paulsen has as far as Calauns finmarcliiczis is concerned picked out a hundred
specimens to get an impression of the proportional distribution of the stages. In the systematic part
I have given an almost complete description of the species, which were only imperfectly described;
in cases, in which good descriptions have been given by previous authors, I have only added features,
overlooked, or differing from existing description. Not only the males and females of the last stages

COPEPODA

have been described, but also the younger stages, as far as they showed features of any interest The
descriptions are as a rule rather long, partly on account of the new characters, which are taken into
account, partly because it often struck me, that existing descriptions were often too wanting in details
for a sure definition of nearly related species.

Under each species is found a list of synonymy, which I have tried to make as complete as
possibly for the }ears after the publication of Giesbrecht's classical paper; for each species I have
given the measurements of each examined stage.

After the description is added a few words of the variations and parasites, if any have
been observed. Under occurrence I have only given my personal observations, but under distribution
I have dealt with the facts, previously published, relating to the occurrence of each species withiu
as well as outside the explored area. Under remarks the whole systematic position of the species
is discussed.

On variation and parasites.

In a good many species viz: Rhincalanus iiasufus, Eucalanus elongatus, Paracalanus parvus^
Pseudocalaniis minutus, Chiridius armatiis, Gaetanus Kruppi., G. pileatus and G. latifrous, E^tchirella
rostrata and curticauda^ Euchate tonsa and barbata and Scaphocalanus magnus variations of different
kinds were observed; most common is variation in a rudementary fifth pair of legs and in the struc-
ture of the setae of the furcal branches; several of the variations are probably due to traiunata and
regeneration, others certainly represent a kind of atavism. To study the whole question of variation
within the Copepods or to collect all the published facts (cf. Wolfenden and Steuer) does not lie
within the frame of this paper. But as such facts are rather scarce, and as they may be important
for a future student of these topics, it seems to me to be the duty of each observer to make his per-
sonal observations known, even if they are fragmentary. Negative statements are seldom of much
value; but nevertheless I think it rather curious, that abnormal segmentation, which is fairly common
in the Arachnids, Insects and Annelids, was never met with in any of the examined, I think several
thousand, Copepods; to my knowledge no case of abnormal segmentation has been observed in auy
of the Crustacea.

In several species parasites of different kinds have been observed ; I refer to the description
of Rhincalanzis iiasiitus, Ghiridiiis aniiahis^ Gaidius tcnuispinus and brevispiiiiis, Gactauus Kruppi,
pileatus and latifroiis, Uiidcuchccte snpcrba and Cliintdiua noiacaiifha.

The Ingolf-Expedition. Ill 4.

Fam. 1. Calanidae.

I. Calanus finmarchicus Giinnerus. (Textfigs 1—5).

1765. Monoculus finmarchicus n. sp. Guimerus, pp. 175, \ 1903,

fig. 20—23. 1903
1842 — 1845. Calanus spitsbergensis n. sp. Kroyer, pi. 41, figs.

I a— u. I 1903
Calanus affinus n. sp. Kroyer, pi. 41, fig. 5.

Calanus quiuqueannulatus n. sp. Kroyer, pi. 41, fig. 3. 1904
1S49. Calanus spitsbergensis Kr. Kroyer, pp. 531—542,

P- 552- 1905

Calanus affinis Kr. Kroyer, pp. 544—545, p. 553. 1905

Calanus quinqueannulatus Kr. Kroyer, pp. 545 — 1905

546, p. 553- 1905'

1863. Cetochilus helgolandicus n. sp. Glaus, p. 171, pi. 1905

XXVI, figs. 2—9. 1905
18S6. Calanus finmarchicus Guun. H. J. Hansen, pp.

255—256. I 1906.

1892. Calanus finmarchicus Gunn. Canu, p. 170, pi. I; j

figs. 13—19. I 1906.

1892. Calanus finmarchicus Gunn. Giesbrecht, p. 89, taf. 1 1906.

6 — 8. 1906.

1897. — — — Vauhoffen, p. 278, pi. i

fig. 7. 1907,

1898. — — — AuriviUius, pp. 67 — 69.

1S98. — — — Giesbrecht - Schnieil, 190S

pp. 14—15-

1899. ? — — — Brady, p. 32. 1908

1899. — — — T. Scott, p. 90.

1900. — _ _ Wheeler, pp. 164— 1908

165, fig. I. 1910.

1900- — — — G. O. Sars, p. 2. 19 10.

1901- — - — T. Scott, p. 338. 191 1
i9<^'2- — — — Gran, pp. 56 — 65. 1911
1902. — — — Mrazek, pp.503— 519, 1912

figs. 1—4. 1913
I9°3- — — — Jensen, Johansen&Le-

vinsen, p. 303, tab. I. I9I3.

1903- — — — G. O. Sars, pp. 9— 11, |

pi. I— III, I

Calanus finmarchicus Guun. I. C. Thompson, p. 15.
Calanus helgolandicus Claus. G. O. Sars, pp. 11— 12,

pi. IV.

— — — Thompson & Scott,

p. 241.
Calanus finmarchicus Gunn. Wolfenden, pp. 126 —

127.

— — — G. O. Sars, p. i.

— helgolandicus Claus. G. O. Sars, p. i.

— — — Th. Scott, pp. 221.
Calanus finmarchicus Gunn. Farran, p. 30.

— — — Damas, pp. i — 23.

— — — Esterly, pp. 125 — 126;

fig. I.
Calanus septentrionahs Goodsir. Norman & Scott,

p. 126.

— helgolandicus Claus. Pearson, pp. 4 — 5.

— finmarchicus Gunn. Paulsen, pp. 1 — 21.

— — — Williams, pp. 639 —

640.

— — — Damas & Koefoed, pp.

382-93; 405-

— — — V. Bremen, pp. 7--8;

fig. I.

— helgolandicus Claus. v. Bremen, pp. 8 — 9 ;

fig. 2.

— finmarchicus Gunn. Farran, p. 20.

— — — Steuer, p. 21.

— — — Sharpe, pp. 409—410.

— — — Farran, pp. 83-89.

— — — Esterly, pp. 140— 151.

— — — Esterly, pp. 282 — 295.

— — — Stephensen, pp. 308

—310.

— — — Stephensen, p. 71.

COPEPODA II

Giesbrecht refers this species to Monoculus fmmarchtcus Gunnerus, (p. 32 — 33). Kiroyer
(1848 p. 528) has already shown that Gunnerus species was a Calanus, but he thinks that the
decsription is too incomplete for a sure indentification. In contrast to Giesbrecht I think that it
is quite impossible to tell if the species belongs to Cal. finmarchicus or to young specimens of Calanus
hyperboreus. The one figure in natural size shows a small animal (c. 2 mm. long) even less robust
than most specimens of C. finmarchicus \ this figure and the author's remarks about » quite small
animals« certainly speaks against its identification with Cal. hyperboreus, but the remark about, the
very pellucid, shining colour without indication of the reddish tint which is most often found in Cal-
finmarchicus, especially the antennulae, does not bear out the same opinion. The biological conditions
under which the two species are found in the polar region, are almost identical, and do not allow
any conclusion. But as the name Cal. finmarchicus has been once recognized, and as it cannot with
better, probably with smaller, right be applied to Cal. hyperboreus^ I think it right to follow Giesbrecht.
In other respects as far as the synonymy is concerned I refer to Giesbrecht; as I have however

As I have had the opportunity of examining Kroyers original specimens of Cal. carinattis and cristatus, I think that
a few words of their systematic position would not be superfluous, even if these species belong to another geographical region.

Calanus carinatus Kroyer.

1849. Calanus carinatus n. sp. Kroyer, p. 554.

1S56. — brevicomis u. sp. Lubbock p. 11.

i860. — — Lbk. I,ubbock, p. 117.

1892. — — Lbk. Giesbrecht, p. 90; taf. 6, 7, 8.

Of this species Kroyer has examined a single not ver}- well preserved adult female from the coast of Brazil. In
spite of the differences enumerated below I think it is identical with the midatlantic species, which Giesbrecht has refeiTed
to C. brevicomis Lubk. The total lenght was 2'o + 06 = 26 mm. The marginal frontal keel is more prominent than figured
by Giesbrecht (t. 6, fig. 7) and the rostral spines are more stiff, but the lateral outline of the labrum shows the same
characteristic structure as figured by Giesbrecht. The fourth abdominal somite is dorsaUy i'2 as long as the fifth one as
shown in Giesbrecht's fig. 18, but in contrast to his text, in which he writes that the fifth somite is a little longer than
the fourth.

The antennulae extend a little beyond the tip of the fourth abdominal somite; the segment VIII — IX are less
well separated than the rest. The distal setae of segm. VIII and XII are not spinelike. The measurements are at least
different from Giesbrecht's figure of the male (taf. 8 fig. 5); the segment 24 is a little shorter than the 23, which is
scarcely as long as the 22. The 25 segment is rather mutilated, but seems scarcely to be half as long as the preceding one.

No marginal setae were found along the inner margin of the second basipodite of the pes II, IV and V, and no teeth.
The first Se of the Re III divides the outer margin in equal parts in the second pair of legs but in the fourth pair the
portion, proximal to Se i is 17 (not 1-4 as in brevicomis) as long as that distal to it.

Calanus cristatus Kroyer.
1845. Calanus cristatus n. sp. Kroyer, pi. 41, figs. 6 a— k.
1849. — cristatus Kr. Kroyer, pp. 546-55©, p. 553-
1884. - — Kr. Poppe, pp. 282—286; taf. XX, fig. 1-6.

1892. — — Kr. Giesbrecht, p. 91, t. 6, figs. 14 — 15.

Of this species I have examined 14 young specimens (Kroyers original ones), of which 12 belonged to pernultimate
stage and a single to stage IV. They were all rather mutilated, but nevertheless it is scarcely doubtful that Poppe's and
Giesbrecht's rather imperfect descriptions refer to this species. Total length is 8-6 (7'0 -)- i-6|. Shape of the head is alike
Giesbrecht (fig. 14—15); the lateral corners are rounded and not produced. The antennulae extend with the 25 segment
beyond the end of the abdomen. The segment 8 cvi 9 are only indistinctly separated and together just as long as the segment
21, which is 115 as long as the segment 22. The latter is n as long as the 23 and 25 segment, which is 1.3 as long as
the 24. The mouth-appandages scarcely provide features of interest. The Ri of pes I— IV possess no Si The Re III pes II
is by the Se I divided into a proximal shorter and a distal almost r2 as long; the exopodites of the three last pair of legs
are wanting. The inner margin of the first basipodite of the fifth pair of legs is smooth.

12 COPEPODA

had the opportunity of examining Kr oyer's original specimens of this species, I do not find it out
of place to add a few remarks.

Kroyer's description and figure of Cal. Spits bergensts apply withoiit doubt to the mature
females; his description is clear and remarkably exhaustive; he has seen and described the receptacula
seminis ; his original specimen is a Cal. finviarchicus. Kroyer's description and figure of Cal.
af/inis applies to young specimens (St. V), but of his 3 original specimens the two belong to the
fourth stage. The description and figure of Cal. qutnqiicantmlalus refer without doubt to the male
of Cal. finmarchiais ; Kroyer's original specimens were not preserved, but a number of specimens,
determined by Kroyer as C. qjiinqueanmclatus, were males of Cal. finmarchicus.

As Kroyer had unfortunately not examined mature specimens of Cal. hyperborcus. but only
young animals, he was obliged to establish his species on specimens of stage V; accordingly he did
not realise that the number of abdominal somites is not a systematic character, and was not able to
understand the full cyclus of development from nauplius to fullgrown animal of Calainis /ini/iarc/iiciis
oj hyperborcus. He realised that is was too difficult for him to distinguish the earlier stages of these
two nearly related species. Starting from the stage V of Cal. hyperborcus he regarded the stage IV
as the oldest larve; he has given fairly good figures and clear descriptions of stage I — IV; he has
recognised the nauplius and metanauplius as forming part of this cyclus. I think that Kroyer was
the first to set forth the almost complete development of one of the Calanoid; so full a description of
several features does not seem to have been published for this species in spite of its importance (cf.
Dam as p. 8, who thinks that Gran is the first to recognise the larval stages).

As I have been obliged to examine a big number of specimens of this species from the wide
area investigated by the Ingolf, the Thor and the East-Greenland Expedition, I have felt it necessar}'
to try to solve the question whether Sars is right or wrong in establishing the two species Calamis
finmarchicus and C. helgolandictis^). According to Sars:

The female of the more southern form C. helgolattdicus is about 3 mm. long, the male 2'8 mm.,
while C. finmarchicus is 4 and 3-6 mm. respectively; the former species is more narrow in form with
more angularly produced head. The urosome is in Cal. finmarchicus about half the length of the
metasome, and the caudal rami are somewhat longer than the anal somite, while Cal. helgolandicus
has the urosome exceeding half the length of the metasome and the caudal rami scarcely longer than
the anal segment In Cal. helgolandicus the antennulae extend only 2 segments beyond the caudal
rami but 3 in Cal. finmarchicus. The most important difference is found in the fifth pair of legs of
the male, which are more asymmetrical in Cal helgolatidicus with the Ri sin. extending a little beyond
the Re i (not beyond the middle of Re II) and with the Re III scarcely exceeding half the length of
the Re II (not nearly so long).

The difference in size does not, as suggested by Sars, always correspond to a more northern or
southern distribution as pointed out by several authors. Mrazek (p. 502) has in the same samples from
Spitzbergen found mature females varying in size from 3-4 to 5-2 mm., Dam as and Koefoed have
from the same locality seen specimens varying from 3-2 to 5-4 mm. (cf. p. 382). Giesbrecht's spec-

■) .A, name, which Normau & Scott with good reason propose to replace with Cal. septentrionalis Goodsir.

COPEPODA 13

imens varied from 27 to 4-5 mm. I have found the same to be the case in several samples from the
west coast of Greenland.

In a sample from Jakobshavn I found 100 specimens (f?) varying in size from 3-3, 3-5, 3-8 to
4-1 and 4 specimens 4-6 to 53 mm. long; a young female from the same sample measured 3-9 mm.,
19 young ones measured about 3 mm. From Ingolf St. 28 f? of size from 3-5 to 5-1 and j'oung spec-
imens from 3-5 to 4-8 were taken.

By comparing the length of the urosome and anterior portion in specimens from different
localities and of different size etc. it was quite impossible for me to find any character of value. In
specimens of f? from the west coast of Jutland (Thyboron, Thor '7/3 04) the head was certainly more
produced than in specimens taken 73° L. N. 8° L,. E. by Johannes Petersen, but in the former
the caudal rami were scarcely as long as wide, and a little longer than the anal somite, and in the
latter distinctly 2-i as long as wide. In 3 of the mentioned specimens from Denmark the antennulae
reached three segments beyond the tip of the urosome, but in 2 other specimens two only ; in specimens
from Spitzbergen (c. 3-4 mm) they extended three segments beyond the end of the urosome, but in a
big specimen from Greenland (53 mm) with the head even less produced than the specimens from
Spitzbergen the antennulae extended only two segments beyond the urosome.

As far as the shape of the head is concerned the differences between the different types are
better marked in the males than in the females; as far as the characters found in the fifth pair of
legs are concerned I first tried like Mrazek to find a character in the variations of the spinulation
of the inner margin of the second basipodite, but like him without success.

In Sars' figures of C. /hitnarchims the pes V does not extend to the end of the abdomen;
in none of my specimens the pes V is so short as figured by Sars; in all my specimens they extend
to or almost to the end of the abdomen. In all the examined males (from Denmark, Greenland or Spitz-
bergen) except in a single one from Denmark, the Ri III sin. reached beyond the middle or almost
to the end of Re II. In a single specimen from Denmark the Re II sin. was 17 as long as the
Re III, but in most other specimens the Re II was 1-4 or 1-5 as long as Re III; the last segment
differs from Sars' figures by a more or less marked rounded protuberance basally and inwards.

Scott (1905), followed by Pearson (p. 5), has accepted Sars' two species, but most authors
agree in regarding the proposed characters as insufficient f. inst. Wolfenden (1904 pp. 126—127),
Farran (1905 p. 30) and Gough (1905). Mrazek has (1902 pp. 502 — 506) without knowledge of
Sars' point of view tried to solve the question. Without result he tried to find characters in the
dentation of the inner margin of the first basipodite of the fifth pair of legs. He writes p. 504:
»Etwas konstanter erwiesen sich die Langenverhaltnisse der vorderen Antenne. Die Lange derselben
ist der L,ange des Korpers umgekehrt proportionell. ; He also found differences of some value in the
armature of the legs, and the relation between the length of the different parts of the body; but he
rightly thought, that a detailed study of a lafger material, consisting of specimens, originating from
a different region of the ocean with statistical methods of studying the limit of variation, would scarcely
solve the question, without at the same time studying material from well defined geographic regions.
The question ought soon to be properly investigated, for if Cal./ininarchicus and helgolandiciis should
really be proved to belong to two different species, a good deal of the vast amount of knowledge

14

COPEPODA

about the biology and distribution, collected in the last years, is in danger of losing considerably in
value. All questions regarding development, propagation and distribution should in most regions be
extremely difficult to investigate, if we instead of a single well defined species had two very
badly limited.

Description J" — $. Size: f$. 2'8 — 5-5 mm. fj*. 3 — 4-4 mm. (Smallest specimens Fseroe Iceland
Channel; largest Davis Strait).

The number of secretory pores scarcely differed in the males and females, or in specimens
from different localities. In the first pair of legs no secretory pores were found; on the anterior sur-
face of Ri I, at the base of Se, sometimes a minute pore (?) was seen. In pes II— V a minute pore
was found on the anterior surface at the base of a minute Se of third basipodite; in the Re I— II a
more or less distinct pore was found at the base of Se in the four last pair of legs, and a distinct one
was found at the base of the Se 2 — 3 Re III, but in addition to these in the pes III — IV a pore was
found corresponding to the missing Se i Re III, in pes II this pore was most often wanting. The
shape of the labrum etc. (cf. textfig. 6) is somewhat different from Sars' fig. (pi. I). Between the
insertion of the antennulae a small elevation is found, which by a transverse groove, less prominent
than shown in the figure, is divided into a shorter anterior portion (a) and a longer posterior one (b).
Separated from this by a narrow groove and between the insertion of the antennae a low elevation
(c), slightly convex from before backwards and from side to side is seen. In front limited by a trans-
verse groove, behind by the free posterior margin and laterally gradually continued into the transverse
chitinous bar, situated between the articular cavity of the antennae and mandibulae respectively, the
labrum proper is found. The mentioned chitinous bar is medially to the articular cavity of the
mandibulae connected with the area labialis, thus forming the chitinous bed, in which the manduca-
tory portion is situated (cf. Sars' fig. pi. II). The labrum proper has in front, in the middle, a prominent
tumulus, beset with a number of long bristles directed backwards. On each side of the process an
oblique series, directed outwards and backwards, sometimes fused with the lateral marginal row, is found;
it consists of short spinelike hairs. In front of hinder margin on each side a group of fairly long setae,
beginning in the middle and directed backwards and outwards, is observed and laterally a marginal
row of rather short spinelike hairs is found.

The oral surface of the labrum shows an arrangement alike that of Cal. hyperborcus (pi. I fig.
I b), but the enlarged group in front is less developed (differing on the two sides in the two examined
specimens), the first group is converging anteriorly, the second group is medioconvex, well separated
from the first group, but only indistinctly from the third one ; the third to the fourth groups are partly
fused and consist of several rows of hairs. Transversely between the last series only a few teeth
are found.

The lamina labialis (textfig. i), which seems to form a part of a transverse chitinous system,
has posteriorly a median tooth, and on each side two or three teeth (often assymmetrical). In front
of the lamina labialis a delicate granulation is found in the middle between a median series of shorter
and a lateral of longer hairs. Behind the lamina and between the serrulae 6dentatae an outer group
of fairly delicate hairs and a median one of thick granules, fused with a group between the labial lobes

COPEPODA

15

are found. The arrangement of hairs on the labial lobes and the somites behind seems, as far as made
out, to be like that of Cal. hyperboreus. In several specimens it was seen that the transverse line, which
limits the maxillar somite posteriorly, is continued just in front of the articular cavity of the maxilli-
pes and laterally into the membrane, dorsally and posteriorly limiting the head. Accordingly the
first, thoracic somite bear two pair of limbs viz. maxillipeds and pes I, and thus corresponds to two
somites (cf. Hansen 1893).

By examining females from Denmark I did not find any difference from those described except
in the arrangement of the hairs of the ventral surface of the maxillar and maxillular somite, which
is less complex than those figured.

The only difference between males and females seems to be the more prominent median
process of the labrum in the former sex.

Textfigure i.

Catanns finmarchiciis G. Q. Labial lobe seen from

in front witli lamina labialis and serrula 6den-

tata etc. X c. 170.

Textfigure 2.

C. fmmarchicus G. 9- (Stage IV— V).

a. Pes V sin. (stage V) in anterior view X 85.

b. Pes IV sin. (stage IV) in anterior view X 85.

c. Pes V sin. (stage IV) in anterior view X 85.

Y. (St. V). Size: Varying from 2-2 (Egedesminde, Davis Strait), 2-5 (73' L. N. 8' L. E.) — 4-8
mm. (Davis Strait). Gran's specimens (-=- urosome) varied from 2'i — 2'6 and the specimens from due
d'Orleans 3 — 4-5 mm.

This stage, in which I have not been able to distinguish males and females, is easily disting-
uished by 4 abdominal somites of which the second is the longest, 27 as long as the first and 1-4
as long as the anal somite. The mouth-appendages are scarcely different except the maxillulae,
which have only 10 instead of 11 setae in the exopodite. The four pair of natatory legs are scarcely
different from those of the mature female, but pes V differs by fused Ri II — III without indication of
Se II but with the number of Si 7 as usual, and by the fused Re II — III with 5 Si and well
developed Se Re II (textfig. 2 a). Number of secretory pores seem to be alike f^ in pes II — III, but

i6

COPEPODA

in pes IV no secretory pore corresponding to Se i Re III was seen and in Re II f^ III pes V only
a single pore is found at the base of Se 3.

The labrnm shows in lateral view complete similarity to Sars' figure pi. I but has the anterior
process less prominent than in most f-$ examined by me.

Y. (St. IV). Size: Varying from 2 (63° 43 L. N. 0-26 L. E.), (r8 + o-6) = 2-4. (South West
of Iceland), 26 (Davis Strait), 2-8 mm. (64° 56 L. N. 36" 19 L. W.) to 2-9 mm. (Jan Mayeu). Gran's
specimens (-^ urosome) varied from 1-4 — 1-83 and specimens from due d' Orleans from 2 — 3-5 mm.

This stage is easily distinguished by 3 abdominal somites, of which the third one is the
longest, being 1,3 as long as the second one, and 2'6 as long as the first one. The number of setae
in the furca is scarcely different. The antennulae (with 25 segments) and mouth-appendages (including

Textfigure 3. Cal. finmarchictis G. 9- (Stage III),
a. Head from the right. X 85. b. Abdomen from the left. X ^S-

c. Pes II dext. Re in post. view. X no. d. Pes III sin. in anterior view. X no.

e Pes IV sin. in anterior \aew. X no. f. Pes V sin. in lateral view. X 150.

the labrum, exteriorly as well as in oral view) except the L,e of the maxillulae, which only possess
9 setae, are scarcely different from f$. Pes I has the Ri II — III fused and an indistinct articular mem-
brane between Ri I and II; the Re II — III are also fused but in other respects this appendage is
scarcely different. Pes II— III have the same segments fused, the Se Ri II is missing, but Ri has 10
setae as usual; the Re II c\; III have only 5 Si. The pes IV differs from the preceding pair by 8 setae
only of Ri (textfig. 2 b). The pes V is more clumsy than in stage V with undivided Ri with 6 setae
and undivided Re with 4 Si and 3 Se. The inner margin of basipodite II has 3 teeth (textfig. 2 c).
Secretory pores are in pes II — IV wanting in Re III, corresponding to Se i - 2, but found at Se Re II
and at Se 3 Re III; in pes V secretory pores are found at base of Se Re I and Se 3.

Y. (St. III). Size: Varying from 1-4 (Davis Strait), 17 (1-3 + 0-4) (63° L. N. 15° \,. W.) — 2-4 mm.
(Davis Strait). Gran's specimens (-=- urosome) of his stage IV varied from 1-05 — 1-44 and specimens
from due d' Orleans 2 — 2-2 mm.

COPEPODA

17

The body appears more slender than in the preceding stage ; the urosome consists of 2 somites ;
the Se of furcal rami is missing (textfig. 3 a— b). The antennulae, which consist of 23 segments,
extend 3 segments beyond the tip of the abdomen. The antennae and other mouthhmbs except the
maxilhilae, in which the Le has 8 setae and the Re 8, are scarcely different. The lateral outline of
the labrum is as shown in textfig. 3 a alike stage V, but the frontal protuberance is less prominent.
The oral surfaces of the labrum and the labium are in their main structures alike f$.

Pes I = St. IV. Pes II in main features alike St. IV, but Ri with 8 setae and Re II c^^^ III,
which is less slender, with 4 Si only (textfig. 3 c). Pes III is comparatively shorter than II, and the
Re II "Ns III has only 2 Se (fig. 3 d). The pes IV (fig. 3 e) has no seta in basipodite II, 7 setae in
unsegmented Ri and 3 Si + 3 rather short Se in Re. The pes V (fig. 3 f) is represented by a wide
indistinctly divided basal part, which is distally attenuated, and here subdivided into longer outer
branch with at least 3 setae decreasing outwards and a shorter inner branch with 2 fairly long setae.
Secretory pores were with certainty only observed at the base of Se 3 Re II o^ III in pes II — III.

Textfigure 4. Cal. finmarchicus G. 9- (Stage II).
a. In lateral view X 85. b. Pes IV X 225.

Y. (St. II). Size: Varying from o-g (S. W. Iceland), i-i (Davis Strait), 1-3 (i + 03) (Jan Mayen)
— 1-6 mm. (Jan Mayen). Gran's specimens (-^ urosome) of his stage V varied from 078 — i-oi and
specimens from due d'Orleans from 1-4 — 1-8 mm.

The body is more slender than in the preceding stage (textfig. 4 a). The head is sometimes
indistinctly separated from the first thoracic tergite, in addition to which 3 somites are found, of which
the last one only bears a rudimentary pair of legs. The antennulae, which reach about one segment
beyond the tip of the furca, consist of 18 segments only, as the segments proximal to the 11 are more
or less fused. The antennae and mandibulae are practically alike those of the f$. The number of setae of
the maxillulae is comparatively small; I^e has only 6 setae, Ivi I has only 10 spines, basipodite III
has 3, Ri I I, Ri II 2, Ri III 5 and Re 7 setae. The maxillae are in the main features alike the f?.
The maxillipeds are in shape alike the preceding stages, but the Basp. Ill has in the middle only
2 Si, as the basal one is wanting, Ri I has a single seta, Ri II (probably Ri IIcv^HI) is rather elongate

Tlie Ingolt'-Expcdilion. III. 4. 3

i8

COPEPODA

with a median and a distal Si and the following segments are fused with 4 setae. The labrnm is
scarcely different from the preceding stage. Pes I is in the main structured as in the two preceding
stages, but the Si of hasp. II is very delicate, the Ri has a fairly well developed articular membrane
between the Ri I and Ri II c^ III. The pes II is practically alike the pes III of the stage III, and
the pes III alike pes IV (cf. fig. 3 e). The pes IV is alike the pes V of stage III and the pes III
of stage I (textfig. 4 b).

Y. (St. I). Size: Varying from o-8, 0-9 (07 + 0-2) — i-i mm. Specimens from due d'Orleans
were i mm.

The head is more produced than in the following stage without distinct filaments; behind the
head 3 fairly distinct somites are seen in addition to the two somites of the iirosome. The antennulae,
which scarcely reach the end of the urosome, consist of 11 segments only; proximally 3 indistinct
segments are found, the segments 11 — 18 are probably fused and the segments 19—25 are free. The

antennae and mandibulae are
practically as in f$. The nia-
xillulae are alike those of
preceding stage but the number
of setae seems to be somewhat
smaller. The maxillae are in
main as shown in textfig. 5 b
alike f$. The maxillipeds are
even more reduced than in
the preceding stage, as easily
recognised by studying fig.
5 b. The Ri, which is only ^3 as
long as the basipodite III, con-
sists of the long basal segment
with two 2 Si and shorter
terminal segment with 4 setae.
The lateral outline of the labrum and labium are, as seen by comparing textfig. 5 a with
3 a, somewhat different from stage III, the longitudinal series of hairs on the oral surface are in
the main arranged as in the preceding stages, but the hairs are very short. The lamina labialis, the
longitudinal series of delicate hairs in front of it and the serrula sexdentata are scarcely different from
preceding stages. The pes I fig. 5 c has 2 wide basal segments without Si. The undivided Ri has
7 setae and the Re has 3 Si and 3 Se. The pes II (fig. 5 d) is less slender but in other respects alike
pes IV stage III. The pes III is alike pes V stage III. No secretory pores were observed.

Occurrence etc. Calanus /inmarchicus Gunn. was, as there was good reason to expect, found all
over the area explored by the different expeditions. As I have examined a great number of this
species from several hundred of samples, I thought it worth while to examine the proportion of the
different stages in each sample. As tlie number of specimens, which were originally picked out from

Textfigure 5. Cal. finmarchicus G. $. (Stage I).

a. Lateral view of the labrum X 225; b. maxilla and maxillipes X 225; c. pes I

(perhaps somewhat flattened by the pressure of the glasscover) X 225; d. pes II

sin. in anterior view. X 175.

COPEPODA

19

the samples, were not selected from this point of view, and as the istruments, by which the different
hauls are made, are widely different, the results arrived at are only to be compared with caution, and
are not expected to give more than an impression. For getting an exact knowledge of the vertical
and seasonal distribution of a species like Calanus fiiiuiarchicus^ we are obliged to have at our
disposal numerous samples taken with a closing net at the different hours of the day, and in the
succeeding months of the year at the same localities, scattered over a wide area. Most of the samples
at my disposal are surface ones; the vertical hauls are not procured with a closing net. Like most
expeditions in these regions the Ingolf Exp. etc. has only taken plankton samples in the months of
the summer (May to September) and seldom in different months in the same region.

West coast of Greenland. The Ingolf Expedition has in the months of June and July 1895
taken several samples with C. finmarchicus.

Number of samples in which each stage occurred
in 17 samples June and in 15 samples Jul}'.

St. VI

V
IV
III

II
I

a

June

July

0

4

II

13

7

12

9

13

8

12

6

8

4

7

Table showing the proportion, in which the different stages were found.

Station

Temp.
Sur-
face.

Percentage

of different

stages.

Number of

Date 1895.

L. N.

L.W.

of
Ingolf.

Depth in
fathoms.

St.

VI

V

IV

III

II

I

specimens

6

9

examined.

18/6 4 p. m.

60° 29

34° 14

St. 19

Vi 300—0

9°C.

..

31

64

5

100

26/6 2 p. m.

63°3o

54°25

St. 25

V 200—0

29° C.

17

24

19

15

13

12

200

so/e 3 P- m.

63°56 5

52°4i

St. 26

V> 20—0

2-9° C.

I

I

2

14

52

30

130

V7 8 p. m.

65°i7

55°42

St. 28

V 100— 0

i-i5°C.

I

21

57

20

I

65

5/7 3'30 P- m-

65°34

54°3i

St. 29

V 50—0

3-5° C.

03

3

32

22-3

23-4

18

I

340

",'7 8-40 p. m.

66°35

55°54

St. 31

Vi 50—0

2 6°C.

0-3

0-3

18

36

45

0-4

230

f"/; 1 1 p. m.

Holstensborg.

PI. 31

I '5° C.

0-5

2

91-5

2

4

100

18/7 3 p. m.

65°i7

S4°i7

St. 34

Vi 100 — 0

51° C.

4

15

20

30

29

■>■

50

=8/7 7 p. m.

er'so

56°2i

SL 19

V 100— 0

8-5° C.

3

47

47

2

I

" 1

200

The following table shows the number of the mentioned 9 samples, in which a certain per-

centage of the different stages were found.

Stage.

VI

V

IV

III

II

I

Percentage.

0%

0

0

0

I

2

4

0—5

7

2

3

2

2

3

5-10

0

0

0

0

0

0

10—20

I

I

3

3

2

I

20 — 50

I

4

2

3

2

0

50-75

0

0

I

0

I

I

75-100

0

I

0

0

0

0

20

COPEPODA

From the above it is impossible to draw any conclusions except that all stages occur fairly
frequently in the months of July and June. As mature males have been found in four samples (in
addition to the 2 mentioned: ■/;. St. 27. 64°54 L.N. 55°io L. W. V' 200 — o and ^fa/^. St. 26. PI. 25. 63''57
L. N. 52° L. W.), in the mouth of July it is safe to conclude that propagating takes place at that date.
From the North of Greenland Lundbeck and Bergeudal have 1889 and 1890 (^s— %) taken 7
samples, which all contained mature females. The other stages were less frequent. In the samples
from August and September the mature were found in comparatively few samples; in the two examined
samples, with numerous specimens, the stage IV formed the majority.

Lundbeck

1889—90

7 Samples.

Bergendal
6-26/8 1890
8 Samples.

Bergendal
Lundbeck.

Percentage of each stage.

Number of

VI

V

IV

III

II

I

specimens
examined.

VI
V
IV
III
II
I

7

2

4

2
2
2

3
5
7

7
5

I

2

2
2

Lundbeck 6/6 90. 65 "27 L. N.
Lundbeck M V) 1890 Diskobay
Bergendal 6/9 1S90 Diskobay.

53°48 L. W.

20/0

0

35
14

19

60
81

27

5
5

27

25

> 100

> 100

> 100

Mature males were taken by Lundbeck "'/, 89 (57''o8 L.N. 49° L. W.); females with sperma-
tophores ^3/, 89 (59°i2 L.N. 52°05 L.W.I. In addition to these localities, males were taken by Soren
Hansen '7? 85 (59° L. N. 5i°i8 L. W.), and males are mentioned under the name of C. quinqueannulatus
by Kroyer from Greenland.

Denmark Strait. The Ingolf Expedition has ^^Js—^^jb 1895 and ^s/g — ^Sj^ 1896 taken 28 samples
containing C. fuuiiarcliicns. The different stages were distributed in the following way.

U <\i

Date.

Ingolf.

i-r

Long W.

Depth in
fathoms.

Temperat
at surface.

Percentage of each stage.

Number of
specimens.

Percentage
of specimens
in 5 samples.

Number of Samples.

Stage.

VI

•\!

IV

III II

I

VI

d- 9

V IV

1

III

II I

d"

9

<

2
J4

6'/2 p. m.
20/5 1895

St. 9

64° 18

27°IO

V' 100—0

7-9° C

2

28

7

13

23 23

4

c. 200

0

3

2

3

V

18

21/5 1895

St. 1 1

64°34

3I°I2

Vi 200—0

70° C.

I

70

16

5

4

I

2

175

0-5
6 — 10

2

3

2

I

2

2

2

IV

19

8-303. m.

5/6 1S95

St 16

65°28

27°o5

PI." n

8° C

I

27

48

20

4

70

II — 20

I

I

2

III

18

4 — 6 p. m.
■5/6 1895

• ■

63°43

24°20

Cyl. 10

3

6

74

17

86

20—50

I

2

I

I

I

II

9

3 a. m.
=8/6 1S96

St. 96

65°24

29°00

P. 100—0

7-9° C.

1-5

39

58

1-5

64

50—75

I

2

I

5

■•

■•

75—100

■■

■

The S/S Thor has from '^-2% 1904 taken 14 samples containing Cal. /imiiarc/'iiciis with the
young-fish trawl from deep water, in addition to several from the surface, which have been examined
by Paulsen (cf. 1906 p. 10).

COPEPODA

21

The East-Greenlaud Expedition 1900 has in the Denmark Strait from %— "/g between 65°
Lat. North and 62°45 Lat. North, and between 35 and 26° Long. W. taken 50 samples (F. 312—366),
of which 30 contained C. f.\ the hauls were made each second hour day and night at the surface.

0 .

1904.

S/S.
Thor.

L. N.

L.W.

Depth in metres.

Percentage of each stage.

Is-

Percentage
of specimens
in 4 samples.

Number of Samples.

Stage.

1"

VI

V

IV

III

II

I

VI

V

IV III

II

T

c?

9

cf

9

V
IV

9

10

4

"9/6
'8/6

St 152

St. 153
St. 154

St 149

65°oo
65°20
65°27

65°52

28°10
27°I2
27°IO

26° 1 2

Yt. 200 M. Wire
Yt. Soo M. Wire
Yt 15 M. Wire
Yt. 75
Yt 80
Yt. 800
Yt 250

6.5
II

1

4

2
2

57
60

97
92
78
52
58

36

27

7

18
46
40

2

. .

. .

130
100
130
100
175

TOO
80

0

0-5
6-10
11—20
20—50

51—75
76—100

I

3
I

I

3
3

I

I
I
3

4
2

••

From the following list it seems to be fairly safe to conclude that the C. /. in the month of
September is more common at night than in the day time at the surface, and that the stage IV— V is
the most common. In no sample I have examined more than 30—40 specimens; in the few ones
containing that number the percentage of the stage IV— V was greatest. Only a single fullgrown
female was found in a day sample.

Number of

samples in

The time at which samples

Number of

Number of

Stage.

which spec-

were taken by the Danish

samples

samples

imens of each

East-Greenland Expedition

without

containing

stage were

1900 from 8/9 — 22^^.

Cf.

Cf.

found.

VI

8

Taken between 4-05 morning

iS

8

V

25

and 7 55 evening

IV

23

Taken between 8 evening

3

21

III

'3

and 4 morning

II

7

I

7

F'or drawing any conclusion from the material from the Ingolf and the Thor Exp. at the
present time the material is too scanty. But it can not be denied that the percentage of mature spec-
imens is bigger in the August-June samples, and that propagating takes place about the month of
Jime, as fullgrown males or females with spermatophores were found '% 1892 (Lundbeck Dyrefjord),
c. 20/5 1895 and 20/g 1904; no males were found September 1900.

South of Iceland. In the Atlantic south of Iceland from about 28° Long. W. to the Faeroe-
Channel, and as far South as 60° Lat. North, the Ingolf Exj). has 'V5— 'Vs 1895—96 taken about 55
samples containing C./., and in August 1895 — 1896 about 10 samples.

22

COPEPODA

Ingolf.

L. N.

L.W.

Depth

iu fathoms

and net

Temp.

at
Sur-
face.

Percentage of each

stage.

Ji

Eg

Number of samples in
which each staee was

Date.

VI

V

IV

III

II

I

Stages.

found.

.2/5.16/6

d"

9

August

4—8 a. m.
M/6 96

6i°30

27°25

Cyl. 25

8-8° C.

4

■ '

30

60

6

109

^1

5

7 p.m.

14/6 96

St. 83

62°25

28°3o

P. 100— 0

9-2'' C.

. .

10

13

5

22

50

60

J"

25

6

11-50 p. m.

8/6 96

St. 73

62=58

23°28

V. 100— 0

7-3° C.

0-5

6

II

63

19

0-5

135

V

39

10

8 p. m.

8/696

PI. II

8-3° C.

2

38

48

12

217

IV

46

8

9/6 96

St 74

62°i7

24°36

PI. 12

8-3° C.

4

7

81

4

4

100

III

38

5

3-30 a. m.
3l6 96

St. 69

62°4o

22°I7

V. 100— 0

?

15

29

51

5

100

II

30

6

3 a. m.

3/6 96

St 67

6i°32

22°29

PI.

8-6° C.

..

I

49

43

7

71

I

12

4

10 p. ra.

J'/s 96

St 62

63°i8

I9°I2

PI. ID

7-7° C.

20

39

40

I

136

7-30 p. m.

St 63
St 64

62^40
62°o6

i9°o5
i9°oo

V 100

8-3° C.
8-6° C.

31
9

33
49

34
34

V6 96

3 P- ni-

M6 96

A. 16

8

178

¥5 1-

Number of samples.

3 p.m.

St 54
St 55
St 6

63°o8
63°33
63°43

i5°4o

15°02

i4°34

PI. 5
V. 100—0
V. 50—0

9° C.

84° C.

?

2

76

2

28

4

32
21

5

9

27

13

33

21

2

22

2

233

100

168

g.ls

VI

V IV

in

II

I

■«/s 96

■9/5 96

I p. m.

'^/s 95

d-

9

0

15

9

3

1

3

9

3 p.m.
16/5 96

St S3

63°i5

i5°o7

V. 100- 0

8-8° C.

8

10

61

21

70

0-5

2

5

6

2

I

4

3

8-30 a. m.

13/5 96

St 49

62°o7

i5°o8

V. 100— 0

9-3° C.

29

2

7

16

25

21

77

6-10

I

4

7

2

2

3

's/s 96

St 52

63°57

I3°32

V. 200

8-3° C.

I

8

7

10

13

53

8

100

11—20

I

I

2

2

4

3

7 a. in.
20/5 96

St 57

63°37

I3°02

V. 100

8-2° C.

26

26

2

6

19

14

7

50

21—50

I

2

3

8

7

5

4

8 a. m.

20I5 96

St 57

..

A. II

8-5° C.

13

15

32

8

32

50

51-75

3

2

1-30 p.m.
9/8 96

St 133

63°13

II°24

P. 100— 0

10 8° C

••

5

88

7

••

403

76- 100

I

I

I

The Thor Expedition has in 1904, south of Iceland, taken 1 sample in May, 5 in July and 2 in
September.

<i!

Number of samples.

1904.

s/s.

Thor.

L. N.

L.W.

Depth in
metres.

Percentage of each

stage.

OS

^As-

'■''It

'■V?.

VI

V IV

III

II

I

1- «

.S.e
s a

.2 S.

dr

9

/5 "

d"
9
V
IV

I

3
5

5

2
I

I

V9

St 171
183

285

63°46
6i°30
62°49

22°56

i7°o8
i8°46

?
Yti8ooM.W.
Yt 100M.W.

II
I

2

52
90

89

37
9

..

70
500
100

III

I

II

I

I

The East Greenland Expedition 1900 has south of Iceland (62°— 60° Lat. N., 21°— 8° Long. W.)
from 23-28/^ (F 367 — 430) taken 63 samples of which 22, contained C./., but only a few specimens, seldom
20 and only once 46.

COPEPODA

23

In addition to the localities mentioned, specimens in propagating have been found by Lundbeck
'«/5 1890 55°25 Lat. N. ag^os Long. W. (5 c?; 25?; 5 (V); 15 (IV); 5 (III); i (II)), "/^ 1893 between Talkna
and Arnarfjord (i fc?; 8 ?; 2 (III)).

Stage.

Number of samples
containing the dif-
ferent stages.

The hours at which the

samples were taken by the

Danish East-Greenland Exp.

1900 23-28/g

Number of

samples

without

C.f.

Number of
samples

4-05 a. m.
— 7-59 p. m.

8 p. m.
—4 a. m.

containing
C.f.

VI
V
IV
III
II
I

7
7
4
4

7
7
5

Taken between 405 morning

and 759 evening.

Taken between 8 evening

and 4 morning.

29

12

12
10

By S/S Thor several males and (St. 183) once females with spermatophores were found in July,
and even '/g- By the Ingolf Expedition it has been found propagating in several samples from May
1896 and % 1896 (Cyl. 12 62°i7 Lat. N. 28=03 L. W.).

When the material collected in May— June is compared with that collected August and September,
one is struck by the fairly equal representation of the different stages in the spring, and by the pre-
ponderance of the stage V— VI in the August— September samples. When the difference between day and
night-samples is compared with that from Denmark Strait, it is seen to be less marked; in the number
of specimens of the different stages no marked difference was found day and night.

Iceland-Faeroe-Channel. The Ingolf Exp. has South-East of Iceland in May 1895—96 taken 9
samples containing Cal. f, and in August 1896 7 samples.

Number of
samples.

L. N.

L.W.

Depth

in
fathoms.

Temp.

at
surf.

Percentage of each stage.

'o «

Stage.

T»ofc. ■ ^

VI

V

IV

III

II

I

%\

May
1895-96

Aug.
1896

Eu

6

9

zs-

^Wi

9 /
V
IV

III
II

I

4
II
8
5
5
5

3

I
5
7
7
4
3

3

'V5 95 2'AP-n>-
'Vs 95 5 P- m.
"/s 95 « P- m-
20/5 96 9 a. m.
10/8 96 7 p. ni.
io'8 96 10 p. m.
10/8 96 2-30—
4-30 p. m.

St. 4

St. 2

St. I

St. 59
St. 139

64°o7
63°04
62°3o
65°oo
63°36
63°45

63°3o

II°12
9°22
8°2I

1I°26

7°30
7°25
7°4o

V.I 100— 0

V. 30- 0

V.I 50—0

A. 12

A. 80

A. 81

Cyl. 40

9-5° C.
10° C.
1-5° C
9° C.
8-5° C.

io-s° C

2

0-5

95
79-5
25
98

2
45

5

I
4
18
2
20
47
13

4
20

49
'9

I

2

24

14
15

I

5
12

13
10

5
0

2

4-5

100
100
100
100
100
100

From the Thor expedition 1904 I have only examined specimens from 4 samples, 3 containing
males or eggs.

5/5 04. St. 63. 64°o5 Lat. N. 0=38 Long. W. Yt. 300 M. Wire 7 f? (2 with spermatoph.); 3 fc?; 2 V.
9/5 04. St. 70. 63°35 Lat. N. 6°20 Long. W. Yt. 100 M. Wire i7%fc?; 80% f? (if? with sperm.); 3% V.
"/s 04. St. 99. 6i°i5 Lat. N. 9=35 Long. W. Yt. 100 M. Wire 90 '^/of? 10 "/o V.

24

COPEPODA

My material from Ingolf and the few samples from Tlior confirm Paulsen's result that the
propagating in this region takes place in the beginning of May. It is rather curious that a single male
was found in September. Compared to the May samples those from September show a preponderance
of Stage IV— V.

South-West of the Faeroes. In the Atlantic, South-West of the Faeroes, about 8 samples with
C. f. were taken ^o/j— 2&/6 1905 by the Thor.

"MiiiTiber

j

Stage.

Number

Stage.

of

1905-

Thor.

L. N.

L. W.

Depth in

VI

V

of spec-

samples.

d

9

imens.

<S

3

9

7

*/6 05

St. 72

57°52

9°53

Yt 600 M. W.

8

92

50

V

6

"l6 05

St 90

47°47

8°oo

Yt. 300M.W.

15

60

25

75

IV

I

In addition to the two mentioned localities a male was found (^Yo 49° L- N. 12° L. W.), and
females with spermatophores (^"/^ 59°49 L. N. 8° L. W.). Propagation accordingly takes place as far
South as 47° Lat. North "/(,. In this connection ought to be mentioned that the S/S Thor (St. 223 B.
'7/3 1904) at Thyboron, Denmark, has taken 50 f?, 5 fj", 10 (\^, I (IV); and that Rink '73 1858 has
taken i f <?, 12 f?, 16 (V), 5 (IV), i (III) at the Orkney Islands.

South-East of the Faeroes. The Ingolf Expedition has South-East of the Fseroes, as far South
and East as 57°53 L. N. 7°39 L. E. from 5-7/j 1895 and 4 '75 1896, taken 10 samples containing C. /.,
and from "^'S/s ^^95 ^""^ '"'/s 1896 9 samples; they were almost all taken with Cyl. and contained
generally 10—30 specimens (cf. tabula).

Number of
samples

Number of samples
containing each
stage taken by

The hours, at which samples

Samples

Stage.

from
Ingolf.

0.Exp

Night

8 p. m.

—4 a. m.

. 1900.

Day

4 a. m.

—8 p. m.

were taken by East-Greenland
Exp. 1900 =9-30/9.

without
C.f.

Samples
with C.f.

May.

Aug.

VI

6

I

2

Taken between 4-05 morning

IT

4

V

6

8

0

4

and 7-59 evening.

IV

7

6

2

Taken between 8 evening and ; g

o

HI

8

2

4 morning. ]

11
I

5

5

I

In the May samples from the Ingolf the different stages seem to be equall\' well represented
in contrast to those from August, in which the stages IV — V are best represented. In this region the
Thor has in 1905 collected some fullgrown males viz: i f J", 2 (V) (^7? ^9°5 St. 120 59°54 Lat. N. i°i9
Long. E.), I fd", 2 (V) ('7/7 1905 St. 119 59°54 Lat. N. 4°oo Long. E. Yt. 500 M. W.), i f d", 15 f?, 12 (V)
('/g 1905 57°33 Lat. N. 4=26 Long. E.).

The East Greenland Expedition 1900 has %— 3% (59°33 L. N. to 59° L. N.; 3°24 L. W. to o°o5
L. W.) (F: 431 — 453) collected 23 samples, of which only 4 day-samples contained a few specimens of
C.f. (cf. tab.).

COPEPODA

25

VI

17

V

26

IV

26

III

22

II

14

I

7

Norwegian Sea. The East Greenland Expedition has from "^/e—^'^k 1900 crossed the Norwegian
Sea from 6o°26 Lat. North, 3°io Long. East to 69°o6 Lat. N. 6°i2 Long. West. In the samples taken
with the net F. (F. 1-89) 79 were found containing C./ but only 5 without any specimens. In addition
to these, 5 samples, taken with a closing net and 6 samples with net A and B were taken. The pro-
portion between the different stages in 39 samples from the whole region which were examined in

this respect was a follows.

VI 17

The number of samples

(altogether 33) in which each

stage occurred.

No males were found at the surface in the explored region. As I have unfortunately not
examined the proportion between the stages in all the 79 samples, and have not with security classified
the larval stages, the following remarks are set forth with due reservation. In the more southern part
of the region (to 64° N. F. 38) the stage IV— V were fouud in 14 samples of 16, the f ? only in 4
(1-2 specimens) [F. 27: 10 (V), 6 (IV|; F. 29: 8 (V), 16 (IV)]. In a few samples (between 64° N.-65° N.)
the younger stages were well represented f. inst. [F. 51: 4 (V), 20 (IV), 20 (III), 18 (II), n (I); F. 52:
2(V), 10 (IV), 14(111), 10 (II), 20 (I)].

In 10 samples taken between 67° L. N. and 69° L. N. (F. 62—81) f? were found, in fairly big
numbers (5—10), but only in a single one of these (F. 64 6 f?; 2 (V) i (IV)) stage IV-V were found and
in another stage I --II (F. 66 2 f? 5 (II), 15 (I)); in the latter sample as well as in most of the ten
mentioned above and in several others often large numbers of eggs and larval stages of Calanus, certainly
of Cal. finmarchinis, as no Cal. hyperboreus was found in this region, were observed. It seems to be
probable that propagation took place in this region c. ^V^ 1900, in a similar way, as Dam as has
found out with a more southern and eastern region. Whether the propagation between 62—67° Lat. N.
has taken place at an earlier date, or if the juniores there fouud are born in the region explored by
Dam as, it is at present impossible to tell.

Near Jan Mayen. In the ocean tract passed by the Danish East Greenland Expedition from
28/6 II p. m. 1900 to 9/^ 9 a. m. from near Jan Mayen to 74°i5 Lat. North i2°2i Long. West (F. 91 —
F. 243) about 145 samples were found, of which ouly 4 contained a few specimens of C/ viz. F. 92
^8/6 II p. m., F. 96 30/6 4 a. m. and F. 91 ^s/o ii p. m. with 5 f?, 2 (V), i (HI) near Jan Mayen, and
F. 143 ^,'7 8 a. m. 72^30 L. N. 0=41 L. W. i f?. In the samples F. 153—243, which were taken between
scattered ice or along the ice-edge no specimens of C. f. were observed, but 17 samples with a few
specimens of C. hyperboreus. A few vertical hauls in the region near Jan Mayen show that the fauna
of C. f. in deeper waters was probably richer.

25/6 1900 Jan Mayen 50—60 f.

25/6 12 a. m. at the surface

12 p. m.

1/7 I p. m. Closing net

100—50 f.

50—25 f.

300— o f.

21
10

5
12

I
I

I

56
8
2

II
3
3
3

IV

14

III

The Ingolf-Expeiiitlon. III. 4.

26

COPEPODA

It is worth noticing that a fc? was found between 50 — 25 fathoms. In this connection it may
perhaps be of some interest that Johannes Petersen "/^ 1901 73 Lat. N. 8° Long. E. caught a
big sample consisting almost exclusively of C.f.: the proportion between the stages was the following:
f? 52%; V 42-5%, IV 3%, III i°/o, II 0-5%, I 1%.

Jan Mayen to East Greenland. From 9/^ 10 a. m. to '7'^ 5 a. m. taken in the sea north-west
and west of Jan Mayen between 74°28 Lat. N. i5°03 Long. W. and the coast of East Greenland at
70°29 Lat. N. 2i°2i Long. W. I have examined 13 samples (F. 244 — 262), of which only 5 contained
C.f. viz. St. VI in 3 samples, IV in i, II, in i, I in i.

East Greenland. The East Greenland Exp. has, near the coast of Greenland, taken some samples
containing C.f. in vertical hauls, viz.

10/7 6 a.m. 1900 72°2S Lat N. 15*^30 Long. W. Closing net 6— o f
6 a. m.

■''(^ 1900

29/7 1900 Stewards country

28/8 1900 Forblas Fjord

28/7 1S91 E. Bay. 72°25 Lat. N. I9°56 Long. \V.

120— o f.
Closing net no — \o f.
— 35-10 f.

VI

V

IV

3

9

2

I

12

10

6

I

1 ^

18

1 ^

I

I

70

30

III

On the voyage home between Forblas Fjord,* Antarctic harbour, and 70° L. N. 18° L. W. from
30/3 9 p. m. to -/g 9 ^- !"• 190° ^'^^ East Greenland Expedition collected 20 samples (F. 265 — 278), of
which 12 night samples contained C. f. in different stages, while 4 day samples only contained a few
specimens (SL I— II), and the remaining 4 nauplii onl)-.

Stage.

8 p. m.
4 a. m.

3 a.m.
7 p.m.

Date.

0. Exp.
1900.

Percentage of each stage.

Number
of spec-
imens.

Naupl.

eggs.

VI

V

IV 1 III 1 II 1 I

VI
V
IV
III

2

2
4

9
8
8
12
5

3
3
8
0

3°,'8 10 p. m.

1 1 p. m.

3i|8 8 p.m.

F. 266

F. 267
F. 277

Forblasfjord

1-5

3

9-5
6

3
II

10
49
49

32
16

25

44
15
26

75
85
50

c

c
c

c

II

I

Nauplius
Eggs

Taken bet

3 a. m.-7

Taken bet

8 p. m. and

ween
p. m
ween
4 a. I

u.

4
0

•/•

I
i;

\
>

The vertical hauls show that stages IV — V of C.f. are fairly frequent in the month of July.
As no Cal. hyperboreus were found in any of the samples, and as the'younger stages of Cojjepodites of
C.f. were common, there is every reason to regard the nauplii and eggs found in large numbers all
over the surface as belonging to the same species. Accordingly there is no reason to doubt that an
important locality for the propagation of C.f. is sometimes found in this region. The few samples
and the small number in which the f$ were found suggest that the f?— c? are either exstinguished
or living in deeper strata.

COPEPODA

27

North of Iceland. The East Greenland Expedition has in the region crossed from ^/g 10 a. m.
to 4/g TO p. m. between ca. 70° L. N. and 67° h. N. and between 17° L,- W. and 23° L. W. taken 27
samples (F. 284—310), of which only 8 (taken in the night) contained C. f.

Numt
samp]
whicli

er of

es at

each

0. Exp. 1900.

Number of

samples with

C.f.

Date.

Net.

VI

V

IV

III

II

found.

-5-

+

VI
V
IV
III
II
I

2

5
4
2

3
2

Taken between
3 a. m.— 7 p. m.

Taken between
8 p. m. — 4 a. ni.

17
2

0

8

3/9 10 p. ni.
ID p. m.

4/q 2 a. m.

F. 299
F. 300
F. 301

c. 68° L. N.

i7°L.W.

•

I
I

4
17
21

2

I
21

I

The contrast to the previous group is well marked by the preponderance og stage IV— V, and
by the fact that no nauplii were found (cf. p. 21 about their occurrence in Denmark Strait).

The Ingolf Exp. has from '77~V8 1^9^ collected 9 samples with C.f north and east of Iceland
(as far south as 0.65° north) and 17 from '° -25/^ between Jan Mayen and north-east of Iceland (in-
cluding St. loi, 121 and 107).

In 9
samples

In 17
samples

10-25/7.

1896.

Ingolf.

L.N.

L. W.

Depth
at fathoms.

Temp.

at
surface.

Percentage of each stage.

°3

Stage.

VI

V

IV

III

II

I

6

9

S. p.

^jvi

V
IV

III
II

I

0

4
7
7
7
6
6

I

12

8

14

12

12

9

2/8 96 10 p. m.

10/7 4-30 p. ni.

10/7 5 a. m.
11/7 4'2o a. m.

25/7 II a. m.
''•h 3 "3° P- "1-

St. loi
St. 102
St. 104
St. 120
St. 117

66°4o
66°23
66°23
66°23
67°29
69° 13

22°I5
I2°05
IO°26

7°25

1I°32

8°23

A. 73
V2. 100— 0
V^. 100—0
P. 100—0

V2. 100— 0
V2. 100 — 0

7° C.
5-5° C.
4-3° C.
6-3° C.
5-1° C.
41° C.

2

20
84

1

0-5
20

30

9
16

1

0-5
75

45
20

6

20

2

20
35

16
49

3

14

55

28

2

2

21

2
1

75

150

50

75

133

150

The S/S Thor has in 1904 taken two samples with C.f. viz. «/^ St. 214 67°i9 L. N. I7°55 L,. W.
Yt. 800 M. Wire 4 f?, 14 (V), and ^3/^ 1904 St. 216 66°i5 L. N. i2°i3 L. W. Yt 6cxd M. Wire i (V). As a
fc? was taken "/^ 1896 and by the East Greenland Expedition near Jan Mayen 7? 1900, and as Cope-
podites of stage I — II and nauplii of C.f.l were taken at several stations, there is reason to think that
propagating takes place in this region in the month of July.

Distribution etc. About the distribution of Cal. finmarchicus I refer to the able account of
Farran (1911). It has "been recorded from the South Atlantic off Cape Colony, the west coast of
North and South America, the Mediterranean, the Adriatic, the Red Sea and the Polar Ocean." In
the Pacific it has been found abundantly by Ester ly in the Bay of California. „In the North Atlantic
it is distributed over the whole of the area north of about 55° N." It is sometimes found in great
numbers along the east-coast of North America and is, to the east, distributed as far as the western
part of the Baltic.

4

28 COPEPODA

To deal with the vast topic of its seasonal occurrence in the area investigated by the Inter-
national Commission does not fall within the scope of this paper, and has fortunately been as well
done by Far ran as the in several respects incomplete material allowed. As, however, the important
contributions to the biology of Cala/iiis finmarchicus by Dam as. Da mas & Koefoed and especially
by Paulsen are based upon material from the regions investigated by the Ingolf Exped., and as all
the conclusions, to which these authors have arrived, do not quite stand criticism in details, I feel
obliged to deal rather exhaustively with these papers.

About the vertical distribution of the different stages it seems to be a general rule, that the
younger the stage of development the nearer the surface do the specimens live, as pointed out by
Damas, Paulsen and Far ran; the fullgrown females and males are generally spawning on the
surface in every case in the northern seas, as set forth by Damas & Koefoed, who write (1907
p. 393) "lya ponte de Calaniis Jinniarchicus s'opere visiblement a une profondeur d'autant plus grande
que la region consideree est plus meridionale. Par la meme, la distance de la cote ou it se reproduit
augmente progressivement; autrement dit, cette espece prend un caractere oceanique de plus en plus
accentue." About the vertical distribution of the C. /. within the day I have only found observations
by Esterly, who writes (1911 pp. 140 — 151) as his conclusion:

i) C. /. is most abundant at the surface about 7—8 p. m. during June and July.

2) It has begun to leave the surface by midnight and is most abundant at a depth of 5 — 10
fathoms about midnight.

3) The jDlurimum during the day (6 a. m. — 6 p. m.) is probably 200 feet.

He thinks that the effect of light upon the "geotropisme of animals is probably the main factor
involved". On a much bigger material (1912, pp. 282 — 95) he arrives at almost the same result.

Unfortunately he has not examined the part which the different stages play in these diurnal
migrations.

My material was not well adapted for solving this question, but the difference in the number
of specimens taken by the Danish East Greenland Expedition in Denmark Strait (^3~^79) ^^- '^^b- P- 21,
from North-East Iceland (^"Vg)) but especially from East Greenland (cf. tab. p. 26), indicate that all stages
inhabit the surface-layers in the night in some regions and at some seasons, in which only the
youngest Copepodites or the larves are frequent in the day.

It must accordingly be admitted that there is a source of error in comparing the relative
proportion of the different stages contained in surface samples, as Paulsen has possibly done, as he
does not state whether the hauls are made in the day or in the night.

It may perhaps be allowed to set forth one more general remark against Paulsens con-
clusions, that they are often based upon a too scanty material; even if, f. inst., five samijles from a
certain region show almost the same proportion between the stages, it is not at all inprobable, that
the next 5 will show quite another result.

Paulsen thus summarises (1906 p. 7) his results based on the Thors material from April 1904.
"In April, there are many adult Calamis finviarchiais and Naiiplii at the surface of the sea to the south
of Iceland, many Natiplii (Sample 10) west of Iceland likewise on the surface. North of Iceland
there are but few adults atid probably wo junior cs. Along the east coast of Iceland C. f. seems for

COPEPODA 29

the most part to be absent." On p. 6 "I thns ventnre to conclude that stage III [my IV] has been
predominant along the west coast of Iceland in April". Only 2 samples (7 and 9) bear out this
opinion; sample i but especially 10—12 (taken same date and locality with different nets), when
rightly interpreted, shows the species in propagation. The conclusion, as far as the North is concerned,
is based on several hauls with negative result and 2 samples taken with young-fish trawl and with
c. 95°/o f?; to bear out this conclusion much more material is needed.

His conclusion for May reads. "Whereas the Atlantic and the waters between the Faeroes
and Iceland are rich in C. f. the waters on the east and north coast of Iceland are poor, of the west
coast we know almost nothing." The Ingolf material from May and June 1895—96 (cf. tab. pp. 20—22)
confirms this view, and shows the species in full propagation especially in the latter half of May. The
same is the case in the middle of Denmark Strait. Paulsen's conclu.sion from north Iceland is placed
on far too scanty material.

Paulsen's conclusion for June reads. "To the south and west of Iceland there are great
quantities, mainly jufiiores, — west of Iceland considerable quantities of adult both c? and ? . . . On
the western part of the north coast of Iceland, where the water is warmer, many juniores were also
found, on the eastern part, where the water is colder, few or none" (1906 p. 12). The Ingolf material
(cf. p. 22) from the south of Iceland confirms the conclusion that the juniores predominate; the great
number of St. I— III probably indicates the new generation. My own samples from the Thor and in a
less degree from the Ingolf (cf. p. 20) tell the same story as far as the west coast is concerned. Paulsen
thinks that the adult males and females probably belong to the new generation, "as they occur along
with a number of juniores, most of which are in the larger stages". This proportion between the
stages, which f. inst. is not found in a sample 1 Ingolf St. 9 ^o/^), seems just as much to speak for
referring them to the old as the new generation. The hauls from the north coast are so few, that it
must be admitted that our knowledge about the occurrence of C.J. in the month of June is too
incomplete for any conclusion as far as this region is concerned.

The author writes (1906, p. 13). "Summarising the conditions in July we find that Calanus
finmarchicHs has increased more in the south than in the north, and that individuals on the easterly
north coast are larger than those of the westerly north coast on the one side, and than those on the
east coast on the other." The greatest number of specimens of the south coast belong to the stage
V— VI; Paulsen's suggestion that deep hauls with the young-fish trawl would show a considerable
amount of males is shown to be right by tab. pag. 22; whether these specimens belong to the elder or the
new generation is impossible to tell. The two samples (Nr. 3—4) from the north western coast do
not allow any conclusion, but the preponderance of St. IV (50—90 "/o) in 9 of 10 samples, scarcely
without any adult, is very remarkable, but does not give any information about the origin of the
specimens; 4 samples from the east coast show not much similarity to each other or to 2 samples,
from the Ingolf (St. loi — 102) with a considerable number of adult specimens. Paulsen concludes (p. 14).
"As there are practically no Calani on the greater part of the North coast at the end of May and
beginning of June, and as Nielsen has shown with certainty, that the water here is renewed from
the west, we are entitled to conclude that the large quantity of Calani on the north coast, as also
the young of the cod, have come with the Irminger current from the west." Before accepting this

4

^L rf 'A'

w

30

COPEPODA

theory, a niiicli larger number of samples from May and June must be examined. Personally I think
that surface plancton like the Nauplius of C. f. are carried by the current from the south to the
north, increasing in size during the carriage, but also that not the smallest amount originates where
it lives, and begins to prosper when the Atlantic current makes its influence felt. Paulsen's con-
clusion that from August stage V is predominant south of Iceland is proved by a big and varied
material; a few samples taken by the Ingolf south-east of the Faeroes and of Iceland tells the same story.

Paulsen has from the month of September examined a few samples from the north coast
with St. V in the majority. Samples taken by the East Greenland Expedition north-west of Iceland,
in Denmark Strait and south of Iceland tell the same story.

Damas has in his interesting paper shown that the propagating of C.f. took place ^i-jo/g 1904,
south of 67° ly. N. where the Atlantic and the North Polar current meet. The material brought home
by the Anidrup Expedition tells exactly the same story for "J-^t/o 1900, but as far north as 69° L,. N.
Damas suggested that the majority of the specimens of C. /., which inhabit the Northern Ocean
took their origin from this region, and, by the Gulf-Stream, were scattered all over the ocean. He
writes (1905 p. 19) "II est done extremement probable que nous avons par la reconnu le chemin suivi
par le reuouvellement printanier des Calanides et I'origine des masses considerables de Calanus qui
peuplent en ete le Nord de I'Ocean et y jouent un role si important." Gran had, however, in his
well known paper (1902 p. 64), found the C. /. in full propagation on the north-west coast of Norway
in April — May, Paulsen has from Lofoten examined specimens in propagating from ^^j — 16/^ 1899
and Damas and Koefoed (1907 p. 390 — 391) have found it spawning not only along the coast of
Norway but also in the fjords of Spitzbergen {^^-^^jf, 1905). The Due d'Orleans has taken C. /. d*— $
near Cap Bismarck (76°49 L. N. i8°i3 L. W.) ^7/7 1905 *" a depth of 100 meter, 31/^ at St 42 (78°o6
L.N. i5°o6 L. W.) 44—280 m. C. f. was found cc (J*-?) and at St. 47 (76°47 L.N. i5°2i L W.) ^s
60 — 170 meter C.f. was found cc (c? — $). Even if no eggs or larvse were found together with the
adults at these localities, their presence confirms my view that propagation of C. /. sometimes takes
place on a large scale on the east coast of Greenland.

Paulsen suggests in his concluding remarks "that the spring is perhaps not the only repro-
ductive period of Calanus /mmarchicus, for the reason that we also find the adults of both sexes at
other times of the year almost everywhere, where fishing has been carried out in deep waters".

In this he is probably right. He agrees with the different authors "that this species has its
principal reproductive period at any rate in the spring" (1906 p. 19). He is only right, if the spring
is defined as the period at which the waters reach a certain temperature and salinity, and which
varies according to the latitude from March (February?) to August (East Greenland).

2. Calanus hyperboreus Kroycr.
(Plate I figs. I a — d; textfigs. 6 a — b).

1S3S. Calanus hyperboreus n. sp. Kroyer, pp. S4, tab IV, fig. 23. 1898. Calanus bj'perboreus Kr. Giesbrecbt & Scbineil,

1842-45- — — Kr. — pi. 41, figs. 2 a— g.

1S49. - _ Kr, — pp. 542-54:, 559.

1892. — — Kr. Giesbrecbt, p. 91, taf. 6— S.

189S. — — — Aurivilllus, pp. 88— 89.

P- 15-
1S99. — — — Th. Scott, pp. 90-91.

1897. — — — Vanhuften, p. 27S.

COPEPODA

31

1900. Calaiius hyperboreus Kroyer, G. O Sars, p. 2.

1901.

1902.
1902.
1903-

1903.

1903.
1904.

Th. and A. Scott, pp.

338—339-
Th. Scott, p. 450.
Mrazek, pp. 506 — 507.
Jensen, Johansen, Le-

vinsen, p. 303.
G. O. Sars, pp. 12 — 13,

pi. V.
Norman, p. 135.
Wolfenclen, pp. 112.

1905. Calanus hyperboreus Kroyer, Th. Scott, p. 221.
1905. — — — G. O. Sars, p. i.

1907. — — — Damas & Koefoed, pp.

352— 35S, 405.

1908. — — — Farran, p, 20.

1908. — — — V. Bremen, pp. 8—9,

fig- 3-
1911. — — — Farran, pp. 89—90.

1913. — — — Stephensen, p. 71.

1913. — — — Stephensen, pp. 307 —

30S.

Description. f$. Size varies from 7-5 — 9 mm.

The number of secretory pores differs from that of Calanus finmarc'nicjis by the presence of
a "secretory pore", (not in all specimens, as far as I was able to find out) laterally a little removed
from the base in Re III pes II in stead of corresponding to the wanting Se I; in pes III — IV the
pore was found at the same place as in Cal. finmarchiciis, but was more distinct.

In the serration of the second basipodite of pes V it is, as shown by Giesbrecht (taf. 8 fig. 21, 23),
distinctly different from that of Cal.firimarcliictis^ in which species a serrated lamina is found; in Cal.
hyperboreus the number of teeth are smaller (abotit 25 — 35) and they ar not fused basally.

As far as the shape of the labrum etc. is concerned I refer partly to the description of the
preceding species; only a few minor differences are dealt with here. The anterior process of the labrum is
more produced (text-fig. 6 a (d)). In the longitudinal series on the
oral surface (figs, i a — b) the two first groups are seen to be fused and
are diverging towards the free margin. In front of the lamina
labialis no granulation was observed.

Behind the lamina labialis (fig. i c) and between the serrtila
bidentata a dense group of hairs, medially more like short spines is
found; the arrangement is, as seen in the figure, somewhat different from
that of Cal. finmarchicus G. Behind, the group is separated into
two, of which the inner is continued between the lobi labiales, while
the outer is continued on the anterior surface of the lobe and thus
fused with the inner series of the lobes. The labial lobes (fig. i d),
bear 4 — 5 longitudinal series, of which the inner is the longest and
has the longest hairs; behind they are more or less fused with the
group between the lobes. Behind the transverse list, between the
mandibular and the maxillular somites, laterally on each side are found two groups of hairs, forming
together a semicircular figure. Between these groups, in the middle, a group, which is in front triangularly
pointed and behind the transverse line, which probably indicates the limitation between the maxillar
and maxillular somites, is widened out and divided into two portions, between which a triangular
median group of dense hairs is found. More posteriorly a square group of densely placed short setae is
found in addition to one of fewer hairs just in front of the hinder limitation of the maxillar somite.
Laterally as seen in fig. i d a few groups are found.

Textfig. 6 a — b.

Calanus hyperboreus Kr.
6 a. Head in lateral view. X 85.
e. First abdominal somite. X 85.

32

COPEPODA

Y. (St. V). Size. 6 — 6-8 mm. (4-5 + 1-3).

This stage shows the same differences from the mature females as in Cal. fhiiiiarc/iiciis G.,
it differs from that species, as in the adult females, by a pointed lateral corner, fewer teeth in the basipod. II
l^es V marginally, by larger size and greater transparency.

Y. (St. IV— I). Size, of St. IV 37 mm. (g-g + 0'8) — 4-5. Difference from Cal. finmarchicus as in
preceding stage, but number of spines at inner margin of basipodite II pes V 2 — 3. The stage III, which
varies in size from 2'6— 3 (2"4 — 0-6) mm., the stage II, which varies from 18 — i-g mm. and the
stage I, of which I have not examined any specimen, seem only to be distinguished from the corre-
sponding stages of Cal. finmarchicus by larger size, as the character found in the pointed lateral
corner is wanting.

Occurrence. Specimens of Calaiins /lypcrbornis have been taken all over the area investigated
by the different expeditions as far south as 51^00 L. N. ii°43 L. W., the S/S Thor has '5/o 05 taken
a single f?. (St. 82. J t. 1200 M. W.)

West Coast of Greenland. On the west coast of Greenland it has been found by the Ingolf
Expedition from ^^6— 'V7 95 i" ^o samples in the depth of 200 — o fathoms. The stage IV has been
found in the greatest number of samples, but the stage V in the largest numbers; of the adult
females and stage III only single specimens were found; the youngest Copepodites seem to be wanting:

Stages.

Number of

samples in

which each

stage is

found.

Number of

specimens

examined in

ID samples.

Date
1895.

'0

L. N.

L. W.

Depth in
fathoms.

Temp.

at
surface.

Percentage of
stages.

Number of
specimens
examined.

VI

V

IV

VI
V

IV
III

4

8

9

3

6

200

30
10

^5/695
"/695

St 24

St 22

63°o6
58° 10

56°oo
48°25

V.' 200—0
V.' 200—0

4-2° C.
5-4° C.

I
5

96

88

3

7

105
65

Bergendal has at Jakobshavn ^'/s 1890 taken a single f$.
Lundbeck has from '9/5 1889. 58°2i L. N. 48°43 L. W. i f?.

from 23/5 1889. 59°i2 L. N. 52°05 L. W. 3 f?, 3 V.
26/5 1890. 57°o8 L. N. 49°o4 L. W. 10 f?, 10 V.
Soren Hansen "V? 1885. 59°i4 L. N. 5i°i8L.W. 4 V, 10 IV.

Eberlein '2/7 1882. Umanakfjord. i f?, 4 (V), i IV.

Denmark Strait. The Ingolf Expedition has south-west of Denmark Strait (between 62°
L. N. and 58° L. N. and between 40"^ L. W. and 26 L. W.) '^6 1895 and from '76—^% 1896 taken
4 samples of which 3 contained together 6 f$, 3 respectively 12 V and 9 IV, and only 2 samples
containing 3 specimens of stage III. The same expedition has in the Denmark Strait ^^6 1896 taken 5
f? and 25 V, 4/5 1895 I f? and ^Vj 1895 3 V - 3 IV.

The Thor has from '^^ly-^ 1^04 in Denmark Strait in 6 of 7 samples collected 180 f? and
104 V, but in 4 of 7 samples only 10 IV. At St 154 "/^ 67°27 L. N. 27°io L. W. the percentage of
196 specimens examined was f$ 67 %, V 30 % and IV 3 °/o-

COPEPODA

33

South of Iceland. The Ingolf Expedition ha.s south of Iceland 's/^ 1896 St. 68 taken 2 V and
'8/5 1896 St 54 3 f? + 3 V. The Thor has ^Vs 1904 (St- 104, 62°47 L. N. i5°o3 h. W. Yt. 1500 M.
Wire) taken 25 f? and "/? 1904 (St. 183 6i°30 L. N. i7°o8 h. W. Yt. 1800 M. W.) taken 20 f?, 10 V
and I IV. As the Danish East Greenland Exp. from «-^% 1900 has taken 50 samples (F. 312—366)
at the surface from Denmark Strait and 63 (F. 367—430) in the Atlantic Ocean south of Iceland
without any specimens, it is certainly right to conclude, that C. hyperboreus is only seldom found in these
regions at the surface.

Iceland-Fseroe Channel. In the Iceland-Fseroe Channel the Ingolf Exp. has from "-'% 1895
taken 3 samples of which 2 together contained 8 f? and 2 V, one contained a single IV and one 3
III; 19 f? and 29 (V), contained in 4 samples, taken from 'S-^i/, 1896, were examined, but only 4 IV
(found in 2 samples) and a single (III). The Thor has 5/5 1904 (St 63, 64=05 L. N. 9=38 L. W. Yt 300
M. Wire) taken 10 f?, 10 (V), i (IV), ^V, 1904 (St 99, 61=15 L. N. 9=35 L. W. Yt 1000 M. Wire) 16 f?
+ 7 (V) and 9/5 (St 70, 63=35 L. N. 6°20 L. W. Yt 100 M. Wire) 175 f?. From 4/3 1904 (St. 230, 63=10
L. N. 7=31 L. W. Yt 1200 M. Wire) i f ?, i V and i IV were found. As far south as 57=52 E. N. 9=53 L. W.
Yt 1500 M. Wire the S/S Thor has s/^ 1905 taken 16 f? + 20 (V).

North Coast of Iceland. The Ingolf E.xp. has on the north-west coast of Iceland collected a
large number of Cal. hyperboreus ^7/^ 1896 St 125 with the stage V in majority; north-east of Iceland
as far north as Jan Mayen 11 samples with C. h. were taken from ^°-^'<l^ 1904; 7 of these contained
f?, 7 (V), 4 (IV), 3 (III) and 2 stage II; in all samples but one the stage IV— V formed the greatest
percentage.

Date.

Ingolf.

L.N.

L.W.

Depth in

fathoms.

Temp.

at
surface.

VI

V

IV

III

11

Num-
ber of
spec-
imens.

29/7 1896
4 p. m.

St. 125

68°o8

l6°02

Apst. 68

2-1° C.

25 %

74 °/o

I o/o

224

■o/, 1896
4-30 p. m.

St. loi

66°23

1 2 =05

V 100 — 0

5-5° C.

14

16

I

7

5

■•

20/5 1S96
i2t'5 a. m.

St. 59

65=00

ii°i6

P. 100— 0

1-6° C.

87 °/o

12 0/0

I °/o

91

11.15 p. m.

Apst. 12

1-5= C.

24

21

••

24/7 1896
3.30 p. m.

St. 117

68=13

8=03

V2 100— 0

4-1° C.

14 %

13.5 °;o

36 0/0

35 %

1-5 =/o

150

Thor

22/7 1904

St. 214

67°i9

17=55

Yt. 800 M.W.

20 0/0

27 0/0

53 %

•■

75

Norwegian Sea etc. In the western part of the Norwegian Sea between 60° L. N. 3° L. E.
and 69° E. N. 6° L. W. the Danish East Greenland Expedition has not in any of the 84 surface
samples (F 1—89), which were collected from '9-24/5 and contained plenty of C. finmarchicus, found
C. hyperboreus. With E. 14 a single f? was taken "je c. 64° L. N. 0-51 E. W. The same expedition
has near Jan Mayen with a closing net made several vertical hauls, and a few horizontal ones with a
big net, which makes it evident that the species was ratlier common in this region.

The Ingolf-Expedition. III. 4. c

34

COPEPODA

Of 5 samples from Jan Mayeii (^J 6 i a. m. — 5 a. m.) 4 contained f$ (21 specimens), 5 (V) (34
specimens) and 3 stage (IV) (6 specimens only); of 8 day samples 5 (taken 6 a. m. to 11 p. m.) did
not contain any specimens, but 3 (12 a. m. — 3 p. m.) contained together 9 f$.

Date.

0. Exp. 1900
at Jan Ma3'en.

VI

V

IV

III

II

I

Number of
specimens
examined.

23/6 12-30 night

Horizontal net.

At the Surface

87%

13 %

,

100

»5/6

Closing net.

50 — 60 fathoms

10

17

I

»8/6

?

20

2

3

4

8

V; I p. ni.

Closing net.

25 —10

50 —25
100-50

10 0/0

I
I

400/0
3
4

21 %

29 0/0

60

From the ^^/e 10 p. m.— V7 1900 the East Greenland Exp. has near Jan Mayen collected c. 40
samples (F. 90 — 135); 27 day samples (6 a. m. — 7 p. m.) were taken, of which only F. 125 (V7 1912
mid-day 7i°3i N. 7°43 L. W.) contained a single f$; of 13 night samples the 4 following contained
C. //., and the f$ most abundantly.

Number of

0.Exp. 1900.

VI

V

IV

specimens
examined.

28/6 10 p. Ul.

Jan

Mayen

F. 90

85 °'o

15 %

106

1 1 p. m.

1 " ^'

5

4

I

12 p. m.

- 92

40

4

29,6 I a. m.

- 93

3

15

6

In the ocean tract crossed by the East Greenland Expedition from ^ „ i a. m. to y/^ 12 p. m.
between 73° L. N. 4° L. W. and 74° L,. N. 11° L. W. 109 samples (F. 136—244) were taken, partly
along the ice-edge or among scattered ice. As is easily seen in the following table the adult females
are the most frequent; the species is rather scarce at the surface and there is not seen to be any
marked difference in its occurrence in different times of the dav.

0. Exp. 1900 2-9/7.

Number of

samples

without

C. h.

Number of

samples

containing

C. h.

Number of
f9.

Number of
stage V.

Number of samples and (53. ni.
specimens taken I 8 p. m.

-7 p. m.
— 4 a. m.

Summa

43
40

16
10

54
12

6
6

83

26

66

12

That the species was well represented in the greater depth even at localities in which it was
scarce at the surface is shown by a few vertical hauls (cf. table p. 35).

COPEPODA

35

By Dei dim a nil 3 f? f 5 (V) were taken as far north as 75°37 L. N. and 6°40 L. W. As the
Danish East Greenland Expedition from the coastal waters only took the species in tlie few above
mentioned samples, and as not one was fonnd in 13 surface samples (F. 244 — 262) taken from 9/^ — '7/7 in the

Date.

L.N.

L. W.

0. Exp.
1900.

VI

V

IV

Number
of spec-
imens.

4/7 3 P- m-

73°32

3°30

300— om.

83%

160/0

I°/o

114

8/7 2 p. m.

74°09

ii°3i

400 -om.

23

I

3

■0/7 6 a. m.

74°28

i5°36

no— om.

7

15

I

'^/7

72°02

2I°20

35-10

2

I

sea north-west and west of Jan Mayen, and as not one was collected in 47 samples (F. 265 — 310) taken
on the voyage home from 3%— Vg between Forblasfjord and 67° L. N. 23° L. W., there is reason to suggest
that the species was not very common in the mentioned period.

Distribution. This species has its main area of distribution in the North-Polar Basin, (but has at
the present only been found as far east as 136 h. E.), where its propagation probably takes place; it is
found at the surface as well as in the lower layers. In the waters, which connect the polar seas, it is equally
found viz. the Bering Strait (von Bremen), the Barents Sea, the Davis Strait (Ingolf Expedition,
Vanhoffen and Stephensen in Karajakfjord), but especially in the ocean between Spitsbergen and
the east coast of Greenland. It was here found from the surface or 5—10 met. below it, when there
was floating ice, down to about 1000 meters. Probably carried by the north polar current it was found
in the North Sea, but generally in small numbers and in the lower layers. The area around Iceland
in which it occurs in abundance "coincides almost exactly with the path of the east polar current
and takes the form of a broad tongue passing in a south-easterly direction between Iceland and Jan
Mayen and reaching almost as far as the Faeroes" (Farran p. 89). By the south-going bottom current
it is probably carried over the Wyville Thomson's and the Iceland-Fseroe ridges, and is accordingly
found scantily in the deeper layers of the North Atlantic as far south as 54° L. N. on the west coast
of Ireland. By the assistance of the Labrador- and the Kuro-Sivo currents the species is probably in a
similar way distributed over the West-Atlantic and the Pacific. In the Skager Rak and the deep fjords at
the west coast of Norway it is sometimes found abundantly, according to Sars, as a relict fauna. If
he is right, it should be pos.sible to find it in propagation here. It should be interesting to know, if
the species in the deep Atlantic is sometimes propagating, or if the stock must be renewed. The
temperature under which this species is found abundantly, lies between -^ i-g and -j- 6'0, the salinity
between 33-15 °/oo and 3518 °/oo. About the details in the biology and distribution of this species I refer
to the papers of Farran and Damas-Koef oed.

Remarks. This species is in the three last stages easily distinguished from Cal. Jinmarchicus.
But the distinction in the earlier stages, in which the difference is only found in the size etc., may,
as pointed out by Dam as & Koefoed, be very difficult if not impossible, especially in the polar sea,
where Cal. Jimnarchicus attains a size of 5 mm. or more.

5*

,6 COPEPODA

Macrocalanus G. O. Sars.

1883. Calanus pars Brady. I 1907. Megacalanus G. (). Sars.

1905. Macrocalanus G. O. Sars. 190S. Megacalanus Farran.

1906. Megacalanus Pearson. 1 1909 Bradycalanus Scott p. 14.

1906. Heterocalauus Wolfendeu. ; 191 1. Heterocalanus Wolfenden p. 201.

^iJ*^^ Since Wolfenden, as the first, established a new genus, Alagacalanus^ for a big Calanoid from

'^ the deep Atlantic, four other genera viz. Macrocalamis G. O. Sars, Flctcrocalamis Wolfenden, Bathy-

calanus G. O. Sars, and Bradycalanus Scott, more or less related to the original one, have been
established. A good deal of confusion about the right definition of these genera has risen. Scott
and Wolf enden have both tried, but only with partial success, to find the right names for the most
natural groups of species.

About the genus Ba/hycalainis G. O. Sars not much discussion in necessary. By Sars it was
characterized by the ribbon-shaped and densely-ciliated bristles on the lobes of the maxillae and
maxillipeds, and by the two-segmented Re of pes I; the described species [B. Richardi) has 2 distinct
spines covering the rostral filaments and "assez greles" rostral processes. As Wolfenden has examined
a specimen of B. Richardi G. O. Sars with indication of segmentation between Re II and III pes I,
and as his other species B. niaxinms Wolf, has a three segmented Re pes I (without Se as in the
other species) and with long and stiff rostral processes, he regards the structure of the maxillae ^
maxillipeds and the frontal teeth as the most important character (p. 198). Scott (1909 p. n) is certainly
wrong in not accepting Bathycalanus maximus Wolf, as belonging to Sars' genus on account of the
differences in the segmentation of Re pes I.

Wolfenden writes (1911 p. 201) "Ob die Charaktere dieser drei Gattungen geniigen, um ihre
Abtrennung von einander zu rechtfertigen, kan Ansichtssache sein; wenn aber die generische Unter-
scheidung von Bathycalanus und Megacalanus anerkannt wird, so erscheiut audi die Abtrennung von
Heterocalanus als eigene Gattung berechtigt, denn Heterocalanus unterscheidet sicli von jeder der
beiden andern Gattungen deutlich durch die Bewaffung der Maxillipeden, die Form des Kopfes und
den Bail des 5 Fusspaares". From this point of view Wolfenden as well as Scot t (1903 p. 11) are right,
and Sars wrong in referring his Macrocal. princeps and longicornis to the same genus, but his
Bathycalanus Richardi to a new genus. The go^nns Megacalattus Wolf, with M. princeps'^ o\i. as the
type is characterized by the hook on the anterior surface of the Ba.sp. Ill pes I and the slender bristles
of the maxillae. Wolfenden, who rightly recognised that Brady's Calanus princeps is nearly
related if not identical with his Heterocalanus medius^ ought in every case in his later publications to have
accepted Sars name Macrocalanus, which according to the general rules of nomenclatures had priority,
especially as Afac. princeps Brady is naturally regarded as the type of the genus and as the name
Heterocalanus has been previously used for anothed genus of Calanoids. In the Report from the
Siboga Expedition, Scott (p. 44) established a new genus Bradycalanus with a single species B. fypictis,
which differs from Heterocalanus by the head withovit crest, by the pointed lateral corners of the
last thoracic somite, and by the well developed Se of Re I— II pes I and 2 Se Re III of pes I. He
writes: "I think that it is probable that Brady's Calanus princeps belongs to this genus rather than
to Bathycalanus or Heterocalanus'''-, accordingly, instead of establishing a new generic name, he ought
to have accepted Macrocalanus G. O. Sars.

COPEPODA 37

Scott suggest that Hcterocalanus vicdms Wolf, is identical with Kroyers Calamts cristatus\
this species, of which I have examined the type specimens, is however a true Calanus (of. p. ii).
On account of the existing confusion I think the following synoptic key will be useful.

I. Strong hook on anterior surface of hasp. Ill pes. i; pes I — IV with 3 segmented Re and Ri. The
maxillae without densely plumous setae in distal lobes Alcgacalanus 2.

1. Strong hook on anterior surface of hasp. Ill pes I wanting 3.

2. 3 Se of Re III of pes II — IV Megacalatms priiiccps Wolf.

2. 2 Se of Re III of pes II — IV Calanus gracilis Dana.

Calanus rohnstior Giesb.

3. Maxillae without densely plumous setae. 2 vSe of Re III of pes II — IV Calanus

3. Maxillae with densely plumous setae. 3 Se of Re III of pes II — IV 4.

4. Maxillipeds with slender setae Macrocalanus. 5.

4. Maxillipeds with densely plumous setae. Re pes I without Se. Front with 2 conical processes

Bathycalanus G. O. Sars. 6.

5. Frontal crest. Rounded lateral corner. Pes I has no Se in Re I — II, one Se in Re III

Macrocalanus (Hcterocalanus) priiiccps Brady.

5. Frontal crest wanting. Pointed lateral cornes. Pes I has i Se in Re I— II, 2 Se in Re III

Macrocalanus (Brady calanus) typiciis Scott.

6. Re pes I two segmented. Rostral processes rather slender Bathycalanus Richardi G. O.Ssirs.
6. Re pes I with 3 segments. Rostral processes long stiff rounded Bathycalanus maxitnus W o\i.

3. Macrocalanus princeps Brady.
(PL I figs. 2a — b; textfigs. 7 a — b).

1S83. Calanus princeps n. sp. Brad}', pp. 36—37, pi. IV 1906 ? Hcterocalanus medius n. sp. Wolfenden pp. 27— 28.

figs. 3—7. pi. VIII figs. 1-5.

1904 nee. Megacalanus princeps n.sp. Wolfenden pp. 112 — 113.

1905. Macrocalanus princeps Brady. G. O. Sars p. 7.

1905 nee. Megacalanus princeps Brady. Wolfenden pp. 3—5

pi. I figs. 7—9.

1906. Megacalanus princeps Brady. Pearson p. 5.

1908. Megacalanus princeps Brady. Farran p. 21.

1911 nee. Megacalanus princeps Wolf. Wolfenden pp. 196 — 19S.
1911 ? Heterocalanus medius Wolf. Wolfenden pp. 201 — 202

taf. XL figs. 1-5.

Description f$. Size. Anterior division 5-5 + 5 mm; posterior 3 mm; total length 13-5 mm. The
body is slender, as the anterior division is about 2-5 as long as wide. The first as well as the fifth somite,
the lateral corner of which is regularly rounded (fig. 7 b), are well distinguished. The head has a low
crest terminated by a small frontal process. The rostrum consists of two powerful rounded spines,
parallel and directed downwards. At the base slender rostal filaments protected above by low pro-
cesses. The hinder margin of the head has dorsally a small elevation bearing a conical process. The
urosome consists of four somites, of which the first — the genital one — , ventrally produced in front,
dorsally behind, is distinctly wider and deeper than long, and distinctly twice as long as the following
somites. The furcal rami are a little shorter than the third somite and 1-2 as long as wide.

The antennulae project at least 6 segments beyond the tip of the furca; they consist of 25
segments, of which, however, the 8 and 9 are less well separated. The segments increase in length

38

COPEPODA

from the 8 to the 17 segments, but decrease from the 20 to the 24, which is scarcely half as long as
the 23, which is of almost equal length to the 25. In the basal segment ouly 2 terminal setae are
observed; the second segment bears three tritheks, and the following 17 segments bear a single one,
consisting of rather delicate setae; the 20—23 segments have only 2 terminal setae (Sd + "^sthe-
taskeu"), the 24 segment has a single long and slender seta and the 25 segment has 6. Segment 22
has a delicate posterior seta (Sp.) and the two last segments each bear a powerful, ringed plumous
one, at least twice as long as the two segments combined.

Antennae are in the main alike Calamis, but the Si of the Basipodite II is very short and
the Re I and II have no Si, but the latter segment has two processes medially.

Mandibulae: The manducatory part is rather short with the first to the fifth serrations well
developed without accessory teeth; the sixth to the eighth serrations are only poorly developed. The

four partly plumous setae, of about equal length, are shorter than the width of
the segment. The Ri I has ouly 2 setae and the Ri II has 8 setae anteriorly
and a single one posteriorly.

Maxillulae: The Le I has the 2 first setae extremely short, almost
rudimentary, and the following 7 long and plumous; the Le II is only indistinct
without any seta. The Li II, which does not bear any seta, is comparatively
shorter than Li III, which is fairly slender with 2 setae only. The Basp. II has
2 moderately slender setae (Sp. ?); the Ri I — II which are indistinctly separated
from each other as well as from the basipodite, have a single seta each, while
the well distinguished Ri III bears 4 long and one single rather short seta. Re,
which has the usual eleven plumous setae, extends a little beyond the end of
the endopodite.

Maxillae are in most respects alike Calaiitis, but the Lob. V bears
anteriorly 2 long slender ribbon-shaped setae, and the Ri, which has the articular membranes rather
indistinct bears six setae of the described structure.

Maxillipes: The proportions of Basp. I cs. II, Basp. Ill and Ri = 55:50:30; they are in the
main alike Calanus, but Ri II — IV have only a single seta each, and Ri V has 2 Si -(- i Se.

Legs are comparatively short and broad and have three segments in exopodites as well as
in endopodites. In the first pair the Re I — II has no Se and the Re III has only a single one, placed
a little nearer to base than tip. The Re I — III has i + i + 5 Si (cf. Wolfe nden t XI fig. 5, in which,
however, the Se Re III is placed distinctly nearer tip than base). The second pair of legs has the
Ri extending just beyond the end of Re II; the Re I — II is i-i shorter than Re III, but i'6 as long
as the distinctly serrated St.; the Re I— II have each a Se and the Re III has 3. The third and
fourth pair of legs are in the main features alike the second pair. The fifth pair of legs is smaller
than the others and differs in several respects. The inner margin of the basipodite II and III are
almost straight, thus differing distinctly from pes. II, and in a less degree from pes. Ill — IV. The Ri
extends beyond the base of Re III to the insertion of Se 2. The Re I— II have each one Se and the
Re III has 2; the number of Si is 4 in Re III and i in Re II, but the Si is wanting in Re I.

Secretory pores are in pes II found on the the anterior surfage at the base of Se Re II

Textfig. 7.

Macrocalamts princt'ps

Brady, a. Head of adult

male. X S'5. b. Abdomen.

X8-5.

COPEPODA

39

and the Se I — III of Re III, and, surrounded by a number of fine hairs, somewhat removed from tip,
on the anterior surface of Ri III; in addition to these the pes III— V have a pore at the base of Se
Re I, and so has pes V, in which, however, only 2 pores are observed in Re III.

The number as well as the arrangement of the "maculae cribrosae", of which none was
observed in the mouth-appendages, is less regular than in Mcgacalamis. On the anterior surface of
Re I, at base of Se, the organ was observed in pes II— III, but not in pes IV. On the posterior surface
the maculae were sometimes found near the base of Se Re I pes II, and regularly in pes II as well as
pes III near the base of Se Re II and Se I — II Re III; in pes IV only a single group was observed
in Re II.

On the anterior surface of pes II — III, medially to insertion of the Re, a group of delicate fila-
ments, projecting through minute pores (?) and perhaps corresponding to a macula cribrosa, was found.

The lateral outline shows, somewhat in front of the lab rum, a low rather elongated elevation.
In the middle, as well as on each side, well removed from the hinder margin, a group of fairh- long
and slender, delicate hairs are observed. The posterior margin has a median incision, and well removed
from the middle on each side a transverse marginal row consisting of about 15 short lancet-shaped
spines (fig. 2 a). On the oral surface the usual longitudinal series is dissolved into 5 more or less trans-
versely placed groups, as shown in fig. 2 a pi. I; the bristles of the more posterior groups are more
slender and longer than those of the anterior ones; between the group (Nr. 4) on each side and behind
the fourth central spot a transverse row of granules is found.

The lamina labialis has i median and on each side 2 lateral teeth; in front of this we
have an exterior and mostly anteriorly slightly convex series of rather long bristles and an interior short
one of shorter bristles (pi. I fig. 2b). The serrula 6-dentata has the 4 posterior spines club-haped;
between these and the labial lobes scarcely any setae were observed. The area labialis has behind the
labial lobe a median somewhat convex group, and a lateral oblique group of numerous hairs on each
side; the labial lobes bear about 8 groups of shorter and longer hairs, which seem to be arranged in
3 series.

Y (St. V). Size : 8-4 -j- 2-2 = io-6 mm. The shape of body is scarcely different from that of the
f$ except for the urosome, which has four somites, hardly produced beneath, of which the second
is almost twice as long as the first, which is the shortest The antennulae extend only 4 segments
beyond the end of the furca; the measurements differ in minor points only; the maxillulae have in
one specimen only a single seta in the hasp. Ill in another 2 as in f$. The Re has only 10 setae.
In other respects no difference was observed.

Y (St. III). Size 6-1— 6-3 mm. (no + 0-53).

Of this stage I have examined 2 specimens; in spite of the different shape of the head and
the short antennulae I do not doubt that the animals are rightly referred to this species, as they agree
with it in several important features e. g. the curious structure of the maxillulae.

The body in much more slender, and the head shows no trace of a frontal keel ; the first as well
as the fifth thoracic tergite is well marked. The urosome consists of 2 somites, of which the second
is almost twice as long as the rostrum as well as the furcal branch. The antennulae, which just
reach beyond the end of the abdomen with the tip of the last segment, consist of 23 segments; the

.Q COPEPODA

25 is 2'i as long as the 24 and I'l as long as the 23. The Le as well as the Re of the niaxillulae
have only 11 setae. The distal setae of the maxillae show indication of the curious structure found
in the full-grown. The pes I — III have the Ri II csj III and the Re II c«o m fused; the Re II <v) III pes
II has 3 Se and 5 Si; the Re II o-- III pes III has only 2 Se; and its Ri has 8 setae. The pes IV
has Ri IojIII fused with 7 setae and the Re I 00 HI has 3 Se and 3 Si. The fifth pair of legs is, as
shown in Ca/. Jinmarchicus, quite rudimentary. In contrast to the full-grown female a distinct pore
was found at the base of Se hasp. Ill of the pes II — III; in addition to this a pore was found at the
base of Se Re I and Se 3 Re III.

Occurrence. This species has not been captured by the Ingolf Expedition, but the Thor
Expedition has taken it from the following stations 1904 and 1905.

Thor '9/6 1904 St. 152 65°oo Lat. N. 28°oi Long. W. Yt. 1000 M. Wire 2 f?.

'% 1905 St. 180 6i°34 Lat. N. i9°05 Long. W. Yt. 1800 M. Wire 3 f ?.

"/y 1904 St 183 6i°30 Lat. N. i7°o8 Long. W. Yt. 1800 M. Wire 4 f?; 2y (V); 2 (III).

25/5 1904 St. 104 62°47 Lat. N. i5°o3 Long. W. Yt. 1500 M. Wire i f?.

"/5 1904 St. 99 6i°i5 Lat. N. 9^35 Long. W. Yt. 1700 M. Wire i f?.

7/6 1905 St 71 57°47 Lat N. ii°33 Long. W. Yt 1500 M. Wire 2 f?.

8/6 1905 St 72 57°52 Lat N. 9°53 Long. W. Yt 1500 M. Wire 2 f?.

"/g 1905 St 167 57°46 Lat N. 9°55 Long. W. Yt. 1500 M. Wire 3 f$.

Distribution. This species has previously onl)- been recorded from the great depths in the
Atlantic Ocean viz. from the west coast of Ireland as far north as 55° Lat North, from the North
Atlantic (c. 40° Lat N. 70° Long. W.) and the Mid Atlantic (c. 10° Lat N. and 20° Long. W.). As it
has not been taken by the Siboga Exp., it is rather doubtful if it is found in the Indian Ocean.

Remarks. It seems to me scarcely doubtful, that the described species is identical with Brady's
Calanus princeps; this author writes: The abdomen is short, stout and three-jointed. The latter character
is certainly due to a mistake. His fig. 5 of the maxillula shows, probably wrongly, only 6 setae in Le
I and 10 in Re. As I have examined specimens, identified by Sars, it is scarcely doubtful that the
species is identical with Sars and Farran's Megacalanus princeps Brad)-. Farran has suggested, that
Wolfenden's Hcterocalanus medius is identical with Cal. princeps Brady, and I think he is right My
specimens differ from Wolfenden's fairly exhaustive description (1906 p. 27) in the following features:
i) Le I niaxillulae has 9 instead of 7 bristles and the 2 setae of basp. II are not "very short and
delicate". 2) the Se Re III pes I is placed nearer the base than the tip.

Megacalanus Wolf end en.

1904. Megacalanus, Wolfenden 1908. Megacalanus pars, Farran. p. 21.

1905. Macrocalanus pars, G. O. Sars. 1909. Megacalanus, Scott, pp. 10 — 12.

1905. Megacalanus pars, Wolfenden. 1 191 1. Megacalanus, Wolfenden, pp. 195—196.

1906. Megacalanus pars, Pearson, p. 6. j

The type of this genus, which is probably more related to Calanus than Macrocalamis and
BathycaUnnis. is M. princeps \ it is well characterized b}- its size and the curious hook on the anterior

COPEPODA

41

surface of tlie third basipodite of the first pair of legs. Scott has proposed to refer Calanus gracilis
Dana and Calanus robiistior Giesbrecht to the same genus, in spite of smaller size, on account of
a similar hook. Possibly he is right; but as I have not had the opportunity of examining any spec-
imens of the two said species, I do not feel competent to judge in the case.

3. Megacalanus princeps Wolfenden.
(PI. I figs. 3a-i; textfigs. 8 a— d).

1904. Megacalanus princeps n. sp. Wolfenden, pp. 112 — 113.

1905. Macrocalanus longicornis n. sp. G. O. Sars, p. 7.
1905. Megacalanus bradyi n. nom. Wolfenden, pp. 1—3, pi. I,

figs. I — 6.
1905. Nee. Megacalanus princeps Brady. Wolfenden, pp. 3—4,

pi. I, figs. 7-9.

1906. Megacalanus longicornis G. O. Sars. Pearson, p. 5.
190S. Megacalanus longicornis G. O. Sars. Farran, p. 21.
1909. Megacalanus princeps Wolfenden. Scott, pp. 13 — 14,

pi. I, figs. 12 — iS.
19H. Megacalanus princeps Wolfenden. Wolfenden, pp. 196

— 198, taf. XXIL figs. I -II.

Text-figure 8.
Megacalanus princeps Wolfenden.
a. Head of adult female X 16. b. Abdomen of adult female >
d. .\bdomen of young female (stage V)

1 5. c. Pes I in situ X 67.
16.

Description f$. Size: 10-5 mm. (anterior division 8-5; urosome 2). The head is slightly produced
between the base of the antennulae and is without any crest. The rostral filaments are short and placed
on a low elevation just above the rostrum, composed of a short basal part and two slightly convergent
rather obtuse, fairly long spines, directed backwards and downwards. The five thoracic somites are well
distinguished; the fifth is laterally triangularly produced. Projecting from the hinder margin of the
head a small process, similar to that of Macrocalanus, though less prominent, is observed.

The abdomen is only one fourth of the anterior division in length. The genital somite is as
long as deep and wide, and in front ventrally produced.

The antennulae^ which are at least 8 segments longer than the body, have all 25 segments
well separated, except the VIII and IX, with the articular membranes wanting posteriorly. The
segments increase in length from the 8 to the 17; beyond the 19 they are much shorter; the 23 is 1-4
as long as the 25, which is only i-i as long as the penultimate one. The 13 and 14 have in the distal
part, ventrally and exteriorly, a row of delicate teeth (according to Wolfenden they are found in seg-
ment 12 and 13). The bristles of the antennulae are rather delicate; the posterior setae of segment
23 — 24 are rather weak, and scarcely 1-5 as long as two distal segments (in Scott's figure they are

Tlie Ingolf-Expcdition. III. 4. 6

42 COPEPODA

distinctly twice as long). The arrangement and number pi setae are alike that of Macrocalaims^ and
agree with Calamis by the presence of a single seta instead of two in segment 21.

Antennae are in the main alike those of Cff/f?;/?/^ (cf. Wolf enden), but the Re II is by an
incomplete articular line divided into a proximal division, bearing two setae, and a shorter terminal one
with a single bristle.

Mandibulae (figs. 3 a and c) of. Wolfenden (taf. XXII fig. 5) have a well developed manducatory
portion with five distinct teeth and a few more or less fused.

Maxillulae are alike Calannsfimnarchicus in most features, but differ by comparatively long
Re, and by the presence of 3 setae instead of 4 in Ri I (as seen in Wolfenden's fig. 2).

The Maxillae (fig. 3d) and Maxillipeds are as described by Wolfenden (taf. XXII figs. 4
and 6) in the main features alike those of Calamis, but the former organ has the fifth lobe comparatively
long with a thin hook, and the latter has the hairs, which cover the anterior surface of the Basp. Ill
proximally and medially bifurcate or divided into three branches, and the Se of Ri 4 — 5 are compara-
tively short and unarmed.

The five pair of natatory legs have three segments in exopodites and endopodites; in basipod
III pes I a characteristic structure is found in the upwards directed hook, which dorsally in the concavity
has a rather irregular process, and ventrally bears the slightly plumous Si; this hook is indicated in
most species of Calanus and in Macrocalatms as a small process on which the Si is placed (cf. Giesbrech t
p. no). Pes II has the inner margin of second basipodite almost straight (cf. fig. 3 e). Thes pes III — IV
is in main features alike pes II, but Ri II with distinct Se. The pes V (fig. 3 h) is in general structure
like the preceding pairs, but is distinctly shorter; the inner margin of basp. has no hairs and no Si.

Glandular pores, surrounded b\- prominent rings are observed in the pes II— IV, as shown in
fig. 3 e at the base of Se basp. Ill and Re I — III, and are observed surrounded by fine hairs distally
on the anterior surface of Ri III; the last mentioned pore and the pore corresponding to the wanting
Se I Re III are absent in pes V.

Maculae cribrosae: In the legs and in a less degree in the other appendages small spots,
consisting of a more or less circular ring of minute pores, continued into a delicate threadlike glandular
duct? (fig. 3 f — g), are observed.

As the arrangement of these, "maculae cribrosae" seems to be fairly regular, and as I have
only observed them in Mcgacalanus and Macrocalatms^ I think they are of some systematic importance
and hope that the following account of their number is fairly exhaustive; they are often rather diffi-
cult to observe. The antennulae possess on the upper surface of the second segment a group of 9
pores; on the anterior surface of the Ri I of the antennae, at the base of the distal third, a group
of about 15 pores is observed. The manducatory part of the mandibulae bears at the base of the
serrations at least a single group, and the basp. Ill at least 2 rings of 7 pores anteriorly. The maxillulae
bear on the anterior surface a group of 14 pores at the base of Le I and basally near the lateral
margin of Re. In the maxillae a single group of 12 pores is observed on the anterior surface of the
first basipodite and near the outer margin.

On the posterior surface of the first pair of legs no pores are found; anteriorly a group of 10
pores is observed in basip. Ill medially to the articular cavity of Re I, and another one is seen in the

COPEPODA 43

middle of Ri II. lu the second pair of legs, on the anterior surface, pores are found near the lateral
margin of basip. II (on the left side a single group of lo pores and on the right side two groups of 6 pores),
in the basip. Ill medially to the insertion of Re I and in Re I near base of the process bearing Se; on
the posterior surface of basip. II, and at base of Se Re II and Se i — 2 Re III, a rather indistinct group of
pores is found. In the third and fourth pair of legs, groups of pores are also found posteriorly at base
of Se hasp. II and Re I ; in the fifth pair of legs only a single group was found in Re III posteriorly
(at base of Se I).

As the number and arrangement of the maculae cribrosae in the mature male are scarcely dif-
ferent from those in the female, and as only the groups in the maxillulae, but not those in the nata-
tory legs, were observed in the Copepodites (stage IV— V) it seems to be possible, that the main-
purpose of the maculae cribrosae is connected with the sexual life (e. g. light organs).

In front of the labrum and well distinguished from it, a fairly prominent elevation is found.
The labrum itself is rather elongated (PI. I, figs. 3 a — b and text-fig. 8 a). Anteriorly a transverse row
of delicate hairs is found, and posteriorly on each side of the median incision a transverse marginal row
of about 25 rather short lancet-shaped spines in addition to two somewhat convex rows, and a small group
of delicate hairs. The oral surface of the labrum has in front two well separated oblique groups. The
three following groups are placed more longitudinally as seen in fig. 3 b. Only corresponding to the
fourth central spot a few hairs are seen in a transverse row. The lamina labialis is, as seen in fig. 3 c,
fairly distinct without serrations ; in front of this an outer convex series consisting of fairly long hairs,
in continuation of the serrula 6-deutata, and three inner series of very delicate hairs are observed.
Behind the lamina labialis, between and upon the labial lobes and behind these a number of series and
rows of delicate hairs are found ; about their arrangement I refer to fig. 3 a.

fc?. Size: 106 mm. (anterior division 8-5; urosome 2'i). The body is more slender and the process
of the posterior margin of the head is better developed. The abdomen consists of 5 somites, of which
the second is 2'5 as long as the first and 1-2 as long as the third.

The antennulae (PI. I fig. 3 i) have the articular membranes between the 7—9 segments less
well developed than between the preceding and following ones. The number of the bristles shows a
similar difference from that of the female as in Calanus. The "^-Ustetasken" are powerfully developed and
the Sd of segment 9 is represented by a clavate structure (fig. 3!). The other appendages do not show
any difference from those of the females except the fifth pair of legs. In these the hasp, and Ri are
scarcely different, but the Re have no Si except the Re II of the pes V sin, which has the Si (?)
represented by a stumpy articulated process, prolonged into a somewhat twisted feathery spine, at the
base of which long and stiff hairs are seen; marginally a dense seam of hairs, as figured by Wolf en den
(fig. 9), is seen.

Y. (V). Size: 8-2 mm. (anterior division 6-5, urosome 17). The shape of body is in main as in f$,

but the lateral corner is more pointed and the urosome consists as seen in fig. 8 d of four somites, of

which the first one is prominent ventrally. The mouth appendages seem in the main features alike

those of mature females; the Re of the maxillulae possess as usually 10 for 11 setae. The second

pair of legs differs by comparatively short Ri, which does not extend to the end of Re II, and by

the wanting glandular pore at the base of Se I Re III; the same pore is wanting in the fourth pair

6*

44

COPEPODA

of legs and the corresponding Se is distinctly smaller than the following. The fifth pair of legs
has the Ri II— III fused with the usual number of setae, as well as the Re II— III, bearing 3 Se (pore
at base of Se I missingl and 5 Si.

Y. (IV). Size: 6-8 mm. (anterior portion 5-5; posterior 1-3). The body differs distinctly by a three-
segmented abdomen; the first somite, which is slightly produced beneath, is the shortest, and i-6 shorter
than the third one. The antcnnulae, especially the distal segments, are comparatively longer; the
number of setae differ in several details. The vtaxillnlae differ by a smaller number of bristles in
Ri (Ri I has f. inst. only 2 setae) and by 9 setae of Re. The first pair of legs have the Ri II —III
fused with 8 setae, and the Re II — III with 3 rather slender Se, but only 4 Si. The second pair of
legs has the Ri II — III fused with 9 setae, and the Re II — III fused with 3 Se and 5 Si; glandular
pores as in preceding stage. The fourth pair of legs has 7 setae in Ri II ess III, and 5 Si and 3 Se,
of which first one without glandular pore, in Re II ^ III. The fifth pair of legs has the Ri I ^ III
with 6 setae and the Re Ic^^III with 3 Si, 3 Se and a St.; only a .single pore at base of Se III
is found.

Occurrence. This species has not been captured by the lugolf Expedition, but has been taken
at the following stations in deep hauls by the Thor 1904 — 1905 south and west of Iceland.

Thor '9/6 1904 St. 152 65°oo Lat. N. 28°oo Long. W. ly (IV).

■3/7 1903 St. 164 62°io Lat N. i9°36 Long. W. if?.

■% 1904 St. 180 6i°34 LaL N. t9°o5 Long. W. Yt 1800 M. W. 2 f?; 3 fc?; ly (V).

"/; 1904 St. 183 6i°30 Lat N. i7°o8 Long. W. Yt. 1800 M. W. 4 f?; 4 fj*; 5y (V); i y (IV).

24/5 1904 St. 104 62°47 LaL N. i5°03 Long. W. Yt 1500 M. W. ly? (V).
■^5 1904 St 78 6i°o8 Lat N. 9°28 Long. W. if?.

*9/8 1905 St 167 6o°oo Lat N. io°35 Long. W. Yt 1000 M. W. i f?.

31/8 1905 St 167 57°46 Lat N. 9=55 Long. W. Yt 1500 M. W. i f?; i y (V); i y (IV).

8/6 1905 St 72 57°52 Lat N. 9°53 Long. W. Yt 1500 M. W. i f?; i y (IV).

23/7 1905 St 124 6i°04 Lat N. 4=33 Long. W. Yt. 1000 M. W. if?.

Distribution. This species seems to be fairly common in the Fseroe-Shetland Channel, and on
the west coast of Ireland between 600 and 1000 fathoms. It has been taken in the Atlantic by the
Gauss Expedition as well as at a single station in the south polar region (c. 65° Lat S. c. 85° Long. E).
By the Siboga Expedition it has been taken at three stations at about 4° Lat S. 129 Long. E.

Eucalanidae.

Rhincalanus nasutus Giesbr.
(PI. I figs. 4a— e).

1877, Rhincalanus gigas Brady. Mobius.
18SS. — nasutus n. sp. Giesbrecht, p. 534.

18S8. — gigas Brady. J. C. Thompson, p. 14S.

[892. — nasutus Giesbr. Giesbrecht, pp. 152 — 158,

taf. 3, 12 and 35.

1898. Rhincalanus nasutus Giesbr. Giesbrecht & Schnieil pp.

22-23.
1901. — gigas Brady Th. Scott, p. 237; pi. XXVII

figs. 1—4.

COPEPODA 45

1902. Rhiucalanus gigas Brady. Th. Scott, p. 450.
1902. — nasutus Giesbr. G. O. Sars, pp. 15 — 16 pis.

VJ-VII.

1903
1903
1903
1903
1904
1904

J. C. Thompson, p. 16.
Thompson & Scott, p. 242.
Norman p. 135.
Cleve, p. 36S.
Wolfeuden, p. 128.
Cleve, p. 196.

1905. Rhincalanus nasutus Giesbr. G. O. Sars, p. 2.

1905. — _ — Xh. Scott, p. 222.

1905. — - — Esterly, p. 137, fig. ic.
igo5. — — — Wolfeuden, p. 996.

1906. — — — Pearson, p. 8.
1908. — — — Farran, p. 22.

1908. — — — V. Bremen, p. iS fig. 14.

1909. — gigas Brady. Scott, pp. 24 — 25.

1910. — nasutus Giesbr. Farran pp. 18—19.

1905. — — — Farran, p. 30.

Description f$. The females examined varied in size from 4-5 to 5 mm. When this characteristic
species is examined in lateral view, a marked difference is observed between the different specimens in the
outHne of the head; in some animals a distinct pointed eminence is seen jnst in front of the insertion
of the antennulae, in others the outline in more even as figured by Sars; the size of this eminence
is probably dependent upon the preservation of the animal and the position of the antennulae in the
moment of death. The structure of the limbs is scarcely different from Giesbr echt's description.
In the exterior margin in the middle between Se I and II of the Re II -nj III in the first pair of legs
a small incision with a circular pore(?), through which a minute conical eminence projects, is seen
(glandular pore?). In the three last pair of legs I have not been able to find secretory pores with
certainty.

As seen in Sars' figure the labrum, which is widely removed from the insertion of the anten-
nulae, is saddle-shaped and by a median line divided into an anterior and a posterior division (fig. 4a).
On the oral surface of the labrum, on each side almost attaining the middle, a row of fairly
long stiff hairs are found in addition to six short stout setae, more alike granules, in the middle partly
fused with transverse groups, and two posterior groups of partly sickleshaped spines, between which
large group of stout teeth are found (cf. PI. I fig. 4e). The lamina labialis consists of a median and
two lateral divisions (fig. 4 c). In front of this we have laterally an inwards convex series of fairly
long bristles; the inner longitudinal row is posteriorly represented by row of rather short spines or
granules and anteriorly with irregular group of similar spines. Behind the lamina labialis and between
the serrula 6-dentata the setae are arranged as figured. The lobus labialis possesses 4 longitudinal
series or groups of hairs, which posteriorly and inwards are fused into a big irregular group of hairs,
extending between the two lobi.

fcf. Size: 3-8 to 4-5 mm. The head is less produced in front of the rostral filaments. The ab-
domen, which is one fourth of the length of the anterior division consists of five somites; the first one
is dorsally and posteriorly produced into a distinct spine, corresponding to that found in the genital
somite of the female. The two first segments of the antennulae are well separated. The antennae
(cf. PI. I fig. 4f) are more clumsy than those of the female, and so are the mandibulae, which have
a well developed manducatory lobe. The maxillulae, maxillae and maxillipeds, especially the
latter, which have the second basal segment scarcely twice instead of three times as long as wide, are
more clumsy than in the females, but scarcely less adapted for manducatory purposes. The mouth and
its surroundings are scarcely different from those of the female; the single specimen which I examined
had the spinulation of the labrum less coarse than in the female. The natatory legs are scarcely
different from those of the female. The internal sexual organs are found on the left side.

46

COPEPODA

Of this species Giesbrecht has only examined a single mutilated male from the Pacific Ocean.
The figure, which is represented on his pi. 9 fig. 14 is not quite like the structure found in several
males which I have examined, the main-differences being that the endopodite of the right leg in none
of my specimens is terminated with a short clumsy hair; it is rather doubtful if this difference has any
specific value, as the legs of the animals examined show marked variations in other respects. The
left leg consists of 2 basal segments and a fairly elongate exopodite (fig. 4g) produced into a more or
less curved terminal spine and a minute Se; only in a single one of my specimens, which had no Se, the
St was so strongly curved as figured by Giesbrecht (fig. 4h). In the four specimens examined the
exopodite of the right leg had a long St and a short slender Se; but the endopodite varied in a
curious way. In a specimen (fig. 4g) with the Ri about 5 times as long as wide, the articular line
between the last two segments was alSbst obsolete, and the posterior surface was more hairy than in
the specimen with the segment about 3-6 as long as wide (fig. 4h). In a single specimen (fig. 4J) the
Ri was represented by short segment, but this is probably due to a mutilation.

Y. $ — d* (St. V). Size: 3-5 — 4-1 mm. The "head" is about twice as long as the thorax, and the
anterior division is 5-5 as long as the abdomen, which consists of four somites; the last one is partly
fused with the furca; the first (genital) somite is produced beneath in the female, not in the male.
The appendages are in most respects alike those of the mature females; the only difference of any
interest is, that the exopodite of the maxillulae po.ssesses 8 instead of 9 bristles. While the fifth pair
of legs in the female is like that of the mature, this organ is in the male less developed than iu the
full-grown animal. The left leg (fig. 4k) is most similar to that of the female, but less slender; the Ri
is represented by a conical protuberance, and a minute Se is found in Re. The right leg possesses an
exopodite very similar to that of the left leg, and a fairly long and slender endopodite with a slender
terminal bristle. Brady gives (PI. VIII, fig. ro) in his description of Rh. gigas^ without having under-
stood its real nature, a figure of the fifth pair of legs in the young male; the Ri dext. has two bristles
in stead of a single one, and the Se of Re is missing; in the former feature a valuable character between
the yj* of the two species is probably found; the latter character is probably due to a mistake (or an
abnormity) as an exterior seta is present even iu the mature female of Brady's species (PI. VIII fig. 9)
as well as in Rh. graiidis Giesbr. in contrast to the female of Rh. nasutus.

Y. $ — $ (St. IV). Size : 3-9 mm. This stage is characterized by the three somites of the urosome.
The pes V is better developed in the male; the right and the left legs are as shown in fig. 4I nearly
symmetric. The Ri sin. is longer than in the preceding stage, but shorter than the Ri dext, which is
however shorter than the Re dext.

Variation. A mature female (Thor St. 72; fig. 4 b) had the lateral thoracic spine on right side
of fourth thoracic somite distinctly bifurcate (in the same specimen a nematode was dwelling as para-
site); a corresponding variation was found in a specimen from Thor St. 183, but in addition the right
dorsal spine of the first abdominal somite was bifurcate. In a mature female from Thor St. 82 the
latter abnormity was found on both sides and in a )oung female on the left side only. In a single
specimen (Thor St. 88) the Re of the right fifth foot has a lateral pointed projection (fig. 4d); about
the variations iu the fifth pair of legs in the males I refer to the description of the male.

COPEPODA 47

Parasitism. In several specimens the body cavity was partly filled with a nematod, which
was very distinct through the skin on account of its white colour; this parasite was observed in a young
female from Thor St. 153, in 5 i^ from St. 183 and in one from St. 82, and mag. sci. Hj. Ditlevsen
has kindly informed me that it is a larval stage, the exact determination of which is impossible on
account of bad conservation.

Occurrence. The Ingolf Expedition has collected this species at the following stations south
of Iceland.

•7/6 95 St. 18 6i°44 L. N. 30°29 L. W. V. 200—0 fm. Temp, at the surface 10° C. 3 $.

18/5 96 St. 54 63°o8 L. N. i5°40 L. W. V. 100— o fm. Temp, at the surface 9° C. 6 ?.

'3/5 96 St. 49 62°07 L. N. i5°o7 L. W. V'.ioo— o fm. 'Benxp. at the surface 9-3° C. 4?.

•2/5 96 St. 47 6i°32 L. N. i3°4oL. W. V. 100— o fm. Temp, at the surface 10" C. i y? (V).

'5/5 96 St. 52 63°57 L. N. i3°32 L. W. V. 200-0 fm. Temp, at the surface 8-3° C. 2 f ?.

^°/5 96 St. 57 63^37 L. N. i3°o2 L. W. V. 100— o fm. Temp, at the surface 8-2° C. 9 f ? i fc?.

"/s 96 St. 45 6i°32 L. N. 9°43 L. W. V. 100— o fm. Temp, at the surface 9-5° C. if?.

The Thor Expedition has taken this species at about 12 stations in the Atlantic south and
south-east of Iceland. Oul)' at the following 6 stations more than single specimens (generally adult
females) were found.

Thor 9/^ 1904 St. 178 63°o8 L. N. 2i°30 L. W. Yt. 750 M. Wire 16 f?.

'V7 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 150 f?; i fj*; 2 y? (V) 2 yc? (V).

^4/5 1904 St. 104 62°47 h. N. i5°03 L. W. Yt. 1500 xM. Wire 25 f?; 8 y? (V); i yd" (V).

^3/5 1904 St. 102 6i°4i L. N. i3°3i L. W. Yt. 15 M. Wire 20 f?; 2 y? (IV).

"Is 1904 St. 100 6i°2i L. N. io°39 L. W. Yt. 15 M. Wire 20 f?; 8 y (V).

'V7 1904 St. 124 6i°o4 h. N. 4°33 L. W. Yt. 1000 M. Wire 50 f ?; 10 y? (V) 3 yd" (V).

In Denmark Strait the Ingolf did not take any specimens, but the Thor brought it home from
the following stations.

Thor ^°/6 1904 St. T53 65°20 h. N. 27°: 2-5 L. W. Yt. 1000 M. Wire 36 f?; 5 y? (V|.
"k 1904 St. 154 65°27 L. N. 27°io L. W. Yt. 800 M. Wire 6 f?.

75 M. Wire 5f?; iy?(V); lyd'(V).

50 M. Wire i f$; i y?.
'S/6 1904 St. 150 65°5o L. N. 26°53 L. W. Yt. 400 M. Wire 2 f?.

The Thor has outside the Ingolf area south-west of the Faeroes caught the species at the
following stations.

Thor '5/6 1905 St. 82 5i°oo L. N. ii°43 L. W. Yt. 1200 M. Wire 8 f ?; i y? (V).

Yt. 800 M. Wire 35 f?; 6 i<^; 70 vc?; 25 yc? (V).
Vg 1905 St. 167 57°36 L. N. 9°55 L. W. Yt. 1500 M. Wire 20 f?.

300 M. Wire 2 f?.
200 M. Wire li^.

48

COPEPODA

% 1905 St. 72 57°52 L. N. 9°53 L. W. Yt. 1500 M. Wire 50 f?; 5 i^; 20 y? (V); 20 y c? (V); i yd" (IV).

2% 1905 St. 88 48°09 h. N. 8°30 L. W. Yt. 300 M. Wire 75 f?; 60 f (j'; 15 y? (V); 5 yc? (V).

"le 1905 St. 90 47°47 L. N. 8°oo L. W. Yt. 300 M. Wire 10 f?; 10 fc?; i y? (V); 2 yd* (V).

•7/^ 1904 St. II 959°54 L. N. 4°oo L. W. Yt. 500 M. Wire i y? (V).

From the material available it has been impossible to form any conclusive opinion about the
season at which Rhincalanus nasutus attains its full development By counting the specimens, col-
lected by the Thor Expedition with the young fish trawl from May, June and July 1904 and 1905, I
have attained the following figures. Even if we admit that the animals have been taken in two suc-
ceeding years in a limited and occasional quantity, I think that the following figures give some im-
pression of the relation between the males and females etc. About 100 f$, 20 y$ and a few young
males were taken in the month of May 1904 between 62°47 L. N. i5°05 L. W. and 6i°i5 L. N. 9°35
L. W. In June 1905 about 150 i% about 80 fc?, about 105 y$ and 50 yd* were taken between 57°52 L. N.
and 47°47 L. N., 9°53 L. W. and 8°o6 L. W. In July 1904 (6i°30 L. N. i7°o8 L. W.) a single sample
containing 150 f?, i fc?, 2 y? and 2 yc? was taken. Vg 1904 (62°49 L. N. i8°46 L. W. Yt. 500 M. W.)
5 females were captured. As the greatest number of males (60) against 75 females, of which three carried
spermatophores attached to the genital somite, were taken ^o^^ 1^05 St. 88 48°09 L. N. 8''30 L. W. Yt.
300—0, propagation probably took place in this locality.

Distribution. This species has been recorded from the Pacific between the vStraits of IMagellan
and the Gulf of California, from the western part of the Mediterranean and from the Indian Ocean
(one specimen only). Our knowledge about its distribution in the greater part of the Atlantic is very
scarce: "As far as concerns its distribution in the N. E. Atlantic, it may be regarded as an inhabitant
of the Atlantic current; its distribution to the north and east depending on the varying strength of
that stream" (Far ran p. 65). I think, that its occurrence on the west coast of Ireland, the Faeroe
channel, the Faeroe-Iceland channel, the North Sea south and south-east of Shetland, the Norwegian
Sea east of the Faeroes and east of Iceland (vSars), as well as at my own localities the south and west
of Iceland is easily explained in this way.

The vertical range of the species seems to be uniform from the surface down to more than
1800 meters (Far ran p. 66).

Esterly (1912 pp. 317 — 318) has on a somewhat scanty material drawn the conclusion that
there is indication "of a movement of the greater proportion of the individuals from the neighbour-
hood of 200 fathoms upwards to above 100 fathoms at night".

6. Eucalanus elongatus Dana.
(PI. I figs. 5 a — d; text-figs. 9 a — f).

1S52.
1877.
1892.
1894.

1895-
1898.

Calanus elongatus u. sp., Dana.
Eucalanus elongatus Dana. Streets, p. 139.

— — — Giesbrecht, pp. 131, 149.

— spinifer n. sp. Scott, p. 29, pi. I, figs.15— 23.

— elongatus Dana. Giesbrecht, p. 248.

— — — Giesbrecht &Schmeil, p. 20.

1898. Eucalanus elongatus Dana. Aurivillius, p. 29.
1901. — — — Cleve, p. 6.

1903. — — — J.C.Thompson, p. 15.

1904. — — — Wolfenden, p. 127.

1904. — Atlanticus n. sp. Wolfenden, pp. 113— 114,

pi. IX, figs. 3-4.

COPEPODA

49

1905. Eucalanus elongatus Dana. Esterly, p. 131 — 132, figs. 190S. Eucalanus elongatus Dana. v. Bremen, p. 15, fig. 10.

6 a — d. 1908. — — — Farran, p. 21.

1905.

1905-
1906.
1906.

Th. Scott, p. 222.
Farran, p. 30.
Pearson, pp. 6 — 7.
G. O. Sars, p. 2.

1908,
1910.
1911.

— Wolfendeu, p. 29.

— Farran, pp. 93—94, pi. XIV.

— Wolfenden, p. 204.

Description, f?. Size: 6-5 mm. The females scarcely differ from Giesbrecht's description.
No glandular pores were observed in the natatory limbs.

The labrnm proper, which is suddenly raised from the region lying in front of it, is by a
transverse groove divided into an anterior and a more raised posterior portion; the latter is divided
into three hairy lobes, a median and two lateral ones ' ■^

(text-fig. 9 a). The oral surface (fig. 5 a) shows a structure
similar to that found in Rhincalanus , but the two first
groups of the longitudinal series consist of fairly long and
slender bristles. In front of as well as behind the transverse
bar the skin is beset with a dense group of strong granules.
In front of the trebly divided lamina labiaUs (fig. 5 b) a
median longitudinal row of long and a lateral one of very
delicate setae are observed; in the middle a row of very
short hairs is found on each side, single behind and
double in front. Between the serrulae 6-dentatae a longi-
tudinal lateral series, a median group and more posteriorly a
transverse group of short setae are found ; behind the serrnla
an oblique group was seen. The area labialis possesses a
central group of hairs between the labial lobes, parti)'

continued on the latter, which bear four fairly regular
rows of hairs.

Text-fig. 9. EiicaLanns elongatus Dana.

a. (to the left above) fj. Labrum etc. X 18.

b. f?. Abdomen X iS.

c. (to the right I fd". Labrum etc. X iS.

d. fd'. Abdomen X 18.

e. Y9 (St. V). Abdomen X iS.

f. (to the right beneath). Yd" (St. V) X 18.

fc?. Size: 4-5 — 5 mm. The fifth thoracic somite is better marked out, and the lateral corner is
less produced than in the female. The head is in front of the transverse groove more strongly convex
(text-fig. 9c) and the labrum is lower; its oral surface is smooth; the labial appendages are lower.
The intestine is well developed with the usual convexity and coecal sacs.

The oral appendages are, as shown by Giesbrecht, greatly reduced. The legs of the fifth
pair (fig. 5 c) are more slender than figured by Giesbrecht; the left leg was, except in two spec-
imens, the longer. In a single male the terminal segments of the fifth pair possessed a small median
hair in addition to the terminal one. The fifth pair of the young male has the left leg a little longer
than the right; the Re is divided into two distinct segments, of which the latter bears two long
bristle^ (fig. 5 f, cf. Wolfenden PL IX, fig. 3); in a single young? male the number of setae in the
terminal segment was 3 instead of 2 (fig. 5 d) and in another young (?) male the structure was, as seen
in fig. 5 e, more like that of the mature male.

J? (V). Size: 4-5 mm. The lateral corner of the last thoracic somite is like that of the fc?.
The urosome consists of three somites, as the two basal ones (text-fig. 9 e) are fused in most specimens

The Ingolf-Expedition. III. 4. 7

CO COPEPODA

and slightly produced below. The anal somite is fused with the furcal rami, of which sometimes the
left and sometimes the right is the longer. The structure of the legs and of the labrum is scarcely
different from that of the female.

Jc? (V). The male of this stage is scarcely different from the female except for the four
abdominal somites (text-fig. 9 f) and well developed fifth pair of legs, as previously described. Wol-
f end en (1904 p. 113) has, with some doubt established the yoiing male of this species as a new one
Euc. atla7iiicits, because "the larger furcal segment and longest tail seta are on the left side, instead
of the right side", and on account of the not retrograded oral organs.

As, however, the former assumption is wrong, because not only males and females but also
young specimens have the longest furcal branch now on the right and now on the left side, and as
the latter is a general phenomenon in the young males, the species must vanish.

J$ (IV). Size: 3-8 mm. In general structure this stage is like the preceding one, but the urosome
consists of 3 somites, of which the two first are of almost equal length and distinctly shorter than
the third one, which is fused with the furcal rami, on the left side being the longer in both .specimens
examined. The ovaries were well developed though less so than in the preceding stage.

Occurrence. The Ingolf has taken this species only at a single station in Denmark Strait.
27/6 1896 St. 95 65°i4 Lat. N. 30^^39 Long. W. V. 200— o fm. Temp, at surface 7-8° C. 10 f?.
By the Thor it has been taken at the following stations.

Thor '9/6 1904. St. 152. 65^00 Lat. N. 28°io Long. W. Yt. 1000 M. Wire 35 f?; i yc? iV).

Yt. ? 90 f?.

2% 1904. St. 153. 65=^20 Lat. N. 27°i2-5 Long. W. Yt. 800 M. Wire if?.
2751904. St. 154. 65^27 Lat. N. 27°io Long. W. Yt. 800 M. Wire 30 f?.

Yt. 75 M. Wire 10 f ?.
18/6 1904. St. 150. 65°50 Lat. N. 26°53 Long. W. Yt. 400 M. Wire 3 f?.

The Ingolf, in the Atlantic south of Iceland, has caught the species at 6 stations, and the
Thor at 7 stations.

Ingolf '7/6 1895. St. 18. 6i°44 L. N. 30''29 L. W. V 200— o fm. Temp, at surface. 10° C. 15 f?.

'6/61895. St. 17. 62°49 L. N. 26°55 L. W. V' 200— o fm. — - — 9-1= C. if?.

3/6 1896. St. 68. 62^06 L. N. 22°30 L. W. V 100— o fm. — - — 87° C. i f?

'8/5 1896. St. 54. 63°o8 L. N. 15^40 L. W. V. loo-o fm. — - — 9-0° C. 10 f?,

'3/5 1896. St. 49. 62°o7 L. N. i5°07 L. W. V. 100— o fm. — - — 9-3= C. 40 f?

'Vs 1896. St. 47. 6i°32 L. N. i3°4o L. W. V. lOO-o fm. - - — io-6° C. 35 f?

Thor 9/^ 1904. St. 178. 63°o8 L. N. 21^30 L. W. Yt. 700 iM. Wire 85 f?.

'V7 1903. St. 167. 63^05 L. N. 2o='o7 L. W. I f?.

""n

1904. St. 180. 61^34 L. N. 19^05 L. W. Yt. 1800 M. Wire 8f?.

'/g 1904. St. 285. 62°49 L. N. i8°46 L.,W. Yt. 500 M. Wire 8 f?.

"/y 1904. St. 183. 6i°3oL. N. i7°o8L.W. Yt. 1800 M. Wire about 350 f?.

V9 1904. St. 286. 6i°49 L.N. 14^11 L.W. Yt. 1800 M. Wire 10 f?.

Yt. 15 M. Wire i f?.

COPEPODA

51

In the Iceland-Faeroe channel, the Ingolf has taken it at 3 stations and the Thor at 6 stations,
one from the month of Jnl}- with a single female, and 5 from Ma}'.

Ingolf 15/5 1896. St. 52. 63°57 h. N. i3°32 L. W. V.' 200—0 fm. 83° C. 2 f?.

2% 1896. St. 57. 63°37 L. N. 13^02 L. W. V.' 100— o fm. 8-2° C. 9 f?.

'Vj 1896. St. 45. 6i°32L. N. 9°43L. W. V.' 100— o fm. 9-1=0. 151"?.

Thor ^3/5 1904. St. 102. 6i°4i L. N. i3°3i L. W. Yt. 15 M. Wire 100 f?.

"/j 1904. St. 100. 6i''2i h. N. io°39 h. W. Yt. 180 M. Wire 15 f?.

Yt. 15 M. Wire 20 f?.

"/s 1904. St. 99. 6i°i5L. N. 9°35L. W. Yt. 1000 M. Wire 75 f$; i y?.

In the Atlantic outside the Ingolf area a big number of specimens, males as well as females,
were found.

Thor '5/6 1905. St. 82. 5i°ooL. N. 11=43 L.W. ^^^- 1200 M. Wire 500 f?; 28 y? (V); 100 yd" (V);

2 y? (IV).
Yt. 800 M. Wire 50 f?; 10 y? (V); 10 yo" (V);

2 y? (IV).
V9 1905. St. 167. 57^>L.N. 9°55L.W. Yt. 1500 M. Wire 25 f? ; i yd" (V).
8/6 1905. St. 72. 57°52L. N. 9°53L.W. Yt. 1500 M. Wire 2 f?; 12 fd*; 15 y? (V); 16

yc?(V); iy?(IV).
^°/6 1905. St. 88. 48=00 L.N. 8=30 L.W. Yt. 300 M. Wire 351?; 3 fd"; iy?(V); i yc?

(V); 2 yd" (IV).
^761905. St. 90? 47°47L.N. 8=00 L.W. Yt. 300 M. Wire 451?; 17 fd"; 9y?(V); 5

yd-lV).

It is rather curious that a large number of adult females, but only three young animals, from
three stations, were taken in the numerous samples brought home by the Ingolf and Thor from 31/^
— % north of 61° Lat. North. At four southern stations (^6 — ^Ve 1905) the Thor gathered mature males
and young animals in addition to numerous adult females.

Distribution. This species has been recorded from the Mediterrenean, the Indian Ocean, the
Pacific between 61° L,at. N. and 33° Lat. S., and the North and South Atlantic (as far south as 47°
Lat. S. 40° Long W.).

In the North Atlantic (cf. Farran PI. XIV) it has been found on the south and west coast
of Ireland, in the Faeroe channel, north and east of Shetland and occasionally in the North Sea as far
east as the coast of Norway. "In point of number it is generally scarce. Vertically it is recorded
from the surface down to 4000 meters." Esterly (1912 pp. 295 — 300) has on an extensive material
made it probable "that the species is more abundant and more frequent above 50 fathoms by night
than by day."

52

COPEPODA

7. Eucalanus Attenuatus? Dana.
(PI. I figs. 6 a — c; text-figs. 10 a— e).

1849. Calanus attenuatus n. sp. Dana.

. Eucalanus attenuatus Dana. Dana.

1S92. — — — Giesbrecht, pp. 131.

1894. — — — Th. Scott, pp. 28— 29.

1S95. — — — Giesbrecht, p. 24S.

1898. — — ' — Giesbrecht & Schmeil, pp.

20 — 21.

1 901. — — — Cleve, p. 6.

1903. — — — Norman, p. 135.

1903. — — — Cleve, p. 362.

1900. — — — Wheeler, p. 167.

1903. — — — J. C. Thompson & A. Scott,

pp. 242.

1903. Eucalanus attenuatus Dana. J. C. Thompson, p. 15.

1905-
1905.
1905.
1906.
1 90S.
1908.
1909.
1911.
1910.
1912.

Wolfenden, p. 996.

G. O. Sars, p. 2.

Esterly, p. 133, figs. 7 a— c.

Pearson, p. 7.

Farran, p. 22.

V. Bremen, p. i5, fig. 12.

O. Pesta, p. 21.

O. Pesta, p. 20.

Steuer, p. 21.

Sewell, p. 357.

Description y$. (Stage V). Length: anterior division 3-34 — 1-26 = 4'6; nrosome 058; total

length 5-18 mm. Tlie head i text-figs. 10 a — b) is like that of Rhincalanus ?iasutus triangularly produced in

•' '' " lateral as well as iu dorsal view. The fifth thoracic somite (text-fig.

IOC — d) is fairly well marked out, especially dorsally, and its lateral
corners are slightly produced and rounded. The rostral filaments
(text-fig. 10 e) are long and slender, and placed on a long bifurcate
basal portion. The urosomi\ which is scarcely one sixth as long as
the anterior portion, consists of three somites. The first (I <^ II), which
does not show any trace of receptacula seminis, is longer than the
two following combined; the fourth somite is completely fused with
the furca, which has the longer branch on the left side. The St. 2
sin. is distinctly longer and more powerful than the other setae.

The structure of the mouth appendages and natatory legs
scarcely shows differences of any importance from Giesbrecht's
description; the Ri 2 of the maxillipeds has only 3 instead of 4 Si.
No glandular pores were observed in the four pair of legs.

The labriim is in lateral view like that of Euc. clongatus

Text-fig. 10.

Eucalanus attenuatus Daua. YQ (stage V}.

a. Head in lateral \-iew X iS-

b. Head in dorsal view X iS.
c— d. Abdomen in lateral and dorsal though less produced. The Oral surface differs from that of the other

view X 1 8.
e. Rostral filaments X 27. species i) by anterior group of minute spines laterally near free

margin, and 2) by the different number and arrangement of three first groups of spines in longitudinal

series, as seen by comparing figures 5 a and 6 a; the structure of the three posterior groups and of the

transverse rows are scarcely different from that of Euc. clongatus. About the small differences existing

in the structure of the labium etc. I refer to fig. 6 b.

Yc? (Stage V). Length : 5 mm. The lateral corner of the fifth thoracic somite is less produced.

The urosovic consists of four somites, of which the first one is i-2 as long as the second, which is

again 1-3 as long as the third and fourth. In this species the fifth pair of legs (fig. 6 c) shows, as a

whole, more similarity to that of the adult male of E. attenuatus than in E. clongatus. The right leg

is the shorter, and the segments are more attenuated than in the mature male.

COPEPODA

53

Remarks. IMost probably the specimens examined ought to be referred to Eiic. attcnuatus Dana
in spite of a more produced forehead than in original specimens, and of greater size (Giesbrecht f?:
4-2— 4-85 mm.)- The Thor Expedition has taken the species at the following two stations

11/7 1904 St. 183 6i°30 L. N. 17^08 L. W. Yt. 1800 M. Wire i y?; i yd".
8/6 1905 St. 72 57"52 L. N. 9°53 L. W. Yt. 1500 I\I. Wire i y $.

Eucalanus atteniiatus has been recorded from the Pacific, the Mediterranean, the Indian Ocean
and the Atlantic. In the North Atlantic on the west coast of Ireland it has been found as far north
as 54°57 Lat. N. io°5i L. W. at about 700 fathoms.

8. Eucalanus crassus Giesbrecht.
(PI. I fig. 7; textfig. II).

i888. Eucalanus crassus n, sp. Giesbrecht, p. 333.

1S92.
1898.
1901.
1902.
1903.

1903.
1904.
1905.

Giesbr. Giesbrecht, p. 132, pis 4. ir, 35.

— Giesbrecht & Schineil, p. 22.

— Cleve, p. 6.

— Wolfenden, p. 361.

— J. C. Thompson and A. Scott,

p. 242.

— Cleve, p. 362.
Wolfenden, pp. 127— 12S.
Wolfenden, p. 996.

1905. Eucalanns crassus Giesbr. Th. Scott, p. 222

1905.
1905.
1905.
1906.
190S.
1 90S.
1909.
1912.

G. O. Sars, p. 2.

Esterl_v, p. 134, fig. 8.

Farran, p. 30.

Pearson, p. 7.

V. Bremen, pp. 16 — 17; fig- I3-

Farran, p. 22.

A. Scott, p. 19 — 20.

Sewell, p. 357-

Description, f?. Length: 37— 4-0 nmi. The basal fused portion of the rostral filaments is com-
paratively longer than figured by Giesbrecht (t. 35, fig. 26). The last thoracic somite, which is well
marked out, is somewhat rounded (text-fig. 11). The abdomen consists of 3 somites only; the receptaculum
seminis is large. The coecal sacs on each side are divided into smaller parts (fig. 7). In the
structure of the appendages a feature of interest was observed in the structure of the
external process of the basal segment of Ri, pes I, which is produced into a distinct
point not seen in Giesbrechts fig. 29 taf. 11. No glandular pore was observed.

The labrum is, in appearance, like that of Epical, clongatus, but the distance

to the insertion of the antennulae is comparatively shorter, and by a transverse groove

divided into an anterior and a posterior better raised part. The oral surface of the

labrum is most like that of Eiic. attenuahis, but differs somewhat by sharp distinction

Text-fig. II.
between median and lateral groups of marginal bristles. The two first groups of the Eucalanus crassus

longitudinal series are partly fused and convex towards the middle. Around the first Giesbr. f 9. Ab-
* r J domen in lateral

muscular spot a transverse group of granules is seen. The structures of the labium view x 3°-
are in the main similar to those of the species mentioned.

Occurrence. The Ingolf Expedition has not taken this species, but it probably belongs to the
area, as the Thor Expedition has taken it at

2% 1905 4S°05 Lat. North 8^29 Long. West Yt. 300 M. Wire i f?.

31/8 1905 St. 167 57°46 Lat. North 9°55 Long. West Yt. 1500 :\I. Wire 3 f ?.

54

COPEPODA

Distribution. This species has been recorded from the Mediterranean, the Indian Ocean, the
Pacific and the Atlantic. It has been found several times in the Fseroe channel and on the west
coast of Ireland as far north as 56°! i L. N. 9°50 L. W.

Paracalanidae.

Paracalanus parvus Claus.
(Text-figures 12 a — f).

1S63. Calanus parvus n. sp. Qaus, p. 173.

1864. Paracalanus par\-us Claus. Boeck, p. 233.

1905. Paracalanus parvus Claus. J.C.Thompson&A. Scott, p. 243

1S92. —

1S92. —

1S94? —

189S. —

189S. -

1899. ~

1899. -

1900. —

1900 —

1901. —
igoi —

1901 —

1902. —
1902. —
1902. —

1903 —

Cauu, p. 169, pi I, figs. I — 12.
Giesbrecht, pp. 164 — 171. taf.

I, 6 and 9.
Th. Scott, pp. 26—27, pl- I

figs. 9-14.
Aurivillius, pp. 29 — 30.
Giesbrecht & Schmeil, p. 24.
Th. Scott, p. 24S.
Brady, p. 32.
Th Scott, p. 3S3.
Wheeler, p. 16S, figs 6a — c.
Th. Scott, p. 350.
Cleve, p. S.
Brady, p. 32.
A. Scott, p. 402.
Wolfendeu, p. 361.
G. O. Sars, pp. 17— iS pis VIII

—IX.
Jensen, Johansen and Le\-in-
sen, p. 303, tabel I.

1903-

—

—

— Cleve, p. 367.

1904.

—

—

— Cleve, p. 194.

1904.

—

—

— Wolfendeu, pp. 129—130.

1905

—

—

— var. boreaUs n. var. Wolfendeu,

pp

997— 99S, pl. 96 figs 7— II and 16.

1905-

—

parvus

Claus. G. 0. Sars, p. 2.

—

—

— Farran, p. 30.

—

—

— Esterly, pp. 140— 41, figs 12 a — e.

1906.

—

—

— var. perplexus u. var. Norman

& A. Scott, p. 127 pl. XII figs. 1—2.

1906.

—

parvus

Claus. Pearson, p. S.

1906.

—

—

— T. Scott, p. 29S.

1908.

—

—

— V. Bremen, p 20 fig. 17.

I90S.

—

—

— Farran, p. 22.

1909.

—

—

— A, Scott, pp. 27—28.

I9I0.

—

—

— Farran, pp. 61 — 63.

I9I0.

—

—

— Kraeeft, p. 77, taf. i figs.

I9I0.

—

—

— Steuer, p. 22.

I9I2.

—

—

— Sewell, p. 358.

Description, fj. Size: 0-84 — i-o mm.

In contrast to Giesbrecht the head and the first thoracic somite are completely fused. The
niouthlimbs are scarcely different from Giesbrecht's description. In the structure of the natatory
legs, however, fairly well marked differences are found, especially in the armatures of the basipodites
and endopodites; in these respects they fairly well agree with Sars' description, but especially with
that given by Wo If end en for his P. parvus variet. horealis. In Sars figure, Pl. IX, the first segment
of the exopodite of the first pair of legs has a minute spine; in all my specimens this spine is sub-
stituted for by a bundle of fine hairs as seen in Giesbrecht's Taf. 9 fig. 31. Glandular pores are ob-
served at the base of the exterior spines of the exopodites (at least in the second pair of legs).

Between the mouth and the rostral filaments the usual elevations are found; I was not able
to see any setae along the hinder margin of the labrum. The arrangement of hairs on the oral sur-
face of the labrum is similar to that of Pseudocalanus. The first group, which is convex outwards,
and oblique, consists of about 10 short hairs in a single row; this group is followed by an almost
straight row of about 25 very short hairs; most orally, and fairly well separated from this group, 20
hairs are placed in a S-shaped group. Laterally to the first group two parth- transverse groups of

COPEPODA

55

fairly long setae, slightly convex inwards and posteriorly, are found. The median circular spots and
transverse series of hairs were not observed. The lamina labialis shows three serrations, of which
the median is the smallest. The scrrula 6-dentata is found as usually; the arrangement of the setae
was not examined in detail.

i$. About the description of the mature males I refer to Sars and Giesbrecht. Size: 07
— I -02 mm.

Y$— J" (St. V). Size: c? o-8o mm. (O.Exp. 1900); ? (o-6i -j- o-i8) = 079 mm. (Ingolf 96 Cyl. 45).
The shape of the bod)- is in the main like that of the mature female, but the head and the first
thoracic somite are fairly well separated,
and there is an indication of limitation
between fourth and fifth thoracic somite.
The first abdominal somite is, at least in
most specimens, distinctly produced below
(text-fig. 12 b). The oral appendages are
scarcely different from those of the mature
females; the natatory legs, however, show a
few differences; a very short Se Re II is
present in the first pair of legs. The ex-
terior margin of the last segment of exo-
podite is smooth in the fourth pair of legs,
but, as usual, dentated in the third pair.
The fifth pair of legs appears more clumsy
with shorter terminal spine.

The male differs from the female
by the less prominent first abdominal somite, and by the better developed asymmetrical fourth pair
of legs (cf. Canu) (textfigs. 12 c — d).

Y$— c? (St. IV). Size: (0-48 -{- 0-14) = 0-62 mm. This stage is easily distinguished from the pre-
ceding one by the number of abdominal somites (3 only). As in the other stage, differences are found
in the less prominent fifth pair of legs in the males (cf. text-figs. 12 e — f).

Of the copepodites (stages I — III) I am not sure of having observed any; according to Ob erg
these as well as the larval forms are rather difficult to distinguish from those of Fsetidocalamis elon-
gatus] they are, however, smaller and more clumsy, and have the exopodite and the endopodites of the
antennae of almost equal length. From Ingolf St. 62 (Apst. 14) I have examined a young specimen
(St II) 0-6 mm. long and one (St. I) 0-48 mm. long, which on account of the long endopodite of the
antenna perhaps ought to be referred to this species.

Variation. In a single mature female? (F. 389 0. Exp. 1900), the size of which was (o-68 -f 0-2)
= 0-88 mm. the left leg of the fifth pair consisted of four segments as in the immature male, while the
right consisted of two segments only. A somewhat smaller female from the same locality had both pair
of usual structure. Bay has taken 3 specimens with the left leg somewhat longer than the right.

Text-fig. 12. Paracalanus parvus Claus.

a. f9 Genital somite in lateral view X 90-

b. yQ (Stage V). Abdomen X 90.

c. yo" (Stage V). Abdomen X 90.

d. j'c? pes V in anterior view X c. 400.
e— f. y9— o' (Stage IV). .\bdomen X 90.

g. f Q. Abnormal specimen with well developed pes V X 9°.

56

COPEPODA

though consisting of the same number of segments. Normann &: Sco tt have with reservation described
a female with the right fifth foot three-segmented, and longer than the left as P. /. var. pcrplcxus.

Remarks. The specimens, which have been examined all belong to the northern variet}- (var.
borealis Wolfenden p. 997), and are fairly well distinguished from the Mediterranean form described b}-
Giesbrecht. A. Scott (1909 pp. 27 — 28) thinks that the differences are rather unimportant, in that
he is scarcely right. Detailed examination of a good many specimens from different localities especially
from the Mid-Atlantic is necessarj- to decide the question whether the observed differences are specific
or due other reasons.

Occurrence. The Ingolf Expedition has taken this species from 7 stations to the south and
south-east of Iceland as well as in the Fseroe channel. It has been taken as far west as at St. 84
Long. W. 25°24, Lat. N. 62°58; the only station farther north where is has been taken by the Ingolf
Exp. is St. 101 (Apst. 47 9/7 1896 4 p. m. 66°23 Lat. N. i2''05 L. W. 2 f$) north-east of Iceland. From
the East Greenland Exp. 1900 it was once taken in Denmarks Strait as far north as 65°36 L. N. 3i°32
L. W. 9/g 2 a. m. F. 31S. The comparatively few other localities, in which it has been taken by this
Expedition lies between 62°o6 Lat. N. and 59° 20 L. N., and 2i°ii L. W. and o°52 L. W. At the fol-
lowing stations more than single specimens of this species were captured.

Ingolf 17/, 96 St. 84 62°58 L. N. 25=24 L. W. Cyl. 9 f?; 3 y? (V); 2 yc? (IV).
19/8 95 6i°02 L. N. o°4o L. W. PI. 11 f?; 2 yd" (V).

'7/8 96 60^28 L. N. 0^20 L. E. Cyl. 9f?; i fc?; 3y?(V); i yd" (V); i y?(IV); i yd" (Vj.

0. Exp. 1900 24/, 6 p. m. 61% L. N. 16^26 L. W. F.389 2 f?; 2 fd"; 6 y? (V); 2 yd" (V).
25/9 2 p. m. 6o°29 I- N. i2°io L. W. F.399 7 f?; 3 yd" (V).

8 a. m. - - F.396 3 f?; 2 y? (V); 2 yd" (V).

It is an interesting fact that almost all the collections of this species are from the month of
September (O. Exp. 1900 %— 3% 16 Stations) or from the month of August (Ingolf Exp. 1895—96
9/8 — '7/8 8 Stations). In the month of May a single >oung male (^/^ 96 Cyl. 2 57°54 Lat. N. 6"'27 L. E.)
was taken, and in the month of July (Cyl. St. 84 ^Tji, 1896 62°58 Lat. N. 25=24 Long. W.) 9 mature
females, 3 young females (stage V) and 2 joung males (stage IV) were taken. Young animals (St.
IV — V) were also captured as late as 27/3 1896 and ^^/g ^QOO- The fact that this species was rarely
taken in several collections in the monthes of May and June 1895, 1896 and 1900 in the same regions
in which it was found in August and September indicates a certain periodicity in its occurrence, as
shown by Far ran, in several of the localities explored b)- the International Investigations (1910 pp.
61—62). The average salinity for this species, which generally is swarming at the surface is rather
low in the Kattegat (19-33 7oo, Temp. 10-33° C-), but a good deal higher in the English Channel (35-26 7oo,
Temp. 13-28° C). According to Cleve (1901) the salinity in the Arabian Gulf Ues between 35-77 °/oo and
36-20700 (Temj). 26-7 C.) and in 1904 between 35-40 and 40-70700; the maximum temperature at which
it was found in the Indian Ocean is 29=35 C. (Cleve 1901 p. 8).

Distribution. Assuming the specific identity of the northern and tropical forms we find records
of its occurrence from the Mediterranean, the Black Sea, the Red Sea, the Arabian Sea, the Indian
Ocean as far South as New Zealand (Brady 1911 p. 32), the Malay Archipelagos (A.Scott 1909) the

COPEPODA

57

Pacific between 6i^ N. and 52° N., between 10° S. and 55^ S. west of South-America, and 108° L. W.
Equator (Giesbrecht 1892) and off California (Esterly 1905). In the North Atlantic it has been
recorded on the west side off Woods Hole (Wheeler 1900) and on the east from the Faeroes to Gibraltar.
According- to Scott (1894) it is fairly common in the Gulf of Guinea as far south as the Congo;
Wolfenden shares, probably rightly, the opinion that the species which the mentioned author
describes as P. parvus really is Paracalanus aculcatns Giesbr., which represents this species in the
South Atlantic (191 1, p. 203). In addition to all these localities this species is found in the southern
part of the Baltic, the Kattegat and the North Sea.

Pseudocalanidae.

10. Pseudocalanus minutus Kroyer.
(Plate I fig. 8; text-figs. 13 a— f and 14 a— c).

1S45 — 47. Calaiius minutus u. sp. Kroyer, T. 41 fig. 4.

1S49. Calanus minutus Kr. Kroyer, pp. 543—44, 552.

1864. Clausia elongata n. sp. Boeck, p. 234.

1872. Pseudocalanus elongatus Boeck. Boeck, p. 37.

1892. — — Boeck. Giesbrecht, pp. 197 — 200,

taf. 10.
1892. Clausia elongata Boeck. Canu, pp. 170— 171; pi. II, figs.

I — 13-
1S97. Pseudocalanus elongatus Boeck. Vanhoffen, p. 278, pi. I,

fig. 6.
1898. — — — Giesbrecht & Schmeil,

p. 28.
1898. — — — Aurivillius, pp. 69—70.

1900. — — — G. O. Sars, p. 69.

1900. — major n. sp. G. O. Sars, pp. 69—72, pi. XX.

1901. — elongatus Boeck. Th. & A. Scott, p. 339.

1902. — — — Mrazek, pp. 507 — 508,

figs. 5-6.

— — — Th. Scott, p. 450.

— — — Wolfenden, p. 361.

— — — Norman, p. 135.

— — — I. C Thompson, p. i5.

— — — G. O. Sars, pp. 20—21,

pis X— XI.

— gracihs n. sp. G. O. Sars, pp. 154 — 155,

pi. I (Suppl.).

1903. Pseudocalanus elongatus Boeck. Jensen, Johansen, Le-

vinsen, p. 304, tabel II.

1902.
1902.

1903-
1903.

1903-
1903-

1903.

1904.
1905-
1905-
1906.
1906.
1907.
1907.
1908.
1908.

1910.

1910.
1911.
1913-

1913-

— — J.CThompson&A.Scott,

p. 244.

— — Wolfenden, p. iii.

— — G. O. Sars, p. 3.

— — Farran, p. 30.

— — Pearson, p. 10.

— — Williams, p. 640.
major G. O. Sars. Koefoed&Damas, p. 407.
gracilis G. O. Sars. Koefoed&Damas, p. 406.
major G. O. Sars. v. Bremen, p. 25, fig. 22.
elongatus Boeck. v. Bremen, p. 25, fig. 23.

— — Farran, p. 28.

_ _ Oberg, pp. 48-49, 56-57

taf. I and VI fig. 3.

— — Kraeeft, pp. 67, 77. 79,

taf. I figs. 13 — 21.
— ■ — Steuer, p. 22.

— — Farran pp. 63 — 65.

— — Stephensen, pp. 71 — 72,

pis 4—5-

— — Stephensen pp. 312 — 13.

Synonymy. As Kroyer has described and figured a )oung male of his species, it is perhaps
not so curious that the different authors have not realized that it is identical with Pseudocalanus elon-
gatus Boeck. Kroyer's description and figure are however so good, that scarcely any other species from
the Arctic Sea has a pernultimate stage to be confounded with it. As I have had the opportunity of
examining Kroyer's original specimens, it is quite evident to me, that the two species are identical;
the three examined specimens belonged all to the penultimate stage (ic? -f 2?); they were in the shape
of the head most ahke Ps. gracilis, and were of middle size. According to the general rules of nomen-
clature the name Ps. elongatus ought to be changed to Ps. minutus Kr., if the three forms are referred
to a single species.

T!ie Ingolf-Expeditton. III. 4.

58

COPEPODA

Introductory Remarks. The material which I have examined of this species has been very
big, as it is one of the most abundant and widely distributed plancton-copepods of the northern seas;
it was therefore quite necessary for me to try to solve the question, whether different or only a single
species alike to Pseudocalaniis minutus exist; unfortimately the result of my investigations is not quite
satisfactory. Sars has been the first, who has pointed out that different types exist, and taking the
scanty material into consideration he was quite right in establishing the three species Ps. clongatus
Boeck, Ps. major G. O. S. and Pseudocalanus gracilis G. O. S. No naturalist has later on tried to solve
the question, scarcely touched it'; most of them have examined specimens from southern regions and

'' have scarcely been wrong in

referring them to the Ps. elon-
gatus Boeck (sensu strictu).
According to Sars the 3 species
are characterized in the fol-
lowing manner.

i) Ps. major G. O. S. Aver-
age length of $ 24 mm. Tlie
head is only slightly produced
anteriorly; the abdomen is half
as long as the cephalothorax.
The antennulae extend almost
to the middle of the abdomen.
2) Ps. clongatus Boeck (sens,
strict). The average length
is 1-4 ram. The head is only
slightly produced anteriorly; the urosome somewhat exceeding half the length of the anterior division.
The antennulae scarcely reach beyond the second caudal somite.

3) Ps. gracilis G. O. S. Average length 1-65 mm. The body is more slender and the head anteriorly
distinctly produced; the urosome scarcely exceeds half the length of the anterior division; the caudal
rami are comparatively narrower and more divergent. The antennulae reach to the end of the third
caudal somite. Legs considerably more slender than in the typical species, with both rami very narrow.
It will be noticed that in most characters, except in size, the Ps. gracilis differs almost equally
from the two other forms. The character found in the size and the length of the urosome is at
least of very relative value, as even from the same station (Ing. Nr. 31) ^ the following was observed:
Spec Nr. i 2-3 mm. with ant. division 2-5 x urosome, Nr. 2 I'S mm. ant. div. 2-5 x uros. (head of
gracilis type); Nr. 3 i-8 mm. ant. div. 2 x uros. (head elong. type); Nr. 4 17 mm. ant. divis.
2-5 X uros., Nr. 5 1-5 mm. ant. divis. 2-4 x urosome; Nr. 6 1-4 mm. ant. divis. 2-i x urosome; Nr. 7 1-2 mm.
ant. divis. 23 x urosome. The relation between the length of the urosome and anterior portion has

Text-fig. 13. Pseiulocalanus mintttits Kr.
a. f?. Head from the left X no. b--c. Y$ — o" (stage V) .A.bdonieu X 59-

d. Ycf (stage V) Pes V X 150. e. Yo" (stage IV) Abdomen X 59-

f. Yd" (stage IV) Pes V X 150.

» With the exception of Dam as and Koefoed, who have often been in difficult}- about the identification of the
specimens and p. 406 write "Ces deux especes, distinguees par Sars, ne sout peut-etre que des variations d'une seule forme".
- N. B. from this station was found copepodite (St. V) 17 mm. and cop. (St. IV) f4mm. long.

COPEPODA 59

also been examined at se\eral other stations (f. iust. Gnnolfsvig Iceland), where I often found that the
small specimens had the nrosonie comparatively longer (f. inst. ant. div. 1-9 x uros.), but with several
exceptions. According to Sars the anterior division of Ps. gracilis is comparativel}- more slender; I
found, certainly, that a specimen of t\-pus ?iiajor had the anterior division 2-3 as long as wide, one of
t\-pus gracilis 27 as long as wide, and one of typus cloiigahis 2-4 as long as wide, but as several
exceptions were found, I was not able to use this character. I first got the impression that the
characters found in the comparatively long antennulae and natatory legs in several specimens of
the typus gracilis were useful, but a stud)' of greater material made it evident to me that they
were too variable to be of any value. The feature which marks out some specimens as gracilis
i.s the curiously prominent forehead, which is in any case very seldom found in the biggest as
well as in the smaller specimens. But as all transitions were found between the different shape of
head, even in specimens which in other respects were most like gracilis, it was impossible for me to
accept more than a single species.

Description, f?. I was not able with certainty to find any secretory pores in the natatory legs.
The labruiii proper, which is the most posterior of a row of more or less prominent elevations
found behind the insertion of the rostral filaments (text-fig. 13 a), has along its hinder margin, on each
side, a group of fairly long hairs, and in the middle, somewhat in front, a hairy protuberance. The oral
surface of the labrum possesses four groups of short hairs, as seen in fig. 8 (PI. I). The lamina la-
bialis has along its posterior margin three indistinct rounded eminences ; orally the two usual longitudinal
series of fairly short hairs are observed, of which the more lateral is longer and with longer hairs.
Behind the lamina a transverse row of short hairs or teeth is observed and a similar but longitudinal
one is found inside the serrula 6-dentata. Between the labial lobes, which are covered with hairs, the
arrangement of which were not made out, about four groups of hairs are found, of which the hind-
most, which has longer hairs, stands more laterally. Between this and the lateral margin behind the
labial lobes 2 oblique groups of hairs are present.

Behind the area labialis proper is found on each side a large group of fairly long hairs in addition
to a few hairs more laterally, and in the middle a triangular group, placed more posteriorly and with
its hindmost, wider part fused with a rather irregular group of setae placed between the insertion of
the maxillae.

fc?. As far as the full-grown males, of which comparativelj- few were examined, were concerned,
I could not find other differences between the different specimens than that of size, varying from i-i
to 1-4 mm. Canu and Sars have given descriptions and figures of the rudimentary mouth limbs. In most
specimens an indication between the head and first thoracic somites was seen as figured by Canu as
well for the male as for the immature specimens.

Y. (Stage IV). Size: r2— rg mm. The last thoracic somite is generally more produced than
that of the mature females, and dorsally a more or less marked limitation between the two last
somites is found (text-figs. 12 b— c). The urosome is comparatively short and sometimes only one third
of the anterior division; according to Kraefft (figs. 15 — 18) the two first somites are better separated
in the males than in the females; generally no such differences were observed, but in some young
females, especially of the smaller "variety", the two first somites were somewhat produced below,

6o

COPEPODA

probably an indication of the final ecdysis. The mouth limbs are scarcely different from those of
mature females. The males are always easily distinguished from the females by the presence of the
well developed pes V (text-fig. 13 d) which consists of two basal segments and two terminal ones (Re),
which especially on the right side, are not always so well distinguished as figured by Canu (PL II fig. 6).
In this stage varieties similar to those of mature females but less marked were found.

Y. (Stage IV). Size: o-g — 1-4 mm. But for the presence of only 3 somites in the abdomen this
stage is like the preceding one, and shows similar differences between the two sexes (text-figs. 13 e— f).
Y. (Stage III). Size: 07 — 1-0 mm. This stage, of which Stephen sen has given figures of
all the limbs, shows no sexual differences, and is characterized by four natatory legs and two abdo-
minal somites.

Y. (Stage II). Size. 0-5 — 08 mm. This stage has three natatory legs and two abdominal
somites. The last copepodite stage as well as the larval forms was not with security found out; I
refer to O berg's description.

Variation. From Iceland I have examined a female (taken ^'^l(, 1902 by Ditlevseu in Heste-

reyrifjorde) with a spermatophor attached to the genital somite, in which a fairly well developed

" *■ ' fifth pair of legs was observed (cf. text-fig. 14 a— b).

The Ingolf Exp. (at St. 49 V.' 100 — o fm.) has taken
a full-grown female? alike the preceding but with
much longer pes V, of which the left is longer than
the right (text-fig. 14 c). The 0. Exp. 1900 (F. 451)
has taken a female with a right and left pes V of
almost equal length ; the Re III of left pair is rounded
and short, without terminal seta; the corresponding
segment of the rio-ht side is more elongate. From
Ingolf (St. 29 V 50 — o fm.) I have examined a
young animal ($?) with a rudimentary pair of legs, .

Text-fig. 14. Pseud, minuttn Kr., abnormal female.

Abdomen female with speraiatophor from Hestereyri-

fjord Iceland) x 67.

Pes V of same specimen X 160.

consisting of two short basal segments, and a rounded

c. (to the right) Pes V of specimen from Ing. St. 49.

small terminal segment. Boeck is the first who
has mentioned females with a fifth pair of legs
(1S64 p. 234), and Mrazek has published an interesting study on this topic. He has found a small
rudiment now and then, and sometimes a fairly well developed pair of legs; his figures of two spec-
imens are somewhat different from each other, but in structure mainly like my specimen from O.
Exp. Kraef ft has examined a female with a rudimentary fifth pair of legs. It is interesting, though
in no way surprising, that the organ in none of the 6 specimens in which its structure has been
described was alike another.

Occurrence. This species has been taken almost all over the area explored by the Ingolf
Expedition, as far north as Jan Mayen and the Diskoislaud; in the Atlantic it has not been taken
farther south than at the latitude of 63° North. By the East-Greenland Expedition it was only taken
at comparatively few stations, south east of the Faeroes 6i°o6 Lat. N. io°26 Long. W., in the Nor-
wegian Sea as far east as 1^04 Long. East (lat. 62°i6 North) and at 6°i2 Long. West (at 69°o6 Lat.

COPEPODA 6l

North), ill the Polar Sea as far north as 72^30 Lat. North (6^41 Long. West), along the east coast of
Greenland as far north as c. 70° Lat. N. In Denmark Strait, in the Atlantic (west of the Faeroes)
and in the fjords of Iceland as well as on the west coast of Greenland it has been taken by several
collectors.

In the following I am going to give an acconnt of the number of stations at which the diffe-
rent stages and partly the types of the species were taken at the different seasons.

West Greenland. In Davis Strait, on the west coast of Greenland, the Ingolf Expedition
1895, has taken mature females of Ps. uiajor^ at four stations from '/? — "/? ^895, Ps. gracilis at five
stations from ^'^/e—^^/y, and Ps. clongatus from a single stat. ^V?- O^ the copepodites (St. V) specimens
of Ps. major have been taken at 2 stat. (^^/e — 7?)) of Ps. gracilis at 3 st. (77—^7?) ^""^ ^^ ^^- elongatiis
at 2 stat. (7; — "/?); of the copepodites (St. IV) Ps. major was taken at 3 stat. [^^je — 77)1 of Ps. gracilis
at 2 stat. (6/7—277) and Ps. clongatus at 2 stat. (7?— "A)- At a single station (7^ St. 29, 65°i7 Lat.
North 55^42 Long. West) a single mature male was found, but at no station copepod. of younger
stages than the fourth were taken. In contrast to the Ingolf Expedition, by which most specimens
were taken in the open sea in vertical hauls in a depth of from 200—0 fathoms, Bergendal and
Lund beck have in 1890 taken a good many specimens at the surface and near the coast. On that
account, perhaps, almost all the specimens are most naturally referred to the Ps. clongatus type. From
"Jakobshavn" 2 mature males |from the same sample 50 f?; 5 y^ (V); 4 y$ (V); 3 yc? (IV); i y (III)]
were taken ■^'^/g, mature females were taken at 3 stations (^'/g — ^^l%\ young specimens (V) at same 3
stations and Cop. (Ill — IV) at a single stat. (^s/s) only. From Egedesminde 2 mature males were taken
^3/7 [from same stat. 6 f?; 2 y? (V); 2 yc? (V)], Vs zi^ [9 f?; 60 y? (V); 35 yd' (V) from same station] and
3 fd' '% [from the same stat. 12 f?; 9 y? (V); 2 y? (V); 5 y$ (V); i y<^ (IV); i y (III); i y (II)]; from the
same locality mature females were found eight times between -77 and '% and a single time ^/j^ night
[at this catch were taken 6 f?; 12 y?(V); 4 yc? (V); 6 y? (IV); 4 y$ (IV); 4y (III); i y (II)], young animals
(Vl seven times between 7; and '"/s and 9/jo, young animals (IV) 3/7, '% and 9/jo and Copep. (II — III)
only y/,0.

At Disco Bay Lundbeck has % taken 160 mature females, 3 mature males, 3 young females
(V) and 5 males (V), 3 young females IV and 13 copepodites (III) and Bergendal at the same date
100 ? (VI), I c? (VI) and 3 y? (V).

West of Iceland. In Denmark Strait and on the west coast of Iceland no specimens, which
were naturally referred to Ps. major, were observed; mature females of Ps. gracilis were only taken
at 3 stations (V.' 19-^°/, 1895) in the open sea and young ones (III — V) only '9/5, while specimens in
different stages, including mature males, of the Ps. clongatus s. s. were only found in "Dyrefjord" [30/5
1895. 6 f$ (partly with egg-balls attached to genital somite), 9 y? (V), 2 y? (IV), i fd*, 7 yS (V), i y$
(IV), 2 y (III) and s/^ 1896 i f?]. The sample from '9/5 1895 V.' 100— o. St. 8, 63=56 Lat. N. 24=40 L. W.
contained 100 f?, 2 y? (IV), 7 fd*, 2 yc? (V), i y? (IV) and 2 y (IV), and that from ^o/, 1895 V.' 100— o fm.
St. 9 17 f$ and 15 fcf.

North of Iceland. In the fjords north-west and north of Iceland A. Ditlevsen has ^5/3 1902, at
Hjalteneyri Ofjord gathered specimens of the clongatus type [i f?, 2 y? (V), i y? (IV); 2 yc? (IV); i y (III)]

62 COPEPODA

aud 2»/8 at Svavadilvig [2 f?, i y? (V); i yc? iIV), 3 yd* (V)]. Lundbeck has 25/. 1892 taken 14 f? (two
with egg-ball and one with spermatophor), 3 \? (\'), 2 yd" (V) at Skutulsfjord and ^s/g? in Gunolfsvig
(N. East Iceland) 50 f?, 5 y? (V), 10 yd" (V) and i yc? (IV).

South-West of Iceland. To the south-west of Iceland 10 mature females, 5 y$ (V), 3 mature
males and 5 young males (V) were found 's/g 1896, St. 80, P. 100 — o fm. 61^02 Lat. N. 29°32 Long. W.

South of Iceland. To the south of Iceland a single male was taken by the Ingolf Exp. (7/3
1S96, Cyl. 32, 63°45 Lat. N. 22^37 Long. W. 2 ?; 2^*); */« 1896 a mature female of Ps. gracilis^ and from
'3/, — 19/. 1896 at three stations females of Ps. elongafus were taken; of the latter young animals {\')
were taken at 3 stations i^j^ — 31/^), y^ (IV) at a single station (3i/j 1896) and young animals (III) 3°/^ 1895
and 31/5 1896. The East Greenland Exp. 1900 has taken a few mature and joung females south of
Iceland ^5/^.

In the Icelandish fjords adult males have been taken several times by different collectors. On
the north coast it was only taken once | Ingolf '/s 1896 Selvik in Skagafjord 65°58 L. N. i9°50 L. W.
PI. 4 y$ (V), I fc?, 5 yd* (V), 7 y^ (I\'). 10 y (III) aud 2 y (II)]. On the east to west coast males were
taken 3 times ('3/j. — 26/. 1902), and females as well as juniores (stage II — \) were in several samples
found common from '3/^. — 26/=;.

South-East of Iceland. In the Iceland-Fceroe channel south east of Iceland Ps. gracilis (f$)
were taken in four .samples between "/.=; — '''''5 1895 and ^o/. 1896, and Ps. elongafus (f$ — c?) in four samples
("/j— '% 1895 and 2% 1896); young auimals (IV — Vl were taken three times ("/-— 's/j 1895 aud ^o/^. 1896).
Several males were found in a single sample from "/^ St. i, V.' 50—0 fm. 62-30 Lat. N. 8°2i L. \V.,
including 140 f?, 23 y$ (V), 8 y? (I\'), 30 fc?, 20 yd* (V) and .5 y^ (IV). From St. 3, '^/j, \'.' 100— o fm.
II f$ and I fc? were found and from St. 4, '3/. 1895, V.' 100—0 fm. 64°o7 L. N. ii''i2 L. W. 37 f?, 3 y$ (\'j,
I y? (IV), 2 f(? and 4 yc? (V). From St. 57, ^o/, 1896, V.' 100— o fm. 63°37 Lat. North 13=02 Long. West,
I f?, I y^ (Vj and 2 fc? were secured.

North-East of Iceland. To the east and north-east of Iceland as far north as Jan Mayen
specimens (f$j of Ps. gracilis were found in four samples, taken between '°/; and ^5/^ 1896, and Ps.
clongatus in six samples ('°/j- — ^5/7); 3'0"ng animals (IV— V) of the former type from 3 Stat. {'"/z^^^V?)
and of the latter from 9 Stat. C"/;— ^5/7 1895); the following stage (III) was taken at 6 Stat. ('/^ — ^sy

The East Greenland Expedition 1900 has from ^^jb to ^j-j in the Norwegian Sea between 63'^i6
Lat. North i°i4 Long. East and 72^30 Lat. N. 6°4i Long. W. collected a few samples containing this
species (type: gracilis or elongahes) all taken at the surface (F. or G.).

The mature female was only taken once (^'/^ 12 p. m. F. 33, 64°i7 Lat. North o°5i LongWesti;
young animals (V) were taken in 7 samples, including that from the most northern station, >oung
animals (III — IV) were found in four samples. As the species was only taken in few specimens, in
altogether 7 samples, though one sample was taken each hour day and night from ^1/5 to '% as far
north as 74°28 Lat. North (i5°36 Long. West), there is good reason to regard it as extremely scarce
at the surface at the season and in the region mentioned.

The expedition has taken the Ps. elongahis a few times in Nansen's closing net.

COPEPODA 63

Viz: ^'/6 I p. m. 64°i7 L. N. 0=51 L. E. 75-50 fin. i f?; 3 y? (V); i y? (IV); i W; 3 Yc? (V); 3 Yc? (IV);

ly(in); ly(II).
40-10 fm. I f?; 6 y? (V); 5 y? (IV); 9 y^ (V); 9 yc? (IV); 7 y (III).
25/5 Jan Mayen 50—60 fm. 5 f$.

'/y 100 — 50 fm. I f$.

Johannes Petersen has "l-j 1901 at 73° L,at. North cmd 8" Long. East taken 60 f?, 99 y?
(V), 9 y? (IV), 72 yc? (V) and 5 yd' (IV) of Ps. gracilis.

East and South-East of the Fasroes. To the east and south-east of the Faeroes mature females
of Fs. gracilis were only taken 7/5 1S95 and ^5 1896, while those of Ps. clongatus were taken in 3
samples (S/g and "^/s 1895) and in 9 samples by Ingolf 1896 (■> 5— ''/s and i^^/g). Mature males were taken
Wj 1895 Cyl. 2 |59°i7 Lat. N. 3°26 Long. E. 3 f?; i ii\ 4/5 1896 Cyl. 4 |58°29 Lat. N. 5°o Long. E. 16 f?,
3 y$ (V), 2 y? (IV), 2 fd', 6 yc? (V), 2 yj' (IV), i y (III)], 5/. 1896 Cyl. 6 [59=18 Lat. N. 3°o8 Long. E. 5 f?,
I y? (IV), I fd', I y (III)I, 5/5 1896 Cj'l. 8 |6i°oo Lat. N. 0=10 L. E. 9° C. 33 f?, of which one with sperma-
tophor, 1 y? (V), i y? (IV); 8 fd", 6 yc? (V)], 'Wg 1896 Apstein 81 [63°45 Lat. N. 7°io Long. W. i fc?; x yd*
(IV); I y (III)l, '3/8 1896 Klakvig Ankerplads the Fseroes i fc?, '^/s 96 Cyl. 44 [60=50 Lat. N. 0=25 L. W.
6 f?, 8 y? (V), 10 y? (IV); i fd', 14 y$ (V), 8 yd" (IV); 4 y (III); i y (II)] and '^/g 1896 Cyl. 47 [59=40 Lat.
N. 2=12 Long. E. II f?, I y? (IV); i fc?; i y (III)]. Young animals (V) were taken 5/5 1895 and in 9 samples
1896 (-t/j— ^^/j; ^'^/g— '7/3), young animals (IV) only in 5 samples (4/5—^/5 and i?/,, 1896), jun. (Ill) in 3
samples (4/5, 6/5, '7/3 1896) and juniores (II) 4/5 and '^/g 1896.

E. Bay has ''/s 1891 58=03 Lat. N. 2=08 L. W. taken 50 f?, 31 y? (V), 16 y? (IV), 3 fd*, 16 yc?
(V), 19 yd* (IV), 9 y (III) and 2 y (II). .Mortensen has s/g 1899 at Kalbarsfjord, the Fseroes, 40—10 fm.
taken 3 females with spermatophores and Rink has i^/^ 1848 at the 0rkney Islands taken 6 f?, 4 y?,
3 fc? and 3 yd*.

If any conclusions with regard to the occurrence of the three mentioned types can be drawn
from the above, it must be that Ps. major is only found in the open sea in Davis Strait, probably
not at the surface, that Ps. elongatus is often found at the very surface, most common in samples
taken comparatively near the coast, though in no wise scarce in those from the open sea, and that
Ps. gracilis seems to be a more northern and more oceanic form.

Propagation. As it is generally recognised that the mature males of the pelagic copepodes,
especially in species in which the manducatory limbs are rudimentary, only live a comparatively
short time, we are right in concluding that the seasons in which we find mature males are those of
tlie propagation of the species; specimens with spermatophores attached to the genital somite and
with egg-balls indicate the same.

Mature males have been found south-east of the Faeroes Wj 1895 and in 4 samples 4/5—6/5 1896,
in the Iceland-Faeroe Channel at 3 stations "/j— '3/5 1895 and ^°\^ 1896, south-west of Iceland 's/g and
7/8 1896, in Denmark Strait at 2 stations '9/5—20/5 1895, in various Icelandish fjords, in 5 samples 3;,_
30/j 1895— 1902, at the Orkney Islands '8/3 1848; 3/^ 1899 a female with spermatophor was taken at the
Fferoe Islands; "/e 1891 mature males were taken south-east of the Fseroes; north-east of Iceland (as
far north as 66° Lat. North) mature males were taken ^5/^ 1895 (+ females with spermatophores)

64

COPEPODA

and "ie 1900. In Davis Strait matnre males were taken ^.j 1895 and at Egedesminde etc. in 6 samples
from ^-^'7— '''9 1890.

From the north of Iceland males were taken '/g 1896; from the Faeroes and the Norwegian Sea,
south-east of these Islands, they were taken in 5 samples from 7/8 — '''Is-

As only very few samples were taken from the explored regions at other seasons (from Norwe-
gian Seas none Jnne— July 1895 — 96), we do not know if propagating took place at other seasons.

Mature females were taken in Denmark Strait '9ij_3o;j 1895, in Davis Strait ^? 6— ^^ 7 1895 and
23/y— 6/g 1892, south-west of Iceland 's^ 1896, south of Iceland '3/^, — "9/^ 1896, 7/g 1896 and ^S;^ 1900,
south-east of Iceland "/,— '6/5 1895, ^°/c. 1896, north-east of Iceland 'o/^— ^s/- 1896, "ie—'^'e 1900 and
"ly 1901, south-east of the Faeroes 4/^. and '9^ 1895, 45—^/5 and '^/g 1896. The copepodites (\' — IV)
were practically found in samples from the same dates, the only interesting exception being their
occurrence at Disco Baj' 9/,^ 1892; the copepodites (III, II) were only found at very few stations, pro-
bably on account of their small size.

Distribution. The Pseudocalanus minuhis Kr. has its main distribution over the northern
part of the Atlantic Ocean, on the west side as far south as the Gulf of St. Laurence, and on the east
as far south as 35° Lat. North; it has been mentioned from the Black Sea, the Gulf of Suez and the
Mediterranean. In the Arctic Ocean it is known from Baffins Bay to the New Siberian Islands, and
has once been recorded from the west coast of North America (Puget Sound).

Far ran, mainly on material collected by the International Investigations, has given a fairly
exhaustive account of its distribution and the points of its biology. It is most often abundant in the
Baltic, except in the Gulf of Bothnia, in the Belts, Kattegat, Skagerak, along the coast of Norway,
in the English Channel, the Irish Sea and in coastal waters on the south and west coasts of Ireland.
"In the North Sea south of 55° it is always present but usually scarce, sometimes abundant". In the
north-west of Scotland, there is an indication of periodicity in its occurrence as well as of curious
variation from year to year; it was common in August 1903, moderate in August 1904 and 1906, scarce
in August 1907, and absent or almost absent in August 1905. In the Faeroe and the Fseroe-Iceland chan-
nel the recorded distribution is somewhat irregular; during several years it has been found fairly common
in May and August (in 1906 almost absent). "On the south and west coast of Iceland it is generally
distributed in the open sea ten miles or more from shore, but it is usually rare, and often absent from
the tow-nettings. In the coastal waters it may be found frequently, and often forms large shoals". On
the north coast of Iceland it has been recorded by Paulsen.

In the Norwegian Sea and southern Arctic Ocean between Jan Mayen and Iceland on the west
and Norway on the east it is in any case sometimes common or abundant

On the west coast of Greenland it has been recorded by Vanhoffen from Umanak Fjord
(1897) and rather abundantly from the surface down to 240 m. adults as well as copepodites b>-
Stephensen from Northern Stromfjord about 67°40 Lat. North (range of temperature 0° to 3-2^0.).

From the east coast of Greenland it has been recorded by CI eve 74°i5 Lat N. i8'i5 Long.
W. and by Koefoed, who has found specimens (1-42 to 17 mm. long) at 4 Stations between 78^09
and 77''35 Lat North, and i4°oi and i8°02 Long. West from the surface down to 65 met (Temperat.
-M"0 =-i7°C.), which he thinks ought to be referred to Ps. clongahis rather than to Ps. gracilis.

COPEPODA 65

As the Due d'Orleans is the expedition which has made the most systematic plancton-in-
vestigations from different depths with measurements of saHnity and temperature, and as Koefoed
and Dam as are the only ones, who have separated the three types, I think a more detailed survey
of their material, should pay.

Ps. major, which was first recorded by G. O. Sars north of the New Siberean Islands, was
only taken a single time 78°o5 Lat. N. 5°2i Long. W. '^7 1905 between 800 and 1350 met. (salinity
34'95°/oo; temp. o-o8° — -^o•37° Cels.).

Ps. clongatus was only taken near the coast of Spitzbergen (c. 80° Lat. North i4°33 Long. East)
at 4 stations near the surface (Temp. 0-50— 2-50° C.) and at the mentioned stations near East Greenland.

Ps. gracilis, which has previously been recorded by Sars at the coast of Finmarken and be-
tween Finmarken and Baren Island "a ete capture entre 600 metres et la surface; il est particuliere-
ment abondant au-dessus de 200 metres; d'apres les estimations faites par Koefoed, il parait nioins
frequent le long de la cote gronlandaise qu' an large, mais il est tres frequent tant dans le Gulfstream
que dans le courant polaire". The species is generally missing in hauls from 0—20 meters, but it has
been found common here at a few station (c) independent of the time of the day and of the temperature
(lying between -^ 170 and + 1-50). It has been found common at a depth between 480 and 600 metres,
juniores between 800—1000 metres (p. 270), and abundant at temperatures from -^ 170 to + 3° C. The
salinity, at which it is found common, varies from 30-60 °/oo to 34-90 %o-

As set forth by Far ran the conditions at which this species can flourish are very varied.
The salinity varies from 7-25 °/qo to 35-30 %o, the temperature from -f- 1-70° C. to 12-47° C, 't is found
from the surface near the coast, where it is often left in tidal pools, as deep as 600 metres in the
open ocean. About the details of its biology I refer to Farran, several interesting studies of Herd-
maun from the Irish Channel but especially to Kraeeft, who in the Baltic and the North Sea has
studied the growths and the occurrence at different depths of the various stages (juniores). He writes
(1910 p. 79) "es zeigt sich deutlich dasz das III Stadium von Schicht zu Schicht, von Boden nach der
Oberflache gerechnet in immer groszer werdenden Menge vorhanden ist"; he found that mature females
(April 1906 in the Baltic) were present in 59-1 % between 75 and 30 metres, but only in 3-1 % between
5 and o metres.

About the time of propagating I have in the literature only found that the Due d'Orleans has
collected mature females and males (8/7 1905 8o°i3 Lat. N. 7=42 Long. East 400-500 metres, 0-23—0-80° C,
and '5/8 1905 7i°22 Lat. N. i8°58 Long. East, 200—400 metres, 0-67—1-53° C).

Remarks. It has previously been mentioned that no characters are found by which all spec-
imens could be referred to one of the three types of Pseudocalaims viinuhis; in the same sample inter-
mediary links are found not only between the extremities of the mature females but also between
the copepodites of stage IV— V, in which however the difference between the types is less marked.
The question how to explain marked differences in size and other characters found in the same sample
under the same biological conditions, if they all belong to the same species, is too vexed to be ans-
wered now. Specificness of the different types may perhaps be excluded by the examination of several
hundreds of specimens at least, from samples with marked variation between the specimens, after
G a 1 1 o n ' s statistical methods.

The InjTolMIxpedition. III. 4. 9

66 COPEPODA

Some of the differences are certainly congenital, but others are probably due to the fact that
specimens, which later on are found under identical biological conditions, are born at different localities
and have got a different start in life, before being carried by currents or other agencies to their
present abode.

II. Microcalanus pygmaeus G. O. Sars.

1900. Pseudocalanus pygniEEUs n. sp. (9) G. O. Sars, pp. 73- 75 1907. Pscudocalanus pyginseus G. O. Sars. Dainas and Koefoed,

pi. XXI. pp. 396 and 407.

Spinocalaiius longicornis n. sp. (d") G. O. Sars, pp. 77 1908? Microcalanus sp. Farraii, p. 2S.

— 78, pi. XXII figs. 13 — 14. 1908. — pygnueus G.O. Sars. V. Bremen, p. 26 fig. 24.

1901. Pseudocalanus pygniajus G. O. Sars. Tli. & A. Scott, — pusillus G. O Sars. v. Bremen, ]>. 27 fig. 25.

p. 339. i 190S? ^ — — Wolfenden, pp. 41 — 42,

1902. — — — Mra7.ek,pp 508— : pi. 11 fig. 5.

509, taf. V figs 3 — II. 1908? — — — Hj. Brock.

1902? — — G. O. Sars. Giesbrecbt, p. 20, 1910? — — — Kraeeft, pp. 98— 99.

taf. 2. 1911 ? — — — Farran, pp. 98— 99.

1903. Microcalanus pygnireus G. O. Sars. G. O. Sars, p. 157. 191 1? — — — Wolfenden, p. 286.

? Microcalanus pusillus n. ,sp. G. O. Sars p. 156—157; sup- 1913. — pyguiffius G. O. Sars. Stephensen, pp. 311

plemcnt pi. II, pi. Ill fig. i. — 312.

Description, f $. Most of the examined fnll-grown females agreed fairly well with Sars' descrip-
tion of AI.pygvi(ri(s. The size of the specimens varied from 0-65 to 0-9 mm. In a single specimen (St. 8)
the antennnlae scarcel)- reached the end of the first abdominal somite, and the terminal spine of the second
pair of legs of this, as well as of other specimens, had indication of the serration which according to
Sars forms the chief characteristic between M. pygvicrus and ptisiUus\ as the natatory limbs were
broken in most of my specimens, I was unfortunately unable to examine this character in most .spec-
imens (cf. pag. 68). According to Sars the rostrum is represented by two "extremely small tentacular
filaments"; in my specimens, as in those examined by Mrazek and Kraeeft, these organs are
rather thick and more like teeth.

fc?. Size: i-i mm. The structure of the fifth pair of legs is very much like that figured by
Sars (PI. I pes V c?), but in my specimen the division of the left leg into 3 basal segments is more
indistinct.

Y (St. V). The juniores (c? — $ Copep. V) are practically like the preceding stage, but for the
number of abdominal somites. The male differs from the females by less prominent first abdominal
somite and a fairly well developed fifth pair of legs (cf. Mrazek fig. 13).

Y(St. IV): Size: ($) 0-65— 075; (c?) 0-65 — 0-9 mm. In this stage with only 3 abdominal somites
are the same differences between males and females observed.

Occurrence. Considering its minuteness one can not wonder that this species has only been
taken from the following few stations by the Ingolf Exp.
Davis Strait: St 29. 65°34 L. N. 54°3i L. W. 7? 3-30 p. ni. 1895. V. 50— o fm. Temp, at surface 3-5°

C. I?, ic?, 4y?(V), 8y<^(V).
West of Iceland: St. 95. 65°i4 L. N. 30°29 L. W. ^^/e 5"25 p.m. 1896. P. 100— ofm. Temp, at surface 7-8°

C. 16?, 5y?(V), 26ycr(V).
St. 8. 63°56 L.N. 24°4o L. W. 'Vs 5 P- m- 1895. V. 100- ofm. Temp, at surface 8-6°

C. I?.

COPEPODA 67

South-east of Iceland: St. 133. 63°i4 L. N. ii°24L. W. 9/g 96 1-30 p.m. P. 100— o fin. Temp, at surface

io-8° C. 2 ?, 2 yc? (V).
St. 58. 64°25L. N. i2°09L. W. ^% 96 3 p.m. P. 100— ofm. Temp, at surface
1-2° C. 7 ?, 2 y? iV), 2 y? (IV), 2 y^ |V), 2 yc? (IV), i y (III).
North-east of Iceland : St. 105. 65°34 h. N. 7°20 h. W. "/? 6-30 p. m. 96. Closing net. 700 fm. 11 ?, 2 yj* (V).

St. 104. 66°23lv. N. 7''25L. W. "/-j 5-30 a. m. Closing net. 850 fm. i ?.
Kast of the P'seroes: 6o°05 L. N. i°i8 L. E. 'Vs ii-45— 3-45 p. m. 96. Cyl. 46. i yd*.

West of the Faroes: 6o"'28 L. N. i2°ioIv. W. the East-Greenland Exp. has ^5/^ 1900 F. 397

taken 1 y c? (V).
The mentioned expedition has besides taken the species from the polar seas east of Greenland.
74°28 L. N. i5°3o L. W. ■% 1900 Closing net no— 40 fm. 2 y ? (V), 2 y? (IV), 2 y<? (V), 2 yc? ;IV).

72°02L,. N. 2i°2oL. W. '7? ^900 6 a.m. Closing net 35— lofm. i ?, i y$ (V), i y? (IV), 2 yc? (V),

2 yc? (IV).
Distribution. The Af. pygmccus G. O. S. was originally captured by Nans en (78° N. 13-6° E.)
in considerable numbers north of the New Siberian Islands in October 1893; by Bruce it was taken
at Novaya Zemlya "/e 1900 and by Schaudin at Spitsbergen 8i°32 L. N. The most important con-
tribution to its distribution in the polar seas and to its biology has been pubHshed by Damas and
Koefoed in the "Due d'Orleans". It has been taken at almost all the stations in the polar seas be-
tween Spitsbergen and Greenland as far east as io°42 Long. East and as far west as 18^22 Long. West,
as far north as 8o°i7 Lat. North and as far south as 75°35 Lat. North between ^^e and '^g 1905. The
authors write (p. 396) ^'•Microcalanus pygmcetis possede une grande amplitude verticale : il s'observe en-
core en abondance entre i-8oo et i-200 metres (St. 17) et ne manque dans aucun des echantillons pro-
fondes. II remont frequemment a la surface. Nos peclies prouvent que son niveau habituel est au
dessous de 100 metres". As all the information about each species, which is found under the gatherings
for each station, has not been collected for each species, I have tried to do it for Microcalanus pyg-
vicnis. Near the surface it has only been found: at St. 13 (0—20 metres, T. 0-30° C, Salin. 33^30 7oo, 7?
4-45 p. m.), at St. 30 (0-5 metres, T. 1-20° C, Sal. 31-32700 '7; S p. m.) and at St. 43 (0—20 met. T. 0-98°

=- 1-64° C. Sal. 32700 Vs 3 p- m.). As the salinity at which this species has been found lies between

31-10 7oo and 35 7oo the said authors may be right (p. 406) in referring it to the intermediary group of
species, which in the Norwegian Sea exceptionally are observed "a la surface surtout pendant la unit
et dans les eudroit-s, ou la salinite est elevee"; but their final statement, indicating a difference in the
vertical distribution in the different seas, about M. pygmaus (13.407) "a) Dans la Bassin polaire: con-
state a de faibles profundeurs. b) Dans la Mer du Gronland: principalement vers 100 metres; existe
depuis la surface jusque a 1850 metres, c) Dans la Mer de Norvege: sourtout aboudant entre 200 et
600 metres", is neither born out by their own material (tab. II) nor by the information available in
the literature. The species has not yet been recorded from the Norwegian Sea. The temperature, at
which this species has been found even in great numbers (cc) at different depths, varies from -=- 1-75
to -|~2-i5°C. ; it has been found fairly common (+) at 3-81° C, but its optimums temperature seems
to be a little below and a little above Zero. Adult males have been found at 11 stations in the Green-
land Sea between 's/^ and '78) "^ vertical hauls from 60 to 20 and from 1000 to 800 metres and at

9*

68

COPEPODA

a temperature between + 0*49° C. and -=- 175° C. In the literature I was unable to find any further in-
formation about this species, but about M. pusillus G. O. Sars, which possibly is identical with it, a
good deal of information is found. According to Far ran (1910 PP- 98^99) it has been recorded from
several of the Norwegian fjords at considerable depths, and from the sea between Jan Mayen and
Finmarken. According to Paulsen a species, which Sars has determined as AI. pusilbis, but which
really is AI. pygmceus (cf. later on), occurred plentifully in a depth between 230 and 350 metres on the
north coast of Iceland (M/g 1^04 66°20 L. N. i2°io L. W.). In addition it has been recorded from the
Irish Sea, the west coast of Ireland, the whole Norwegian Sea, the Skager Rak, the Kattegat and
in the extreme S. W. Baltic off Bornholm.

At Spitsbergen (8o°02 L. N. I7°02 L. E.) it was found l)y the "Due d'Orleans" in a depth of from
60— 30 ni. (Temp. 0-40— 027° C.) and by Hofsten and Bock (150 — 40 m. D.).

The Belgian Antarctic as well as the National Antarctic Expedition has in the Antarctic Seas
collected a good number of a minute species by nets let down through holes in the ice to a depth
of 200—500 met.; they have been mentioned by Giesbrecht and Wolfenden respectively as
AI. pygmcBus and pusillus. The latter has pointed out that Giesbrecht's description refers to AI. pu-
sillus (viz. comparatively short antennulae). Giesbrecht's localities lie between 7i°i8 and 69°48 Lat.
South and 92°22 and 8i°i9 L,ong. W. If this identification is right, the species should certainly be found
in the deep sea all over the world.

Remarks. I am fairly convinced, that the characters, which Sars has set forth to distinguish
Microcalaiius pygmwus and pusilbis viz: shape of St. pes IV and length of the antennulae are not
sufficient. In this point of view I have been even more convinced b\- examing some specimens from
the North of Iceland, placed at my disposal by the kindness of Dr. Paulsen and determined by
Professor Sars as AI. pusillus. Most of the specimens were young males with the antennulae reaching
about to the middle of the abdomen; the spinulation of the vSt. of the natatory legs was not very
coarse. In a single specimen (lengt 0-84 mm.) the vSt. j^es III has 16 dentations in proximal half in
contrast to Sars figure of AI. pusillus with 10 teeth, and to an adult female from Ingolf vSt. 8 witli
about 20. It seems evident to me that Paulsen's specimens ought to be referred to AI. fiygmcrtis, and
the fact that even such an authority as Sars has difficulty in distinguishing the two species from
each other, makes reservation necessary with regard to several identifications found in literature, and
bears out my doubts with regard to the validity of the two species.

The partial value of the two main characters have been mentioned. According to vSars the
size of the adult si^ecimens of AI. pusillus scarcely exceeds 07 mm.; several of ni}- specimens are
smaller. Mrazek, who has examined (^ and $, varying in size from 060 to 075 suggests the possibility
of referring them to two species, and Kraeeft points out minor differences between his specimens of
AI. pusillus and Sars' decription. It ma)' be admitted that a careful re-examination of a good material
from the different localities is necessary before settling the qustion of the identification of the species.

12. Clausocalanus arcuiformis Dana.

(PI. I figs. 9 a— d).

1849. Clausocalanus arcuiformis n. sp. Dana.
1892. — — Daua.Giesbrecht,pp. 1S5— 190,

taf. I, 2, 10 and 36.

1894. Clausocalanus arcuiformis Daua. Th. Scott, p. 73, pi. 8.

1895. — — — Giesbrecht p. 248.

COPEPODA

69

iSgS. Clausocalaiius arcuifonnis Dana Giesbrecht & vSchnieil,

p. 27.

1899.
1900.
1901.
1903-

1903-
1904.

1905-

1905.

Brad}', p. 32.
Wheeler, p. 171, fig. 9.
Clevc, p. 5.
J. C. Thompson & A.

Scott, p. 243.
Cleve, p. 359.
Cleve, p. 1 88.
Wolfenden, p. 999.
Esterly, p. 142, fig. 13.

1905. Clausocalanu.s arcuifonnis Dana G. O. Sars, p. 3.

1906.
igoS.
1 90S.
1909.
1909.
1910.
1910.
1911.
1912.
1912.

Pearson, p. 9.
V. Bremen, p. 23, fig. 20.
Farran, p. 28.
Pesta, p. 22.
A. Scott, p. 32.
Steuer, p. 22.
Farran, pp. 91—92.
Wolfenden, p. 203.
Pesta, pp. 20-21.
Sewell, p. 360.

Description. Between the specimen.s described by Giesbrecht and my specimens scarcely any
differences were fonnd. As far as the oral surroundings are concerned they scarcely show features of
greater interest. Just behind the rostrum a low epistoma bearing a few rather short and strong
bristles (fig. 9 a) is found. In tlie middle of the labriiiii proper a rather prominent, narrow and hairy
process is found, on each side of which a group of rather short setae is seen. Posteriorly the labrum
is on each side produced into a hairy wing-like rounded expansion. The oral surface of the labrum
(PI. I fig. 9 c) possesses on each side 3 — 4 longitudinal rows of short setae, and between these 3 trans-
verse groups, of which the posterior is the most developed.

The lamina labialis has three subdivisions. Orally and anteriorly two interiorly convex series
of hairs are observed on each side. The arrangement of the hairs behind the lamina labialis did not
show features of greater interest (1^1. I, fig. gd).

Occurrence. This species seems to be extremely rare within the area explored by the Ingolf
Kxpedition ; I have only examined 11 full-grown females and a single young one, which were taken
24/^ 1889 59" Lat. North and 17° Long. West.

Distribution. The species has previously been found on the west coast of Ireland '. In the
Mediterranean it has been recorded by several authors. In the northern as well as in the southern
parts of the Atlantic Seas it has been captured by the Monaco and the German Antarctic Expeditions.
On the west coast of South America it has been found as far south as 53° S. By Wolfenden it is
recorded from the Maladive Islands and from the Antarctic Seas as far south as Lat. 84°oi, and by
Brady from New Zealand (at the surface). In the Pacific Ocean it has been foinid between 20° Lat.
North and 26° Lat. South. Vertical range from the surface to 4000 met. Cleve has found the species
in the Arabian Sea (Temperat. between 24-8° and 267° C. and salinity between 36-20 and 3577 'Voo),
the Indian Ocean (7—4° Lat. North T. 277°— 29-35° C, Sal. 3084 -34-38 '^/oo) and in tlie Malay Archipe-
lago (T. 25-3° — 28-30° C. Sal. 32-22 — 33-80 "/oo). According to Scott (1909 p. 32) it is moderately common
over the whole area investigated by the Siboga Expedition.

Ice U a ^

13. Spinocalanus abyssalis Giesbrecht.
(Plate I fig.s. loa — b; textfigs. 15a — e).

1S88. Spinocalanus abyssalis u. sp. Giesbrecht.
1892. — — Giesbr. Giesbrecht, 1892 pp. 209

— 213, taf. 13 and 36.

1900. Spinocalanus longicornis n.sp. (9) G. O. Sars, pp. 75-78,

pi. XXII.

I According to Farran (1910 p. 92) "it is occasionally carried by currents into the mouths of the English Channel
and the British Channel, but has not yet been recorded from the west or north coast of Scotland". (Salinity 35 4°/ooj.

^o

COPEPODA

1902? Spinocalanus Schaudiniii n. sp. Mrazek, pp. 509 — 512, 1903. Spinocalauus abyssalis Giesbr. G. O. Sars, pp. 157 — 158;

taf. IV, taf. V fig. i. ' supplement pi. Ill fig. 2.

1903. — longicornis G. O. Sars. G. O. Sars, pp. 22 — 190S. — — — v. Bremen, pp. 28- 29, fig. 27.

23, pi. XII. 1908. — — — Farran, p. 27.

Description, f^. Size: varied from 173 to i-86 mm. Sars' specimens measured i-i— 1-6 and
Giesbrecht's I'l — 1'25 mm.

The specimens which I have examined are certainly to be referred to Gbt.'s species in spite
of minor differences, in which I most often agree witli Sars' description. The head and the first
thoracic segment are completely fused except in a single specimen, in which there was indication of
a subdivision. The fifth thoracic somite is, as seen in text-fig. 15 a, only indistinctly marked out in front.
The ventral protuberance of the genital somite is less prominent than figured by Giesbr edit, and
more prominent than drawn by Sars, and the shape is somewhat different.

a d

b c e

Text-fig. 15 Spinocalanus abyssalis Giesbr.

a. f?. Abdomen X 170. d. ycf (stage V|. Abdomen X 170-

b. fcf. Lateral thoracic comer X I7C'- e. yd' (stage V). Pes V X c. 225.

c. fcf. Pes V in anterior \-iew X 225.

The oral appendages are scarcely different from Giesbrecht's description. In the structure
of the natatory legs a few differences are observed. The nimiber of bristles which are present on the
anterior surface of the second basipodite are fewer in number than figured by Giesbr edit. The exte-
rior seta of the first outer segment of the first pair of legs is distinctly more slender than that of the
following segments. The number and the arrangement of the spines or setae which adorn the surface
of the exopodites and endopodites in the last three pair of legs show variations from specimen to
specimen, and are not quite like Giesbrecht's description; in most specimens f. inst. short sj^ines
are observed, as figured by Sars (PI. XII), not only on the posterior, but also on the anterior surface
of the two last segments of the endopodites. In the second pair of legs the usual glandular pores were
observed at the base of the exterior seta in the two last segments; none was observed in the basal
segment.

The labrum proper is less prominent than figured by Sars (PI. Ill 2c). In front of the hinder
margin in the middle a transverse row of long bristles is observed, but here none along the margin

COPEPODA 71

proper; laterally a series of short setae is observed (PI. I fig. 10 a), and in front of these, partly on the
oral snrface, a gronp of short spines or grannies is observed. Orally we find on each side an inner and
an onter series of delicate bristles, arranged in a short posterior and a long anterior division. As far
as the strnctnre of the labinni etc. is concerned I refer to the fig. 10 b.

fc?. Size of male 1-63 mm.

Tlie thoracic somite IV and V are as seen in the text-fig. 15 b well separated. Tht antennulae
have the articnlar-membranes between the segments Stvg and 10, 10 and 11, 11 and 12 rather in-
distinct; the antennnlae become rather snddenly narrower beyond segment 14, which is wider than
15. The first to ninth segments possess two bristles in addition to one or two "Aesthetasken"; in the
following segments, except in the 12th, no distinct proximal seta (Spr.) is observed, bnt small incisions,
corresponding to their insertions; "Aesthetasken" are observed in several of the segments. The oral
appendages are as shown and partly figured by Sars rather rudimentary. The viaxillulae show the
following features. The Le possesses 7 short bristles; the Li I has only a few rudimentary setae, and
the rather prominent L,i II — III have 3 short delicate bristles each. The Basp. has 5 and the Ri I — III
4 -j- 4 -f 6 bristles, of which those of Ri III are fairly long and slender. The Rehears 11 partly power-
ful hairs. The viandiblcs are figured by Sars; the anfennac^ the viaxillae and the maxillipeds are
less powerful, bnt in the main features alike those of the female. The lahnuii and labial appendages
show exteriorly a structure scarcely different from that of the female.

The Se of Re I pes I is even less developed than in the female. The structure of the fifth
pair of legs (cf. text-fig. 15 c) is in some points different from Sars' description; between the Re I and
II on the right side an indistinct limitation is seen.

Y (St. V). Size: 1-45 mm.; anterior division i-oo and the abdomen 0-45 mm.

The shape of the body is scarcely different from that of the female; there is indication of
articulation between the head and first thoracic somite; the two last thoracic somites are, as seen in
text-fig. 15 d, well developed. The oral and natatory appendages are scarcely different from those of
the females. The structure of pes V is shown in text-fig. 14 e.

Occurrence. The Ingolf Expedition has taken 2 mature females, a single mature male and
two young ones (St. V) 2% 1895 2 p. m. V. 200-0 fathoms St. 25 63030 Lat. N. 54°25 Long. W.

Distribution. This species has been taken at 2 different stations in the polar seas in about the
80th degree of latitude and the 134th degree of longitude east as well as at 8i°32 L. N. by Romer
and Schaudinn, on the coast of Norway (Osterfjord Norway in the depth from 400 -boo metres),
and in moderate numbers on the west coast of Ireland "at all depths from 200 to 1000 fathoms". Ac-
cording to Giesbrecht it is found "99°— 132° W. 3° S.— 14° N. In 1000—4000 Meter Tiefe".

Remarks. The female described by Mrazek as Spinocalanus Schmidinni \s certainly identical
with the mentioned Species. His male, however, seems in rather important features to differ; in his spec-
imen the segments VIII to XIV of the antennnlae are completely fused (Taf. V fig. i), and the pes V
differs distinctly, especially by the Ri, the terminal seta of which just reaches beyond the end of Re I.

72

COPEPODA

14. Spinocalanus magnus Wolf.

1904. Spinocalanus magnus n. sp. Wolfenden, p. 118. 1 190S. Spinocalanus magnus Wolf. Farran, p. 27.

1905. — — Wolf. Farran, pp. 30—31, pi. IV 190S. — — — v. Bremen, p. 29, fig. 29.

figs. I — 12.

1906. — — — Pearson, pp. 10— 11.

1907. — — — Damas & Koefoed, p. 409.

1911? — — — Wolfenden, pp. 216-217,

text-f. S, pi. XXV figs. 3—5.

Description, f?. Size of female from Thor St. 82 2*8 mm.; anterior division measured 2"2; nro-
some 0-6 mm. Wolfenden's specimens measured 275 and Farran's 2-9 mm.

As far as could be made oiit by the examination of the two very mutilated specimens, they
do not seem to differ in any feature of interest from Farran's description.

In the second pair of legs no glandular pores were observed in the first outer segment, but a
distinct one in the second segment, and three near the base of Se in the third outer segment.

In front of the labrum proper, which is very prominent, a smoothly rounded elevation was
found; the structure of the labrum etc. was not examined in detail.

Occurrence. Of this species I have only examined two mutilated females, gathered by the
Thor M/(, 1905 St. 82 5i°oo L. N. 11^43 L. W. Yt. 1200 M. Wire.

Distribution. This species is according to Farran of frequent occurrence on the west coast
of Ireland "from the surface to i-ooo fathoms, though never very plentiful". According to Koefoed
& Damas it is found "dans la raer dn Gronland: de 800 a an moins i-8oo metres". According to the
tables prepared by Koefoed, it has been found at four stations, but according to the records from
each single station it has only been found at St. 22 79° L. N. i°52 h. E. 800—1350 metres and at St. 48
71° L. N. i8°58 L,. W. 800—1000 metres. The .species is by Wolfenden recorded from the Antarctic,
but he is probably not right in referring the Antarctic animals to the northern species, as his figure
shows the genital somite less distinctly produced.

Aetideidae G. O. Sars.

Little by little a good manj- genera of the Aetideidae hav'e been established; these genera are not
at all of equal value, and in their definition not the same principles have been followed. M)- material
has not been sufficienth' exhaustive for a final solution of the question, but nevertheless a few remarks
upon the value and the position of the genera, which I have examined, may be useful.

As a whole I think that undue stress has been placed on the presence or absence of the
lanielli-formed setae or spines along the inner margin of second basipodite in the fourth pair of legs.
Cliiridius and Aefidiopsis are the only genera in which marginal setae of usual structure without
spines are found; in Aetidius (PI. II fig. ic) terminally and posteriorly a few teeth were found in
addition to the usual slender setae. In most species of Gaiditis, Gaetamis and Eucliirella the setae are
transformed into more or less well developed spines. In Underchate minor and nearly related species
the margin is either completely smooth or possessses a few terminal teeth (cf. text-figure) and in Chiru-
dina^ the margin is either completely smooth as in Cli. Streetsi, or possesses well developed spines

COPEPODA 73

(C/i. abyssal/s and pustulifera). Corresponding to the difference between the mature females and males
a difference is sometimes found between the two sexes in the penultimate stage; in Gaidius temiispi-
iiiis and Euchirclla rostrata f. inst. the young female has along the inner margin of the second basi-
podite in the fourth pair of legs a few lamellous setae, while the young male has a few of usual
structure; in most species of Eiicliirilla and Chintdiiia the margin is smooth in both sexes in the
penultimate stage.

The Actidius is a well characterized genus which, as far as can be concluded from the wanting
glandular pore in Re I pes II and the well developed marginal setae in the fourth pair of legs, is a
rather primitive form. The Chiridms, to which genus I refer not only Ch. obtusifrons without distinct
rostrum, but also Ch. ari/iatiis in .similarity to vSars and in contrast to Vanhoffen and Wolfenden,
is among other features characterized by the wanting plate-shaped process of the second basipodite of
the maxillipeds, the well developed exopodite of the first pair of legs with 3 setae, and the slender
marginal setae of the fourth pair of legs; as Giesbrecht had originally established the genus for a
species without rostrum, Wolfenden and Vanhoffen have accepted the name Pseudoactiduis for
Ch. ar Hiatus \ Sars has judged this single character as being of minor importance, and he is certainly
right, especially when it is taken into consideration that a rudimentary slightly bifurcate rostrum is really
found. On account of the great number of glandular pores in the three last pair of legs (PI. II figs.
3 — 5a) I once thought that Wolfenden was right; but as Ch. viodcstus n. sp., which in other respects
was like 67/. aniiatns, has 3 glandular pores (including one in Re I), I definitively accepted Sars'
definition. Sars has established a new genus JEtidiopsis synonymous with Wolfe n dens FaerocUa,
especially characterized by well developed fifth thoracic tergite; as a fairly well marked fifth somite
is found in most specimens of Ch. armalns.^ I do not think this genus is a good one. A.Scott's new
genus Gaidiopsis (1909 p. 52), characterized by a very robust rostrum, is probably nearly related to
Chiridius.

The genera Bradyetes Farr. and Undinopsis G. O. Sars (synonymous with Brady idius Giesbr.)
are nearly related; Pscudoeuchmte Sars is according to Far ran related to these genera as well as to
Bryaxis Boeck, the position of which seems to be a little doubtful on account of the poorly developed
outer ramus of the antennae. The position of Sars' genus Chiridiella is very doubtful. I have not
had the opportunity of examining any specimens of the last mentioned five genera.

According to Giesbrecht (1892 p. 249) the genus Gaidius has "rostrum kurz einspitzig"
and "Aussenast des ersten Fusses zwei . . . und Innenast des i. und 2. Fusses eingliedrig" and the only
difference from Gactauus is found in the frontal spine and the two-segmented endopodite of the second
pair of legs of the latter genus. The character found in the segmentation of the endopodite
of the second pair of legs is not of much value, as this articulation is well developed in
most species of Gaetanus as well as in Gardius brevispifitcs^ slightly developed in Gaeianus miles and
Gardtus tenuispinus, and completely wanting in Gaetanus minor. The presence or absence of the frontal
spine seems to me to furnish a good specific, but scarcely a generic, character; Sars seems to share
this opinion, as he has established a Gaetanus inermis ^'\ihQvX z.\\y si^\\\&. Wolfenden has established
a new genus Mesogaidius (191 1 p. 223) for his AI. intermedius, perhaps identical with G. brevispinus, and
his M. maximiis, because they combine the wanting frontal spine with "das Vorhandensein eines Zipfel

The Ingolf-ExpcJition. III. 4. jq

74 COPEPODA

am Aussenaste der hiiitereii Autennen iind eiiier eigentunilichen Cliitinlamelle am Rande der hinteren
Maxillipeden". The former character is found in G. tcmiispinus as well (PI. Ill fig. 2 1)), and the latter
is scarcelj' sufficient; the exopodite of the first pair of legs of M. maximus has 3 distinct seg^ments,
each with a well developed outer seta, a character not found in any Gaidiiis or Gactamcs known to
me. If we regard the following species of Gaidiiis and Gacfanus as forming one group, the natural
division will probably be the following: i) the Gardius toiuispiiiits which has no frontal spine and
no lamina in the second basipodite of the maxillipeds; the second segment of the exopodite of the
antennae possesses a distinct process for the second seta, the first segment of the exopodite in the
second pair of legs has no glandular pore, and the inner margin of the second basipodite in the fourth
pair of legs in the young females has a few stiff setae, while in the young males it has a few
of usual structure, 2) the Gaidius brevispimis which has a well developed lamina in the maxillipeds
of the female, and the male of which has not a minute outer seta in the second segment of the
exopodite in the second pair of legs, 3) the Gaetanus Kruppi and lafi/'rons, which differ from the two
preceding species by the frontal spine, and the presence of ten instead of eleven setae in the exopodite
of the maxillulae, but in other respects, except the lamina of the maxillipeds, agree with G. fcnuispinus
4) Gaetanus minor which, except for the wanting glandular pore in the first outer segment in the second
foot, completely agrees with the preceeding group; and 5) Gaetanus pileatus and miles^ which in ad-
dition to the wanting glandular pore of the second foot do not possess any process in the second
outer segment of the antennae, and have the inner margin of the second basipodite in the fourth foot
smooth in both sexes in the penultimate stage. For settling definitively the question of the relative
position of the species, the structure of the fifth foot in the male of G. miles must be known. At
present I am inclined to regard Gaidius /enuispimts and Gaetanus Kruppi as being more nearly related
to each other than the latter species is to Gaetanus miles. In addition to the mentioned characters all
the enumerated species have the lamina labialis rather simple, without the division in three portions
as in Euchirella, in contrast to Chiridius and Aeiidius. The position of Chirtidina, to which not only
Cli. Streetsi but also pusttUi/era, adyssalis, notaeant/ia, parvispina and spcctabilis are referred, is a little
doubtful. These species are in several respects rather different, but show their affinity by the structure
of the oral surface of the labrum, and the structure of the fifth pair of legs in the male; the second
outer segment of the antennae have distinct setigerous processes, the outer surface of the maxillae
(PI. V figs. 5 c) is not very produced, the maxillipeds have a rather characteristic structure, the exo-
podite of the first foot is more or less distinctly three-divided, with three outer setae, and the glandular
pore of the first outer segment is wanting in the second foot; the inner margin of the second basi-
podite in the fourth pair of legs is either more or less smooth, or has a distinct corona of spines in
tlie mature female, but is completely smooth in both legs in the penultimate stages. Some of these
characters suggest affinity to Chiridius.^ others to Gaidius\ if Wolf end en's Mesogaidius maximus
with a lamina in the maxillipeds, and the outer edged spines in the second pair of legs, really belongs
to this genus, a connecting link with Gaidius is found. The three last species ought perhaps, on ac-
count of the structure of the fifth pair of legs, to form an independent genus, and others, f. inst. Ch. pus-
tuli/era., ought perhaps, as suggested by Sar s, to be referred to Undcnchcete, the most nearly related genus.
As, how-ever, the three or five species which I have referred to this genus form a w^ell defined group,

COPEPODA

75

I have preferred to exchide other species of somewhat doubtful position, as well as to let Wolf-
enden's genus Mesimdeuchcrta go out. Though the different species of EuchireLla differ from
each other in several important features, I think the genus is a quite natural one, as it is not only
characterized by the structure of the antennae and maxillulae, but also by the presence of a glandular
pore at the base of Se I Re II pes II— IV (cf. Chiridms], which is wanting in the penultimate stage.
In Euch. rostrata, mcssmensis^ maxima and betumida a glandular pore is wanting in the first outer
segment in the second pair of legs, but in E. curticauda and intermedia it is wanting in the third
and fourth pairs of legs as well. In addition to the generally accepted specific characters, good ones
are found in the structure of the oral surface of the labrum, in the number of bristles of the exopodite
of the maxillulae in the males, and in the marginal hairs of the second basipodite of the fourth
pair of legs.

15. Aetidius armatus Boeck.
(PI. II fig. I a-d; text-fig. 16).

1S72. Pseudocalanus armatus n. sp. Boeck, p. 38.

1SS3? Aetidius armatus n. sp. Brady, p. 75.

1892. nee. —

1S93. pars. —

189S. pars. —

1901. —

1902. —

1902. —

1903. —
1903. —

1903? —

Brady. Giesbrecht, p. 213, taf. 2, 14
and 36.

— Th. Scott, p. 70.

— Giesbrecht & Schnieil, p. 31.
Boeck. Th. Scott, p. 23S.

-- Th. Scott, p. 451.

— G. O. Sars, pp. 25 — 26, pis

XIII— XIV.

— Norman, p. 136.

— Jensen, Johansen, Levinsen,

P- 304-
Brady. J. C. Thompson, p. 16.

1904. Aetidius tenuirostris n. sp. Wolfendeu, pp. 116 — 117

1905-

—

armatus

Boeck.

Farran, p. 31.

1905-

—

—

—

Esterly, p. 145, figs. 14 a — b.

1905.

—

—

—

Th. Scott, p. 222.

1906.

—

—

—

Pearson, p. 11.

1908.

-

—

—

V. Bremen, p. 30 fig. 30.

1908.

—

—

—

Farran, p. 28.

1909?

-

—

—

Pesta, p. 23.

1909.

"

A. Scott, pp. 37 - 38, pi. IV, figs
14-25.

I9I0.

—

—

—

Steuer, pp. 23—24.

I9I0.

—

—

—

Wolfenden, p. 209, text-fig. 4.

I9II.

—

—

—

Farran, pp. 81 — 82.

som.

Description. % Size of specimen from Ingolf St. 47, i'93 mm.: anterior division (head
thor. I 0-920; somite II — V 0-575) 1-495; "I'osome 0-437 "i'"-

The head is as figured by Sars etc. vaulted in a characteristic way without frontal keel, and
the rostrum has two pointed branches without basal tubercle. The genital somite, which is both wider
and deeper than long, has a receptaculum seminis (text-fig. 16) which is distinctly dif-
ferent from that of A. Gicsbrcchtii CI eve 1904 (synonymous with A. vieditcrranctis
Steuer 1910), as seen by comparing figs la — b with Giesbrechts fig. 9 Taf. 36; the
vulva (fig. lb) is also somewhat different from Giesbrecht's fig. 8.

The measurements of the antennulae are distinctly different from those given
by Giesbrecht, as the segment 23 is shorter than 22, and as segment 24^^25 is
respectively 1-4 and 1-5 as long as segment 8039 and 2 (not 2 and 2-5). The antennae
differ from Sars' as well as from Gi esbrecht's figures by the sinall process on which
the proximal seta of Re II is placed. The other mouth appandages show some dif-
ferences from Sars' figures, but not in any feature worth to be mentioned from Gies-
brecht's description.

The pes I differs from Giesbrecht's description (fig. 10) by the second basipodite, which has
no setae exteriorly and distally, and by the third one, which has no spinous area laterally and anteriorly.

Text-fig. 16.
Aetidius armatjis

Boeck.
Abdomen in left

view X 57.

COPEPODA

The pes II has the articular membrane between Re I and II distinct anteriorly, but missing posteriorly;
the hasp. II pes IV has, in addition to marginal row of setae, posteriorly and just proximally to the Si a
transverse row of 4 short spines (PI. II fig. i c), which corresponds to the two spines mentioned by
Giesbrecht but not by Sars and Scott Glandular pores were found at the base of Se Re II and
Se 3 Re III in the three posterior pair of legs, and in addition to these a pore was found at the base
of Se Re I in pes III-IV.

The labrum is in lateral view like Sars' figure, with a short anterior elevation, which by a
low incision is separated froui the labrum proper; this is, anteriorly, evenly convex and, posteriorly
towards the free margin, slightly concave. In front of the marginal row of setae along the free poste-
rior margin no setae were found. The oral surface of the labrum is most like that of Gaicluis\ the
longitudinal group i consists of a single series of fairly long hairs; the groups 2 — 5 are only in-
distinctly separated, and only the groups 4 — 5 are 2—3 setae. deep. The lamina labialis and the setae
in front of it have a structure as shown in figure i d.

Y? (V). Size of specimen from St. 45 1-58 mm., anterior division 1-23 mm.; urosome 035 mm.

This stage differs distinctly from that of the adult female by the structure of the abdomen.
The head is well separated from the first thoracic tergite, and the fifth from the fourth; the appendages
do not show any difference of importance, except the even less developed articulation between Ri I — II
pes II, and the wanting spines in besipodite II pes IV, which has however the usual marginal setae.

Occurrence. The Ingolf Expedition has gathered this species at the following stations viz:

V7 1895 St. 27 64°54L. N. 55°ioL. W. V. 200—0 fm. Temp, at surface 3-9° C. i f?.

26/6 1895 St. 25 63°30 Iv. N. 54°25 L. W. V". 200-0 fm. 2-9° C. if?.

3% 1895 St. 38 59°i2 L. N. 5i°o6 L. W. V. 100— o fm. 10° C. i f ?.

■8/61895 St. 19 6o°29 Iv. N. 34°i4 L. W. V''. 300-0 fm. 9° C. 6 f?.

27,1895 St. II 64°34 L. N. 3i°i2 L. W. V. 200— o fm. 8-2° C. if?.

'Vs 1896 St. 47 6i°32 L. N. i3°4o L. W. V. loc^-o fm. 10° C. 15 f?.

•■Vs 1896 St. 52 63°57 L. N. i3°32 L. W. V. 200 --o fm. 8-3° C. if?.

2% 1896 St. 57 63°37 L. N. i3°03 L. W. V'. 100— o fm. 8-2° C. 11 f?.

2% 1896 St. 59 65° L.N. ii"i6Iv. W. Apst. 12 1-5° C. if?,

"/s 1896 St. 45 6i°32 L. N. 9°43L. W. V. 100— o fm. 9-1" C. 2f?, iy?(V).

In addition to these Captain Wan del has 1891 at 67°07 L. N. ii°4i L. W. taken i f?, and the
Danish East Greenland Expedit. 1900 10 p. m. F. 403 has gathered a single female 6o°29 L. N.
i2°io L. W.

Distribution. This species is according to Far ran "a characteristic inhabitant of the lower
layers of the North-East Atlantic off the coast of Ireland and Scotland": It has been found in the cold
as well as in the warm area of the Faeroe channel, the northern part of the North Sea, and several
of the Norwegian fjords. It has been taken off the Finmark coast N. W. of Nordkyn and north of
Iceland. The records of the Ingolf. Exp. show that it is also found in deep waters, probably as a
member of the Atlantic fauna, in the Iceland-Fseroe channel, Denmark and Davis Straits. This
species seems to have a very wide distribution; according to Scott and Wolfenden the spec-

COPEPODA

77

inieiis which they have referred to A. armafus are not to be distinguished from specimens from the
northern seas. The gulf of Guinea, the South Atlantic, the Indian and Malayan Seas ought accor-
dingly to be regarded as lying within the range of this species. Even if Sars is right, that some
of Brady's specimens are identical with Boeck's species, we are not right in concluding that the
species has the distribution stated by Brady (cf. A. Scott's remark p. 37).

16. Chiridius armatus Boeck.
(PL II figs. 3a— e; text-figs. 17 a— d).

1872. Euchate arniata n. sp. Boeck, p. 39.

1S97. nee. Pseudocalanus armatus Boeck. Vanhoffen, p. 279,

fig. 16.
1900. nee. Cliiridius armatus Boeck. G. O. Sars, pp. 29—30.
1903. — — — G. O. Sars, pp. 27 — 29,

pis. XV -XVI.

1903. — — — Jensen, Johansen & Le-

viusen, p. 304.

1904. Pseudoaetiflius armatus Boeck. Wolfendeu, pp.115

and 131, pi. IV figs. 29—31.

1905. Chiridius armatus Boeck. Farran, p. 34.
1905. — — — G. O. Sars, p. 2.

1905. — — — Th. Scott, p. 222.

1906. Pseudoaetidius annatus Boeck. Pearson, p. 11.

1907. Chiridius armatus Boeck. Koefoed & Damas, p. 408.

1908. — — — Farran, p. 30.

1908. Pseudoaetidius armatus Boeck. v. Bremen, p. 33,

fig- 34-

1911. Chiridius armatus Boeck. Farran, pp. 90 — 91.
1913. nee — — — Stephensen, p. 316.

Description. f$. Size of specimens from Thor St. 172 measured 4-43 mm., anterior division
3-3 mm., urosome i-io mm. The smallest specimen (Thor St. 72) measured 3-6 mm.

The body diff erred in the following features from Sars' description; laterally and beneath, the
limitation between the head and first thoracic tergite is indicated; the fifth thoracic tergite, which is
produced into well developed triangular points, is ^ b e

short, but well distinguished (text-fig. 17 c). The
genital somite is only slightly produced beneath, and
the receptaculum has, as seen in fig. 17 d, a charac-
teristic structrtre. The furcal rami, which are a little
longer than the anal somite, are scarcely 1-3 as long
as wide.

The cnitcnmilac, which have the segment 25
well marked out with rather indistinct articular
membrane, have the segment 2 a little longer than

8 IN) 9, which is as long as the segment 20; the seg-
ment 21 is a little longer than 18, and the segment
23 is distinctly it as long as 24. The arrangement
of the appendages is scarcely different from that of Cli.

obtiisi/rons ; the posterior seta of the segment 23 just Text-fig. 17. ChfriJius armaUis Boeck

a. Head in dorsal view X i6- b- Head in lateral view X 60.
reaches the tip of the segment 25. The exopodite c. First abdominal somite in dorsal view X 50-

r , , . , , ,, 1 d. Lateral corner etc. X 60. e. Parasite attached to the

of the mitcnnac is scarcely 1-4 as long as the endo- ^^^^^ maxilla x

podite. The Le i of the maxillulac has as usual

9 setae and the Li 2 possess 5 spinelike setae, the Li 3, which terminally on the anterior surface has a
curved row of short spines, has 4 setae, and the basipodite III has a similar row of short spines and

78

COPEPODA

5 setae. The Ri has 13 setae as the Ri I has 3 vSa + i Sp, and the Re has only 10 setae. The
posterior seta of the first lobe of the viaxilla is at least 3 times as long as the lobe itself. In the
maxillipeds the third basipodite is about 1-3 as long as the second, and three times as long as the endo-
podite. The fourth lobe possesses in addition to the usual 3 hairs a short hairy sensory process. In
contrast to Sars' figure the distance between the Si 2 and Si 3 is 2-5 as long as the distance between
the Si I and 2.

The Jirst pair of legs has the Se Re I just extending beyond the tip of Re II. On the
anterior surface of Re II, near the lateral margin, i — 2 minute pores are often observed, and at the
outer margin of Re III, somewhat posteriorly, just in the middle, a pore, placed on a minute process
surrounded by delicate hairs, is found. The pes II has a fairly distinct articular surface between
Re I— II anteriorly, but posteriorly it is partly wanting in contrast to pes III— IV, in which it is well
developed. The terminal spine has 40—50 well separated teeth (fig. 3 a). On the anterior surface of
the Ri III the usual glandular pore surrounded by delicate hairs is found in the last three pair of
legs; the usual glandular pores at the base of Se Re I— III in the three la.st pair of legs are not seen,
but they are certainly represented by a uumber of pores which, as shown in fig. 3 a, in the arrange-
ment provides an important character for this species; the "pore" is formed by a chitinous ring, in
the middle of which a generally longitudinal split is seen. In the Re I a single pore and in Re III
three are found in pes II — IV, but in Re II a single is found in pes IV, but 2 in pes II— III.

The lateral outline of the labrnvi is like Sars' figure PI. XV, and scarcely different from
Aetidius. The anterior surface of the labrum has, in addition to the usual marginal row of setae
which are fairly slender in the middle and more like granules laterally, in the middle a transverse
row of laterally shorter setae, and in front on each side a group of short setae.

The oral surface of the labnini is rather characteristic (fig. 3 b). In front of the chitinous
transverse bar behind the median central spot Nr. 3, a transverse row of short setae is found; around
and behind the median spot 4 (S4) short setae are placed in transverse rows. The skin is everywhere,
especially posteriorly, minutely granular. The lateral longitudinal series consists as usual of 5 groups;
the two first groups are placed somewhat longitudinally, are distinctly longer than wide, and consist
of .short spinules, most like granules; the groups 3 — 5 are, in contrast to the two first, less well sepa-
rated, and consist of an inner row of longer and an irregular, outer group of scattered shorter hairs.

The lamina labialis (fig. 3 c) is in the shape of the dentations somewhat different from that of
Ch. obfusifrons (fig. 2 a), and it is almost smooth. The arrangement of the groups of hairs in front of
and behind the lamina labialis I refer to Cli. obtusifrons. About the arrangement of the series of
bristles on the labial lobes, the fig. 3 d will give an impression.

fd*. Size: Specimen from Thor St. 99 1904 measured 366 mm., anterior division 2-65 mm.
urosome foi mm.

The body seems to be more slender than figured by Sars; the anterior division is 2-6 as long
as the urosome; the fifth thoracic tergite is well distinguished. The first abdominal somite is some-
what assymmetric, and the genital pore is found on the left side; the second somite is three times
as long as the first; the f ureal branches, which are almost twice as long as the anal somite, are i-6
as long as wide.

COPEPODA

79

The Aiitciniulac are in the main Hke Sars' figure; the segments 24^^25 are ahiiost completely
fiised; the segments 8oog and 10 as well as the 20 — 21 are almost completely fused on the right side,
but fairly well distinguished on the left side. The segments 8^9 are a little longer than 2, which is
about 1-2 as long as segment 20; the posterior seta of segment 23 is very short. The aiifoiiiac are
scarcely different from those of the female, in contrast to the mandibulae which, except for the presence
of 2 instead of a single seta in Ri, are completely like Sars' figure without distinct manducatory plate.
The manducatory part of the inaxillulac is scarcely developed, and the rudimentary Li I bears a few
short sensory appendages instead of spines; the Li 2 is not developed; the Li 3 bears 2 feathery
bristles, the basipodite 3, and the eudopodite 9 setae; the exopodite possesses 9 strong plumous setae.
The inaxillac are comparatively more slender than figured by .Sars, with a number of very short
spinules and three proximal knobs. The inaxillipcds differ from those of the females by the com-
paratively long Ba.sp. Ill, which is 17 as long as the second. The first four pair of legs is scarcely
different from those of the females. Pes V is scarcely different from Sars' description; the Ri sin
(fig. 3 e) is rather elongate; about the structure of the right and the left exopodite I refer to figs 3g — f.

Y (Stage V). Size: vSpecinien from Thor vSt. 72 measured 3-05; anterior division 24 mm.,
urosome 0'65 mm. Another specimen was 365 mm.

The abdomen consists as usual of four somites, of which the second is the longest; the
antennulae are comj^aratively longer than in the females, and reach to aboiU the end of the second
abdominal somite; the articular membrane between the Ri I — II pes II is only indicated by a faint
line. The pes V of the male is, as shown in PI. II fig. 3 h, like that of Gaidius.

Yd* (Stage IV). Size: Specimen from Thor St. 82 measured 2'i6 mm.; anterior division 17 mm.;
urosome 0-46.

The shape of the bods- is like that of the adult specimens, but the abdomen has only three
somites; the number of segments is somewhat reduced in pes IV, as Re II -^^ III and Ri II ~ III are
mor a less completely fused. Two glandular pores were observed in Re III and one in Re I. The
pes V is rather rudimentary, as seen in fig. 3 i.

Variation. In a few specimens from Thor St. 172 % 1905, which, except for the less promi-
nent sexual area, were in all other respects like the adult females, a fifth pair of leg.s, as shown in
fig. 3J, with the right leg the longer, was found. In a specimen from St. 72 (Thor 1905) the left leg
was longer and more slender (fig. 3 1), and in one from St. J73 (Thor 7/g 1905) fig. 3 k the right leg
was again the longer. In two specimens from vSt. 104 (Thor ^4/^ 1904), and in one from St. 99 (Thor
^^/s 1904), the pes V was like fig. 3 e; the last mentioned specimens as well as one from St. 153 (7/9
1905) with pes V dext. > sin. and well developed eggs had the genital somite of female type, but without
distinct receptaculum seminis.

As most of the mentioned specimens were in all respects but the presence of pes V like the
typical ones, and as the mentioned stucture was variable to a degree, it must be regarded as a kind
of abnormity (cf. similar structures in Pseudocalanus).

Parasites. In a single adult female from Thor '/, St. 285 a stalked parasite was found, attached
to the first basipodite laterally on the anterior surface of the right maxilla; the body consisted of

So COPEPODA

-fc

a chitinoiis wall and a granular content, and was as a whole not quite unlike a spermatophor.
(text-fig. 17 e).

Occurrence. Of this species the Ingolf Expedition has taken a single adult female ^% 1896
St. 92 64°44 L. N. 32"52 L. W.

The Thor Expedition has gathered the species, fairly connnou, at several stations, most often
in deep hauls.

Thor 'V? 1904- St. 153. 65=20 L. N. 27°i2-5 L. W. Yt. 800 M. Wire i f?; i fc?; i yc? (V).

9/7 1904. St. 178. 63°o8 L. N. 21^30 h.W. Yt. 750 M. Wire i f$.

Vq 1904. St. 285. 62°49 L. N. i8°46 L. W. Yt. 500 M. Wire 17 f?.

"/7 1904. St. 183. 6t°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 15 f?; 2 i<^\ 2 Vc? (V).

^4/5 1904. St. 104. 62''47 L. N. i5°03 L. W. Yt. 1500 M. Wire 8 f?; i yd" (V).

,29/81905. St. 164. 6i°20 L. N. ii°oo L. W. Yt. 300 M. Wire 2 f?.

"/s 1904. St. 99. 6i°i5 L. N. 9°35 L. W. Yt. 1700 M. Wire 2 f?; 2 fd".

Yt. 900 M. Wire 3 f ?.

"/s 1904. St. 78. 6i°o8 L. N. 9"28 L. W. 5 f?.

23/7 1905. St. 124. 61 "04 L. N. 4'33 L. W. Yt. 100 M. Wire i f?.

Outside the Ingolf area the S/S. Thor has gathered the species at the following stations.

Thor "S/e 1905. St. 82. 5i''oo L. N. ii'=43 L. W. Yt. 1200 M. Wire i f?; i y? (V).

800 M. Wire 2 f?; i yj" (V); i yc? (IV).
2% 1905. St. 88. 48 'oo L. N. 8°3o L. W. Yt. 300 M. Wire 4 f?; i y? (V); 2 yc? (V).
76 1905. St. 72. 57°52 ly. N. 9°53 L. W. Yt. 1500 W. Wire 75 f $ (one with spermatophor)

ifc^; 4yc?(V); iy?(V).
9/g 1904. St. 294. 57^54 L-N. 7^38 L.W. 9f?-

Vg 1905. St. 167. 58°42 h. N. 6°i3 L. W. Yt. 1500 M. Wire 17 f?; i yd* (V); 2 y? (V).
% 1905. St. 172. 57°33 L. N. 4°26 L. E. Yt. 300 M. Wire 121 f?; 4 fc?; 5 yd* (V).
7/9 1905. St. 173. 57°52 L. N. 8°oi h. E. Yt. 600 M. Wire 3 f?.

Yt. 300 M. Wire 4 fc?.

Distribution. The above mentioned localities affirm the conclusion arrived at by Farran at the
base of the records in the literature "that Chiridius annatns is a permanent inhabitant of the North-
East Atlantic, the Norwegian Sea south of 65° N., the Norwegian Channel and the Skagerak, at depths
of from 300 to 2000 metres, and is also indigenous to all the deeper Norwegian fjords." It has been
taken by the Monaco Expedition; the records of this species from the west coast of Greenland and
from the North Polar Basin refer, as shown by Sars, really to Cli. obfiisi/rons.

According to Damas and Koefoed it has been taken at the following two stations by the
Due d'Orleans. Viz: St. 14 9/^ 1905 8o°i7 L. N. 5°40 L. E. between 340 and 600 meters (f^ with
ovisacs) and St. 23, "7/^ 77°25 L. N. 4°03 L. W. between 480 — 640 meters; as, however, nearly related
species exist, which have probably been confounded with Ck. armafus now and then, these localities
ought to be accepted with due reservation.

COPEPODA

8i

Remarks. In spite of the small differences enumerated in the description, I do not doubt that
this species is identical with that described by Sars from Norwa}', and with that which Wolfenden has
described under the name of Psaidaetiditis from the Faeroe channel. According to my investigations
the size of the specimens varied from 3-6 to 4-4 mm., the biggest being those from northern regions;
Farran's (1905) specimens measured 3-3— 3'5 mm., aud even 265; these small specimens possibly belong
to another species.

17. Chiridius nasutus n. sp.
(PI. II fig. 4a; text-figs i8a— e).

1905. pars? Chiridius armatus Boeck. Farran.

Description. f$. Size: Specimen from St. 167 2-88 mm.; anterior division 2-19 mm.; urosome 0-69.

The shape of the body is in the main like that of the preceding species, but somewhat more
slender (text-fig. 18 a). The insertion of the antennulae is apparently better removed from the tip
and the rostral spines, which are somewhat longer '' '■

and basally swollen, and directed more forwards
(text-figs 18 b—c). The anterior division is just three
times as long as the abdomen. The genital somite
(text-fig. 18 d), which has a receptaculum seminis like
that of Ch. arviatus, is about 1-5 as long as the third
and 17 as long as the fourth somite; the furcal rami
are 17 as long as wide and 17 as long as the anal
somite; the last segment is about half as long as
the third one. The antennulae, which extend some-
what beyond the end of cephalothorax, but scarcely to
the end of the abdominal somite, have the segments
24 and 25 well defined ; the measurements differ only n ' a e

in minor details, as the segment 20 is a little longer Text-fig. 18. Ch. nasutus n. sp.

^,0 ^, i o ■ T..ti 1 „ , (^l,„.- a. Head in dorsal view X 16. b. Rostrum from below X 150-

than 8000 as the segment 18 is a little longer than „ , • w i • v, < a o»„;f.i .^.^u,. »+. v sr.

"' '^ c. Head 111 lateral view X "O. d. Genital somite etc. X do.

21, and as the segment 23 is scarcely I-I as long as e. Pes IV dext. in anterior view with abnormal rami X 150-
24. The appendages are like those of Chiridms

armatus, but the Sp. of the segment 23 extends somewhat beyond the end of the segment 25. The
antennae are like those of the preceding species, but the exopodite is 1-5 as long as the endopodite.
The uiaiidibnlae and maxillae are scarcely different, and the maxillulae only by the smooth anterior
surface of the third basipodite. In the viaxillipeds the third basipodite is 1-5 as long as the second,
and 2-2 as long as the endopodite. The legs are only in minor points different from those of Ch.
ar mains; the Se of Re I in the first pair of legs extends a little beyond the end of the second seg-
ment, the articulation between the Re I and II of the second pair of legs is well developed anteriorly
as well as posteriorly, and its terminal spine has 30—40 spinules (fig. 4 a). A curious difference is
found between this species and Chiridius modestus as well as armatus in the arrangement of the
glandular pores; in the number of the pores it is, as shown in fig. 4 a, like Ch. modes tus, as a single pore

The Ingolf-Expciiition. IH. 4. jj

82

COPEPODA

was found in the three segments of the exopodites in the three last pair of legs, but in the position

of the pores, especially in Re I — II, it is most like Ch. armatus, as these are placed on tlie anterior
surface, well removed from the lateral margin.

Occurrence. This species was taken by the S/S Thor at the following 3 stations viz:

"/; 1904. St 183. 6i°3o L. N. i7°o8 L. W. Yt. 1800 M. Wire i f?.
8/6 1905. SL 72. 57°52 L. N. 9°53 L. W. Yt. 1500 M. Wire 2 f?.
V9 1905. St. 167. 57°46 L. N. 9^55 L. W. Yt. 1500 M. Wire 2 f?.

Remarks. This species, which on account of its small size, the prominent rostrum, and the
curious arrangement of the secretory pores is well distinguished fron; C/i. armatus, is certainly new
to science, as in the literature I have only found a single reference to a species of the Ch. armatus
type of a size of 2'65 mm. (viz. Far ran 1905 p. 34).

18. Chiridius modestus n. sp.

(PI. II fig. 5; te.\t-figs 19 a — c).

Description, f?. Size: Specimen from St. 183 measured 3-69 mm.; anterior division 270 mm.,
urosome 0-99.

The rostral spines are longer and more prominent tlian in Cli. arinaius, but less so than in
nastihis (text-fig. 19 b). The outline of the head is anteriorly not fairly rounded as in Ch. armafus, but

distinctly produced (text-fig. 19 a). The frontal organ is prominent,
and the distance between it and the base of the rostrum is short
/ and straight, not slightly concave as in the two other species. The
cephalothorax, which is 2'5 times as long as wide, is scarcely 3
times as long as the uro.some. The genital somite, which has a
receptaculum seminis of the usual structure, is about 1-3 times as
long as the third somite, and 17 as long as the fourth (text-fig. 19 c);
the furcal rami are i-6 as long as wide, and 1-4 as long as the
anal somite, which is a little longer than the furca; the latter
somite is scarcely half as long as the third one.

The antejinulae, which extend somewhat beyond the end
of the thorax, have the 24 — 25 segments almost fused. The ap-
pendages and the measurements are scarcely different from those
of Ch. nastitus. The antennae have the exopodite 1-4 as long as
the endopodite; the Re I has, inwards, a conical process, but no seta, and the Re II has a medial and
a terminal seta placed on a small protuberance, in addition to a basal protuberance without seta. The
viandibulae and maxillae do not show an}- features of interest, and the iiiaxillulac only differ from
those of Ch nasutus bj' slightly developed spinulation of the anterior surface of the Li 3. The third
basipodite of the maxilUpeds is 1-4 as long as the second, and 2-4 as long as the endopodite; its 2
proximal setae are placed near to each other with the articular membranes confluent. The Se Re I
in the first pair of legs extends distinctly beyond the end of the segment. In the second pair of legs

Text-fig. 19. Chiridius modestus n. sp.

a. Head in dorsal view X 16.

b. Head in lateral view X 60.

c. Genital somite etc. X 60.

COPEPODA

83

(fig. 5 a) the terminal spine has about 80 densely placed, partly fused, spinules; in other respects, except
the arrangement of pores, which, except for the more medial position is like that of 67/. obtusifrons
etc., the legs are like those of preceding species.

Occurrence. The S/S. Thor has gathered a few specimens of this species at the following
two stations.

^76 1904. St. 154. 65°27 Iv. N. 27°io L. W. Yt. ? Wire 3 f?.

"/; 1904. St. 183. 6i°30 Iv. N. i7°o8 L. W. Yt. 1800 M. Wire 2 f?.

Remarks. This species, which seems to stand between the species of Chiridius without rostrum
and Ch. iiasulics, is well characterized by the shape of the rostrum and the position of the glan-
dular pores.

19. Chiridius obtusifrons G. O. Sars.
(Plate II figs. 2 a — b; text-figs 20 a — e).

1907.
igoS.

1902.
1903.
1904.
1904?

1907.

Chiridius arniatus Boeck. Vauhoffeu, pp. 519 — 521.
— obtusifrons G. O. Sars. v. Bremen, pp. 34

—35, fig- 37-
1909. nee. Chiridius? obtusifrons G. O. Sars. A. Scott, p. 43,

pi. XLIV figs 1-3.
1913. pars. — arniatus Boeck. Stepheusen, pp. 316 — 317.

1897. Pseudocalanus ariuatus Boeck. Vanhoffen, p. 279, fig. 6.
1900. Chiridius arniatus Boeck. G. O. Sars, pp. 29—30, pi. XVII.

— — — Mrazek, pp. 521—22.
Chiridius obtusifrons n. sp. G. O. Sars, pp. 29— 30, pi. 17.

— — G. O. Sars. Wolfenden, p. 131.

— Vanhoffeni n. sp. Wolfenden, p. 117, pi. IV

fig- 23-

— obtusifrons G. O. Sars. Koefoed & Dauias,

p. 408.

Description, f?. Size: Specimen from Thor St. 214 measured 4-39 mm.; anterior division 3-12
mm., urosome 1-27 mm. Sars' specimens measured 4-2 mm. and Vanhoffens 4-5 mm.

b

The shape of the body is as figured by Sars
(cf. text-fig. 20 a). The articular membrane between
the head and first thoracic tergite and between the
fourth and fifth thoracic tergite (except in the middle)
is often wanting; in the articular membrane be-
tween the last thoracic and the first abdominal
somite chitinous lists of a rather curious structure
are found (text-fig. 20 c). According to most authors
no rostrum is observed; in several specimens, ho-
wever, the rostrum was represented by a very short
spine, sometimes showing trace of bifurcation as a
median line, when observed from beneath. The
anterior division is 2"4 as long as wide, and 2'4 as
long as the abdomen. The genital somite, which
has a receptaculum seminis of a similar structure
as in Ch. aniiatics, but more slender, is 1-2 as long

Text-fig. 20. Chiridius obtusifrons G. O. Sars.
a. Cephalosonie >( 9. b. Genital somite in lateral view X 31-
as the fourth somite; the furcal rami are almost ^ Genital somite in dorsal view X 33. d. Anal somite etc.

in dorsal view X 60. e. (Downwards to the left) pes II in
anterior view X 60. f. (In the middle above) pes III in an-
The antcnnulae, which almost extend to the terior view x 60.

twice as long as wide (text-fig. 20 d).

84

COPEPODA

posterior end of the genital somite, have the 24 and 25 segments fairly well separated; the segments
2 and S<s>g are of equal length, and a little longer than the segment 20; the segment 18 is distinctly
i-i as long as 21, and the segment 24 is a little longer than 23. The posterior seta of the segment
23 scarcely extends to the tip of the segment 24. The antennae have the exopodite almost twice as
long as the endopodite, and the third basipodite of the mandibiilac has the Si i shorter than figured
by Giesbrecht (Taf. 14 fig. 17). The inaxillulae^ maxillae and the maxillipeds are scarcely different
from those described by Giesbrecht; a small pointed process, placed behind the articular cavity of
the maxillipeds, is better developed than in preceding species (text-fig. 20 a). The first pair of legs is
like Sars' fig., but the Se Re I extends a little beyond the end of the Re II. In the second pair of
legs (text-fig. 20 e) no trace of articulation was found between Ri I — II, neither anteriorly nor posteriorly;
the articular membrane between Re I — II is anteriorly indicated by a faint line. Glandular pores
are found at the base of the respective Se of Re I— III in the last three 'pair of legs; the articular
membranes between the Re I — II in pes III — IV are scarcely better developed than in the second
pair of legs, but the articulation between Ri I— II is marked not only by a lateral incision as drawn
by Sars, but also by a faint line anteriorly (text-fig. 20 f).

The structure of the labnivi is in most respects like that of Ch. artiiattcs; the most interest-
ing differences are found at the oral surface viz: the wanting transverse row of spinules behind
the median circular spot Nr. 3, and the lateral group of spinules anteriorly which is divided into a smaller
anterior and a bigger posterior portion. The lamina labialis (fig. 2 a) consists posteriorly of a chitinous appa-
ratus which is subdivided into a median and two lateral clumsy teeth, the posterior margin of which is
somewhat striated; the lamina is gradually sloping anteriorly, and overlapped by the slightly concave
posterior margin of an almost semicircular chitinous plate. In front of the lamina labialis we observe
on the posterior wall of the pharyngeal cavity in the middle a smooth longitudinal area, and on each
side of this a minutely granular area, as seen in fig. 2 a. Laterally a series of fairly slender setae,
which are situated on a chitinous lists, apparently a continuation of that supporting the serrula
6-dentata, is found. Behind and medially, a longitudinal series of about 20 more slender setae; this
series reaches only a little beyond the anterior limitation of the lamina labialis. The number of the
serrulae behind the lamina is three, arranged as seen in fig. 2 a.

The number of series of hairs behind the labial lobes etc. is in the main like that of Gaidius
(of. fig. 7 f). The series lateral i se6ras to be wanting, series lat. 2 consists of about 30 short
delicate hairs which are anteriorly placed in a single longitudinal row, and posteriorly in an irregular
group; the series lat. 3 has posteriorly an oblique row of short hairs, on the medial side of which
we find an area consisting of about 20 short bristles, and anteriorly one or two short rows, one of
which is continued as a long row to the end of the labial lobe. The series lat. 4 is medially placed
transversely with backwards directed convexity, as seen in fig. 2 a; laterally to this, and probably be-
longing to it, a triangular group of densely placed hairs is found. The series lat. 5 is represented by
a group of densely placed short hairs, which are placed in a triangular area, pointed in front. The
connection between the two last series and the hairs on the lateral lobes was not made out.

Y (Stage V). Size: Female from St. 154 measured 3-08 mm.; anterior division 2-3 mm.; uro-
some 078 mm.

COPEPODA 85

The shape of the body is in the main like that of tlie adult, but the articulation between the
head and the first thoracic tergite was complete at least in a single specimen; a well marked fifth
somite bearing the lateral spines was found. The abdominal somites are as usual four. The male
differs from the females by the presence of a fifth pair of legs without any endopodite, corresponding
to the structure in the adult males (PI. II fig. 2 b).

Occurrence. The Ingolf Expedition has curiously enough not gathered any specimen of this
species, but the Tlior has taken it at the following stations.

"If, 04 St. 154 65°27 L. N. 27°io L. W. Yt. 800 M. Wire 85 f?, i y? (V).

"/; 04 St. 214 67°i9 L.N. i7''55 L. W. Vt. 800 M. Wire 671? (one with spermatophor), i y?.

23/7 04 St. 216 66°i5 Iv. N. i2°i3 L. W. Yt. 600 M. Wire i f?.

9/5 04 St. 70 63°35 L. N. 6°2o L. W. Yt. 100 M. Wire 12 f?.

23/7 05 St. 124 6i°o4 L. N. 4°33 L. W. Yt. 100 M. Wire i f ?.

The Danish East Greenland Expedition 1900 has gathered the species three times.

4/7 1900 3 p. m. 79°09 Iv. N. 4°36 L. W. Vertical net 300-0 i f $.

7? 2 p. m. 74°09 L. N. 11 "31 L. W. — 400—0 2 f ?.

=^4/9 12 p. m. 6i°o6 L. N. i6°26 L. W. F. 392 2 f ?.

Distribution. Nansen's North Polar Expedition found this species rather abundantly from
the surface down to a depth of 300 meters. By the S/S Michael Sars it has been taken twice in the
open sea about midway between Iceland and Norway. According to Wolf en den this species occurs
sparingly in the cold underwater of the Feeroe channel. By the Due d'Orleans this si^ecies was found
at eleven stations, most often between 300 and 600 meters, as far north as 78° N., as far east as 5° L. E.
and as far west as 16° E. W. In Eille Karajakfjord it was taken by Vanhoffen on the west coast of
Greenland.

Taking into consideration the new localities enumerated above, it seems right to regard the
species as characteristic of the deeper layers of the Arctic seas.

Remarks. The male which Wolfenden has described as C/i. rfl«//(?^"£'«/ is certainly identical
with that discribed by G.O. Sars as CIi. obtiisifrons. The species, which A.Scott with doubt refers to
this species, does certainly not belong to it, on account of its smaller size and more robust body, not
taking into consideration the distribution.

20. Chiridius gracilis Farran.
(Text-figs 21 a— d).

1905. Chiridius Poppei Giesbrecht. Fanan, p. 35.
1908. — gracilis n. sp. Farran, pp. 30—31, pi. II figs

1-3-

1909? Chiridius? gracilis F'arran. A. Scott, p. 42, pi. XI figs 1—3.
191 1? — polaris n. ,sp. Wolfeuden, pp. 211 -212, taf.

XXIV figs 9- 12, text-f. 6a-b.

Description. Size: 2'69 mm.; anterior division 200; abdomen 0-69 mm. Farran's specimens
measured 2-4 — 2.8 mm.

86

COPEPODA

The shape of the body is like Farran's description; the anterior division is 2-9 as long as
the abdomen; the furcal rami are 1-4 as long as wide (text-figs 21 a— b). The mitcnnulac differ from

those of Ch. obhisifrois by the 20 segment, which is a little longer
than the second, which is again longer than segments 8 c\j 9. The
Si I of the third basipodite of the mandibulae is longer and thicker
than that of CIi. obtusifrons, bnt shorter than that of Ch. Poppei.
In the other mouth appendages scarcely any difference was ob-
served. In the first pair of legs the Se Re I does not extend to
the end of the segment. The segmentation of the legs is better
developed than in CJi. obtusifrons^ as shown by Farran (text-figs
21 c— d).

Occurrence. Though the Thor has only taken 3 f^ (of
which one with spermatophor) ^/o 1905 St 72 57°57 L. N. 9°53
L. W. Yt 1500 M. Wire, I think that this species belongs to the
fauna of the region explored by the Ingolf Expedition.

Remarks. This species is according to Farran fairly
common on the west coast of Ireland; its range was from 280 to 1000 fathoms. I think it is extremely
doubtful whether the species which A. Scott refers to this species, from the Malayan Sea, really is identical
with the Irish species. I think that Farran is right in regarding it as a species which forms a con-
necting link between the much smaller Ch. Poppei and the much bigger Ch. obtusifrons^ of which the
former is a distinct Arctic and tlie latter a Mediterranean form.

As the females belonging to the Chiridius, as Giesbrecht defined it are very much alike, a
thorough investigation of the differences between the existing species viz. those from the Siboga
expedition, the thiee mentioned above and Ch.polaris Wolf. (p. 212), which is very nearly related to
if not identical with Ch. gracilis, is needed.

Text-fig. 21. Chiridius gracilis Farrau.

a. Genital somite in dorsal view X 60.

b. Furca X 60.

c. Pes II sin in anterior view X 60.

d. Pes III sin in anterior view X 60.

1903. Aetidiopsis rostrata n. sp. G. O. Sars, p. i6o, supplement

pis. IV— V.

1904? Faeroella multiserrata n. sp. Wolfenden, p. 117, pi. IX

figs 26 — 28.

T906? — — Wolf. Pearson, p. 13.

21. Aetidiopsis rostrata G. O. Sars.
(PI. II figs 6 a — b; text-figs 22 a— d).

907

Aetidiopsis rostrata G. O. Sars. Koefoed&Danias, p. 409.
190S? Faeroella multiserrata Wolf. Farran, p 29.
1908. Aetidiopsis rostrata G. O. Sars. v. Bremen, p. 33, fig. 35.
1909 Nee. — — — A.Scott, pp. 40— 41, pi.

V figs 13—24.

Description. i% vSize: Specimens from Thor St. 214 measured 3-8 mm.; anterior division 276
mm.; urosome 1-04. Other specimens measured 3-4 and 3-9. Sars' specimens measured 4-4 and Wolfen-
den' s 3-54 mm.

The shape of the body is like Sars' figure. The rostral spines (text-fig. 22a) are comparatively
shorter, and in shape somewhat different from Sars' figure; the frontal organ is very prominent. The
articular membrane is distinct not only dorsally, but also laterally between the head and the first
thoracic somite. The lateral spines of the thorax (text-figs 22 b) scarcely reach the middle of the
genital somite. The abdomen is in most specimens at least one third of the length of the cephalo-

COPEPODA

87

thorax, but in others it is scarcely one third. The comparative length of the abdominal somites and
the furcal rami are 32 — 24—18 — 11 — 16; the furcal rami are i-6 as long as wide. The receptacnla
seniinis are in most specimens well developed, and of similar shape as in Ch. ohtiisifrons (text-figs 22 b— c).

The mitcnnulac, which have the segment 24 and 25 well separated, reach about to the end
of the third abdominal somite; the segment 2 is V2 as long as Scv^g, which is a little shorter than
the segment 20; the segment 21 is about as long as 18, and the segment 23 is i-i as long as the 24.
The appendages are like those of Ch. obhtsifrons, but a distinct "Aestetask" is found in segment 7; the
posterior seta of segment 23 reaches distinctly beyond the end of segment 25. The antninac are like
Sars' figure, with the Re 1-4 as long as the Ri; the setae of Re I— II are arranged as described in
Ch. modest lis. The mandibulac are like Sars' figure. The maxillulac are in main features, especially
in the number of setae, like Ch. ari>iafiis\ the iiiaxiUac are
scarcely different from Sars' figure, but differ from those of
mentioned species by a small dejDression in the middle of
the exterior margin of the first basipodite, which seems to
be connected with a wide chitinous sac. The third basipodite
of the maxillipcds, is 1-5 as long as the first and second seg-
ments and almost twice as long as the endopodite.

In the first pair of legs the Se Re I extends
distinctly beyond the end of Re II. The second pair of
legs has the first basipodite greatly enlarged inwards; the
articulation between Ri I — II is wanting anteriorly; glan-
dular pores are present at the base of the Se in Re I — III;
the St has 58 .spinules (in Sar's figure 35 only). The fourth
pair of legs differs from that of the three first pairs by
wanting marginal row exteriorly of the second basipodite; its structure is in most features like Sars'
figure, and the St has about 60 spinules (text-fig. 22 d).

The anterior surface of the labruin was like that of Ch. arma/iis, but differed by the wanting
lateral irregular group of hairs in front of the transverse series. The oral surface has the hairs in
the three first groups, especiall)' the third, somewhat differently arranged, as seen in fig. 6 a; the groups
4—5 are more irregular than in this species. The lamina labialis is, as seen in fig. 6 b, in most respects
similar to that of CIi. aniiatns\ the inner longitudinal series in front of the lamina was not observed.
The longitudinal series of hairs upon and behind the labial lobes are in most features, especially in
series lateral IV — V, like those fully described in Ch. obiust/rons.

Text-fig. 22. Aetidiopsis rostrata G. O. Sars
a. Head in lateral view X 60. b. Genital somite
in lateral view X 60. c. Genital area from below

X 115. d- Pes IV dest. in post, view X 60.

Occurrence. The Ingolf Expedition "/^ 96 6-30 p. m. St. 105 65°34 L. N. f^x L. W. closing
net 700 fathoms has taken a single adult female, and the S/S Thor has gathered it at the following
three stations.

2% 04 St. 153 65^20 L. N. 27^12-5 L. W. Yt. 800 M. Wire i f?.
^Ve 04 St. 154 65°27 L. N. 27°io L. W. Yt. 800 M. Wire 3 f ?.
^V? 04 St. 214 67°i9 L. N. i7°55 L. W. Yt. 800 M. Wire 6 f?.

COPEPODA

Distribution. This species was taken twice by S/S Michael Sars between Jan Mayen and Fin-
marken at a depth of from 500 to 1000 metres. According to Koefoed and Da mas the si^ecies is
found "a) dans la mer du Gronland: de 60 jnsqn' a 1800 metres an moins, b) dans la mer de Norvege:
jamais observe a moins de 400 metres" (p. 409). By the Due d'Orleans it was gathered at 10 stations
as far east as 2°4o L. E. at 79° L. N., and as far west as 15° L,. W. at 78° L. N. near the east coast of
Greenland. The expedition has at the most northern station '^/^ 1905 taken adult males as well as
females and young ones. According to Wolfenden his Facroella imdfiscrrafa "is not uncommon in
the deep water of the Fseroe channel, and has been traced by the writer as far south as Valentia in
Ireland" (p. 117). This species is, according to Farran, "occurring not uncommonly from 400 to 1000
fathoms" off the west coast of Ireland.

Remarks. I do not doubt that the specimens which I have examined ought to be referred
to Sars' species, in spite of the smaller size, the shorter rostral spines, the lateral spines which scarcely
reach the middle of the genital somite, and the comparatively longer abdomen; from Wo 1 fen den's
very imperfect description it differs by the well marked segmentation between the head and first
thoracic tergite, by imperfect segmentation of Ri pes II, and by more coarsely spinulated terminal spines
of the legs.

Though Sars (cf. Farran p. 20) has accepted Wolfendens species as distinct from his own,
and in spite of the different distribution, I am fairly convinced that they belong to the same species;
the southern variety has sometimes comparatively few dentations in the St pes II (Farran has found
32 only). Further examination and comparison of the different forms are needed before the question
can be solved. It is to be regretted that neither Wolfenden nor Damas & Koefoed, who have
examined the males as well, have given any description of them.

If Scott's figure of the antennulae of his A. rostrata Sars is correct, the Sp. of the segment
23 does not reach the end of the segment 24, and a new species ought to be established.

Wolfenden has later on established 2 new species Facroella minor and aiitarctica (1911 p. 214);
it is remarkable that this author does not accept Sars' name, 'which without doubt has the priority.
Tliat the species are cogeneric does not seem to be doubtful ; whether the genus is quite natural is very
doubtful. To solve this rather vexed question I have not sufficient material of the different genera.

22. Udinopsis armatus Vanhoffen.

1S95. Bradyanus armatus ii. sp. Vanhoffen, p. 322

1S97. — — Vanh. Vanhoffeu, p. 280, fig. 17.

1902. pars. Bradyidius armatus Vanh. Mrazek, p. 521.

1903. Udinopsis similis u. sp. G. O. Sars, p. 34, pi. XXI.

1907. Udinopsis armatus Vanh. Vanhoffen, pp. 517 — 519, taf. 21

fig. 24.

1908. Bradyidius similis G. O. Sars. v. Bremen, p. 32, fig. 32.
1913. Udinopsis armatus Vanh. Stephensen, p. 317.

This species, which has not been secured by any of the expeditions, has been mentioned from
"Lille Karajak Fjord" on the west coast of Greenland, and Sars has found it in the inner part of the
Stavanger Fjord, where "it only occurred close to the ground", "the depth ranging from 50 to 100
fathoms".

This species is not identical with Bradyidius arviatns Giesbr. of Scott, Giesbrecht-Schmeil
and Wolfenden. Stephensen has wrongly given Bradyidius armatus v. Bremen as partly .synonj'-
mous with it.

COPEPODA

89

23. Gaidius tenuispinus G. O. Sars.
(PI. II fig. 8 a; pi. Ill fig.s 2 a— n; text-figs 23 a— j).

1907. Gaidius teuuispiuus G. O.Sars. Vanhoffen, pp. 521 — 522,

taf. 21 fig. 27, taf. 22 fig. 33.

1907.

— — G.O.Sars. Koefoed&Damas,p.4o8.

1908.

— — — Farran, p. 32.

1908.

— — — V. Bremen, p. 36, fig. 39.

1909. Nee.

— similis Th. Scott. A.Scott, pp. 51—52, pi. VII

figs I — II.

1911.

— tenuispinus G. O. Sars, Farran, p. 97.

igii?

— — — Wolfenden, p. 223, figs

II a— b.

1913-

— — — Stephenseu , pp. 315

-316.

1900. Chiridius tenuispinus n. sp. G. O. Sars, p. 67, pi. XVIII.
1902. Gaidius tenuispinus G. O. Sars. Mrazek, p. 512.

1902. — borealis n. sp. Wolfenden, p. 365.

1903. — tenuispinus G. O. Sars. Norman, p. 136.
1903. Chiridius tenuispinus G.O.Sars. G. O. Sars, pp.30 — 31,

pi. XVIII.

1903. Gaidius tenuispinus G. O. Sars. G. O. Sars, p. 162, pi. VI,

suppl.

1904. PGaidius puugens Giesbr. Wolfenden, p. 131, pi. IX fig. 43.

1905. Chiridius tenuispinus G. O. Sars. Th. Scott, p. 223.

1905. Gaidius tenuispinus G. O. Sars. Farran, p. 33.

1906. — — — Pearson, p. 13.

Description, f?. Size: Specimen from Thor vSt. 70 measured 3-84 mm.; anterior division 2-94 mm.;
urosome 0-90 mm. Two specimen.s from Thor St. 285 measured 2"6 -f- 0'62 = 3'22 mm. and 2^9 + o-8
= 37 mm.; specimens from Thor St. 183 measured 27+07 = 3-4 mm. Sars' specimens measured 3-8
and Wolf en den's 3-8(1904) aud3-25 (1911) mm. Van hof fen's specimens 3-9 and Farran's (1905)3-2 mm.

The shape of the body is scarcely different from Sars' figure, and no trace of segmentation
between the fourth and fifth thoracic somite was observed; the lateral spines of the thorax are distinctly
set off, and extend almost to the end of the genital somite (text-fig. 23 a). The rostrum is not, as set
forth by most authors, undivided, but shows as seen in fig. 2 a (PI. Ill) trace of bifurcation.

The length of the abdomen, compared to that of the anterior divisioi:^ varies from about '/a
to '/4- The genital somite, which as seen in fig. has a short and well marked receptaculum seminis,
well distinguished from the stalked one in Chiridius^ is somewhat deeper and wider than long, and
r6 as long as the third somite. Tlie furcal rami are i-6 as long as wide and a little wider than the
anal somite is long.

The antcnmilac reach to about the end of the third abdominal somite and have the measure-
ments distinctly different from those of G. brevispimis on account of the shorter distal segments; the
segment 2 is i-2 as long as 8039, which is almost 1-3 as long as segment 13 and only a little shorter
than segment 20; the segments 19 and 22 are almost of equal length, and almost i-i shorter than
segment 2. The appendages are like those described by Giesbrecht in Gaetanus ariiiiger with
"Aesthetasken" in segments 3, 4 and 6 and Spr. in segment 13; the posterior seta of the segment 23
is ringed, and about three times as long as the segments 24 and 25, which are well separated.

The antennae have the Re 1-3 as long as Ri; the Ri I is distinctly twice as long as Re II;
this is about twice as long as Re I, and about twice as long as Re III— VI, and about -/j as long as
Re VII. The Re II has the short Se 2 placed on a rather prominent process, (PI. Ill fig. 2 e), like
that found in Giesbrecht's fig. 19 Taf. 14 of Gaetanus anniger^ and the Se 3 is somewhat longer.
The mandibulac differ from Sars' figure by two slender Si of the third basipodite, and are in main
features like those in Giesbrecht's G. aniiiger. The uiaxMulae are rather elongated, like Gies-
brecht's figure of Gaetanus miles (Taf. 14 fig. 21); the Li I possesses on the anterior surface about 10
fairly strong teeth, and on the posterior surface near the base of S 11 about 10 similar ones; the L,i II
has 4 setae, and the Li III 5 + a sensory lobe and anteriorly a fairly strong spinulation, the Basp. Ill

The Ingolf-Expedilion. HI. 4. 12

go

COPEPODA

has 4 Sp and i Sa but no spinulation anteriorly; the Ri I has 3 Sa + i Spi the Ri II has 3 Sa -j- i Sp
and the Ri III 5 S. The exopodite has 11 setae, and the Le has 7 long -f 2 shorter ones. The maxillae
are very characteristic by the strongly and suddenly convex outer margin of the basipodite, with a
short concavity in the middle (text-fig. 22 b) ; the lobe I possesses a quite rudimentary spinelike Sp. i
and a Sp. 2, which it about twice as long as the lobe itself; the strong spine of lobe IV is somewhat
longer but scarcely stronger than that of lobe V. The third basipodite of the jnaxillipeds is i-2 as long
as Basp. I — II and three times as long as Ri; the exterior margin of the second basipodite has no trace
of lamina, and its fourth lobe bears 3 hairs and a sensory process (fig. 2 c PI. III).

The Jirst pair of legs has the articulation between Re I and II indicatad by a faint line
anteriorly, and sometimes a small incision laterally; the Se Re I is wanting; the St has the usual

Text-fig. 23. Gaidhti tentiispinus G. O. Sars.
a. 9- Abdomen in lateral view X 33- b. Maxilla .sin. in posterior view. c. Pes IV sin. in posterior view X 82. d. cf. Pes
V sin. X 140- s. Maxilla dext. in anterior view to show position of parasites X 60. f and g: the same parasites X 150-

h— j. Contorted bodies attached to the bod3-wall X 400.

characteristic structure (PI. Ill fig. 2 d). The articulation between Re I and II in pes II and Ri I and
II is as shown in Sars' figure well developed; the St has 25 teeth. The fourth pair of legs has
the Re III three times as long as wide and the St. has 25 teeth, partly armed with accessory ones; the
first basipodite has the usual marginal hairs substituted for by 30—40 stiff thin lamellous bristles,
which are placed in about 5 rows along the inner margin, and in 2 — 3 parallel ones on posterior surface,
the more posteriorly the more distally placed. The arrangement and number of the glandular pores
in pes I — IV are as in Cli. oblusij'rons.

The lateral view of the labriiiii is like that of Chiridiiis^ but the different parts are less
prominent. The oral surface of the labrum (PI. Ill fig. 2 e) is, as seen by comparing figures,
distinctly different from Gaidiiis brcvispimts\ the five groups, as well as the sixth more transversely

COPEPODA 91

placed one (not seen in fig.), are well separated ; the setae aronnd the median circnlar spot Nr. 4 are
well developed.

The lamina labiaUs is almost smooth, bnt in other respects scarcely different from fig. 7 f (PL
II), and the area in front of it is most like fig. 5 e PI. III. The longitudinal lateral series of hairs
placed behind the lamina labialis are in details somewhat different from those of G. brevispiniis] the
3 posterior groups of the third series are better separated, and without direct connection with the
anterior part; the proximal and distal groups of the series V seem to be fused.

fc?. Size of specimen from Thor St. 183 was 3-01 mm.; anterior division 2'3 mm., urosome 071.

The shape of the body is scarcely different from Sars' fig. PI. VI (supplement). The rostrum
is fairly long and shows, terminally, trace of bifurcation (PI. Ill figs. 2 f — g).

The antcnmilac have the segments Scssg partly fused with 10, and the segments 12 and 13 with
14; the segments 20 and 21 and 24 and 25 are completely fused; the appendages are scarcely different
from those of Aetidius arniatus (cf. Giesbrecht Taf. 14 fig. 15). The measurements differ from those
of the female by the segment 22, which is i-i as long as segment 17 and 1-2 as long as segment 2. The
structure of the anfeniiac is in most respects like that of the female, but the Si 2 of Re II is not
placed on a small process. The manducatory portion of the mandibulac (cf. fig. i d) is even more
thin-skinned than in G. brevtspimcs, but has rudimentary teeth; the third basipodite has no setae,
and those of the exopodites and endopodites are better developed. The inaxilhilac differ from those
of G. brevispimis (fig. i e) by a fairly long Li 2 with a number of rounded sensory organs. The maxillae
(PI. Ill fig. 2 h) are small, thin-skinned organs, which in the main preserve their original shape;
the exterior margin of the basipodite has no convexity; the inner surface possesses an indistinct
number of short partly fused lobes, the setae of which are more or less transformed into thin-skinned
more or less setiformed appendages with a swollen base; the Ri has a few setae of usual form. The
two first segments of the maxillipeds possess only the fourth lobe.

The Jirsl pair of Irgs has, as shown in fig. i g, the Se Re II represented by a minute seta, and
the St. is as usual in the male almost straight (PI. Ill fig. 2i); the second to the fourth pairs of legs
are scarcely different from those of the females, except by the smooth inner margin of the second basi-
podite of the fourth pair of legs. The fifth pair of legs is on the right side in the main like Sars'
figure; the Ri (PI. Ill fig. 2 1) is distally swollen and contains clear alveolar structures; the Re I (I ooH ?)
has in most specimens a lateral protuberance, and shows trace of segmentation (fig. 2 m); the Re
II has inwards a lamelli-form process which surrounds a shallow cup facing backwards and outwards (fig.
2 n, cf. fig. ij); the Re III is elongate and curved with a terminal hooked hairy process. The left leg
(text-fig. 22 d) appears more slender than in Sars' figure; the Ri which shows a trace of segmentation
is long and slender, distally somewhat enlarged and bearing a short hair; the Re 2 has inwards a hairy
protuberance (fig. 2J), and the Re 3 is very elongate with a distal fairly long Se and a St. (fig. 2 k).

Y (St. V). Size of female from St. 70 3-15 mm.; anterior division 2-51 mm., urosome 0-64.

The shape of the body, except for the usual segmentation of the abdomen, is as in the female,
the antennulae extend almost to the end of the abdomen. The mouth appendages are scarcely in
any features of interest different from those of the female. The articulation between Ri I and II of
pes II is less developed than in the female; the glandular pores were scarcely different. Along the

92 COPEPODA

inner margin of the second basipodite of pes IV a few lamellous setae like those of the adult females
were found in the young females, but in the males a few marginal hairs of usual structure were found.
The fifth pair of legs in the males is as seen in fig. 8 a (PI. II) rather slender.

Y$ (St. IV). Size: A single female from Thor St. 165 1905 measured 2-06 mm.; anterior di-
vision 1-67; urosome 0-39 mm. The antennulae reached to base of furca; the shape of the body is in
the main like that of the adult females, but the abdomen has as usual only three somites. The
structure of the appendages was not examined in details.

Parasites. In several adult females of this species curiously twisted bodies (text-figs 22 h— j)
to the number of one or two were found, now on the right and now on the left side; they are by a
delicate stalk fastened to the skin of the bod>- wall between the insertion of the maxillae and maxil-
lulae; their content is finely granular. About their nature I do not at present wish to express
any opinion. The\- were found in the following number of adult females from 5 stations viz. i from
Ingolf St. 20, 25 from Thor St. 152 '^/^ 1904, 20 from Thor "je St. 153 and 4 from '"/^ 1904 St. 78.
At St. 152 and 153 they was generally found together with the "para.sites" to be described.

In a great number of adult females of this as well as of the following species elongate obovate
bodies (text-figs 22 e— f) were observed; they are by a stalk and a terminal disc fastened to the chitin
of the niaxillulae (in a specimen from Ingolf St. 19 f. inst. to a seta of L,e), but especially of the max-
illae. These structures are of somewhat different shape in the various animals, with the tip more or
less pointed; they consist of a transversely striated wall, which, in contrast to the stalk, is dissolved
into a solution of potash and a content with vacuoles but without distinct nuclei in glycerin prepara-
tions. The stalk is hollow and widened out towards the sac, which is here more or less pointed.

These structures were sometimes found on the left sometimes on the right side to the number
of one to four; they were found in the following number of specimens in one sample from Ingolf, and
in II from Thor: viz: Ingolf St. 19 2 specimens; Thor St. 152 ('^/g 1904) 25 specimens, St. 153 (-%
1904) 20, St. 154 (^76 1904) 3, St. 78 (■% 1904) 8, St. 285 C/g 1904) 5, St. 214 ("/7 1904) I, -St. 183
("/? 1904) 6, St. 104 (24/j 1904) 10, St. 164 (29/8 1905) I and St. 72 ("/e 1905) 3 specimens. It is rather
curious to notice that the distribution of these "parasites", which in some features are not unlike
spermatophors, is very irregular within the area; they were most common in Denmark Strait, and
very scarce at the southern stations. At the station (Thor 9/^ 1904 St 70) at which the greatest num-
ber of specimens of G. tetiuispiuus viz 890 f ? were collected, these structures were not observed.

Occurrence. The Ingolf Exp. has gathered this species at the following stations in
Davis Strait

^Ve 1895. St 24. 63°o6 L. N. 56°oo L. W. V.' 200-0 fathoms. Temp, at surface 4-2° C. i f?.

26/6 1895. St 25. 63°3o L. N. 54°25 L. W. V.' 200 -o fathoms. — 2-9° C. if?.

V7 1895. St 27. 64°54 L. N. 55°io L. W. V.' 200—0 fathoms. — 3-9° C. i f?.

In the Atlantic south-east of Greenland it has been taken at 2 stations.

^°/6 1895. St 20. 58°20 Iv. N. 4o°48 L. W. V.' 200—0 fathoms. Temp, at surface 6-i° C. 2 f ?.

'8/6 1895. St 19. 6o°29 I^- N. 34°i4 L. W. V.' 300—0 fathoms. — 9° C. 5 f?,

I y? (V); lycfW.

COPEPODA

93

In Denmark Strait it has been taken.

21/5 1895. St. II. 64°34 L. N. 3i°i2 L. W. V.' 2cx)— o fathoms. Temp, at surface 8-2° C. i f?.

The S/S. Thor lias in Denmark Strait at four stations from 1904 taken numerous specimens,
of which numerous were infected with "parasites" of both kinds.

'y/6 1904. St. 152. 65°oo L. N. 28°io h. W. Yt. 800 M. Wire about 100 f?; i y? (V); i yc? (V).

2% 1904. St. 153. 65°2o L. N. 27°i2-5 L. W. Yt. 800 M. Wire 80 f?; 3 y? (V); 2 yc? (V).

^Vft 1904. St. 154. 65°27 L. N. 27°io L. W.* Yt. 800 M. Wire 85 f?; i y? (V); i yc? (V).

is/e 1904. St. 150. 65°50 L. N. 26°53 L. W. Yt. 400 M. Wire i f?.

In the Atlantic south of Iceland the S/S. Thor has taken numerous specimens from deeper
layers; comparatively few specimens were infected with the said parasites.

Thor >% 1904- St. 78. 63°o8 L. N. 2i°30 h. W. Yt. 750 M. Wire 50 f ?.

'"Z; 1904. St. 180. 6i°34 h. N. 19=03 L. W. Yt. 400 M. Wire 26 f $.

Vg 1904. St. 285. 62°49 Iv. N. i8°4o L. W. Yt. 500 M. Wire 125 f?; 3 yc? (V).

"/y 1904. St. i83.6i°30 L. N. i7°o8 L. W. YL 1800 M. Wire about 100 f?; 14 fd'; 4 y? (V);

7yc?(V).
24/5 1904. St. 104. 62°47 L. N. i5°03 L. W. Yt. 1500 M. Wire 35 f?; 2 yd"' (V).

In the Iceland-Fseroe channel the S/S. Thor has taken the species at four stations a single
time in big numbers, only few siDecimens bore "parasites".

Thor 29/8 1905. St. 164. 6i°20 h. N. ii°oo L. W. Yt. 300 M. Wire i f?.

"/j 1904. St. 99. 6i°i5 L. N. 9°35 L. W. Yt. 1700 M. Wire 2 f ?.

9/5 1904. St. 70. 63°35 L. N. 6°2oL. W. Yt. 100 M. Wire 890 f?; 4 y? (V); 7 yd* (V).

27/^1904. St. 124. 6i°o4L. N. 4°33 Iv. W. Yt. 100 M. Wire 28 f?.

Outside the Ingolf area the S/S. Thor has taken the species at the following stations.

Thor '5/6 1905. St. 82. 5i°oo D. N. ii°43 L. W. Yt. 1200 M. Wire 2 f ?.

76 1905- St. 72. 57°52 h. N. 9°53 L. W. Yt. 1500 M. Wire 23 f?; i y? (V); i ycT (V).

31/8 1905. St. i67.57°46 L. N. 9=55 h. W. Yt. 1500 M. Wire 8 f?; i y? (V); 3 yd* (V);

I y? (IV).
North of Iceland the species was taken by S/S. Thor at a single station.

"/; 1904. St. 214. 67°i9 L. N. i7°55 L. W. Yt. 800 M. Wire 60 f?; 2 fd*; i y? (V); 3 y^ (V).

Distribution. The species has previously been recorded fairly common in the eastern part of
the north polar basin crossed by Nan sen; specimens were found as far north as 85 Lat. N., and
here near the surface; at the other stations they were found at considerable depth. From Spitsbergen
it has been recorded by Mrazek. In the ocean lying between Spitzbergen and Greenland it was
found fairly common from altogether 18 stations, scattered all over the area crossed by the Due d'Or-
leaus as far north as 80° L. N. 2°47 L. E. ; its range was between 100 and 700 meters in depth. In the
Norwegian Sea it was found a few times between Finmarken and Jan Mayeu between 500 and 1000

94

COPEPODA

meters. From the west coast of Greenland it has been recorded from "Lille Karajakfjord" by Van-
lioffen. It is, as seen from the above, fairly common in the Iceland-Fseroe channel between loo — o
meters, and so it is in the Fseroe-Shetland channel ; its shallowest record here is accordiuo; to Far ran
(191 1 p. 97) "from a haul of 100 — o meter in 143 meters of water from a station lying to the east of
Shetland". It has as far sonth as 55° L. N. "several times been met with in small numbers in the
deep water of the Atlantic slope off the south west coast of Ireland at depths of from 500 to 600
fathoms". The species has not been taken by the Monaco; the records from the Gauss and the Siboga
Expeditions seem to be very doubtful, and shall presently be discussed.

The Ingolf and the Thor's records of this species from Baffin Bay, Danmark Strait, the sea
north of Iceland and the Atlantic south of Iceland as far south as 60 to 51° L. N. complete the picture
of this species as a North Atlantic and arctic species from the intermedial layers.

Remarks. That the described species is identical with Sars' G. tciiuispinus does not seem
doubtful, in spite of the slightly bifurcate rostrum and the stiff broad bristles on the inner margin of
the second basal segment of the fourth pair of legs, which were not mentioned by the author; the
latter character was well described by Wolfenden for his species G. bor calls \ Wolfenden has later
on identified his species with G. tenulsplnus, but has in the list of species, probably by a slip of the
pen, given it the name G. pimgens Giesbr.

Wolfenden has identified specimens from Caj) and the Antarctic ocean with the northern form;
he has examined specimens from the northern as well as the southern regions without being able to
find great differences; he may be right; but as the differences between the species are often so small,
and as too few characters are generally used b)- the authors, I prefer to look forward to further in-
vestigations, not the least on account of the different localities. It is on that account that I have
given so full a description of this species.

A Scott is certainly right in regarding his father's species Enchwtc Hcssll var. sltnlHs (1894
pp. 58 — 59 PI. VI figs 24 — 25) as being related to Gaidms\ but as its size is only 2"2 mm., as the terminal
segment of the left pes V is somewhat swollen at the base and as it "wants the prominent rostrum
of Euc. Hessef'' (his figure does not show any rostrum), I do not think his identification ought to be
accepted. A.Scott identifies his G. si mills Th. Scott with G. piuigciis Gbt; in this he may possibly
be right. He writes (p. 52). "I regard the form described by Sars as Galdlus tcttulsplnns ... to be
identical with this species". His figures of the pes V and of the rostrum of the male, which are
somewhat insufficient, do not support his view.

24. Gaidius brevispinus? G. O. Sars.
(PI. II figs. 7 a — h; pi. Ill figs. la — ^j; textfigs 24 a— i).

1900?
1902?
1903?

1903?
1904.

Chiridius brevispinus n. sp. G. O. Sars, p. 68, pi. XIX.
Gaidius — G. O. Sars. Mrazek, p. 521.

— — — G. O. Sars, pp. 162 —

163; suppl. pi. VI.

— — — Norman, p. 136.

— major n. sp. Wolfenden, pp. 114 — 115; pi. IX

figs 7-8.

1905 ? Gaidius brevispinus G. O. Sars. G. O. Sars, p. 3.

1905? — affinis n. sp. G. O. Sars, p. 9.

1905. — brevispinus G. O. Sars. Farrau, p. 33.

1906. — — — Pearson, p. 13.
1908. — — — V. Bremen, p. 35.
1908. — affinis — Farran, p. 32.

COPEPODA

95

Description. f$. Size of specimen from Thor St. 183 4-05 mm.; anterior division 3-13 mm.,
iirosome 0-92 mm. Sars' specimens measured 4-8 mm., Wolfeiiden's specimens 4-65 mm. and Far-
ran's specimens measured 3'9— 4*5.

The shape of the body is practically as figured by Sars, except for the distinctly longer lateral
spines of the thorax, which are directed downwards and backwards. The rostrum is not undivided
as stated by Sars, but is, as shown in fig. 7 a (PI. 11), distinctly bifurcate terminally. On each side of
the vulva a somewhat triangular plate was found, and a short receptaculum seminis was observed
(fig. 7 b); the structure of the genital apparatus was rather complicated, but was not examined in the
details; figs 7 b—c will give an impres-
sion of its structure. The furcal rami
are 1-4 as long as wide, and a little
shorter than the anal somite.

The antennulac do not reach
to the end of the anal somite, but only
somewhat beyond the end of the geni-
tal somite. The segment 2 is 11 as
long as 8059, which is scarcely I'l as
long as segment 13, and i-2 shorter
than segment 20; segment 19 is a little
longer than 20 and 22 which are of
almost equal length, and longer than
segment 2. The appendages differ from
those of G. tcnuupinus by the presence
of a Sp. in segment 13.

The antouiac have the Re

about I'S as long as Ri, but are scarcelv ^ ^ -• . n j- >. >*-..<- r> «,,„

•J " ' - Text-fig. 24. Giiiaiiis brevispimis O. O. oars.

different in other respects. The maxil- a. f 9. Head from the left with parasite attached to uiasilla X 18. b. f9.

Pes I sin. in ant. view X 80. c. Pes II sin. Ri in ant. view X 80. d. fd".
hdae differ from those of G. temiispimts Rostrum x 57. e. id- Abdomen x 33- f- fd". X 9- g- Y9. (Stage V) X 33.
by Ivi 3, which only bears 4 setae in h. Y9. Abdomen lateral view X 33- i- yP- Pes II Ri in ant. view X 80.

addition to the sensory lobe, and by the Re III, which possesses 6 Sa + i Sp. The maxillae (fig. 7 d)

have the exterior margin less strongly convex than the preceding species; the Sp. 2 of the first lobe is

three times as long as the lobe itself, and the Sp. of lobe IV is stronger as well as longer than the

corresponding Sp of lobe V. The viaxillipcs differs from those of the preceding species by a rounded

lamelli-form protuberance on the exterior surface of the second basipodite (fig. i a). The articulation

between the Re I— II of the Jirst pair 0/ legs is better developed than in G. tenuispirms (text-fig. 24 b),

and so is the articulation between Ri I— II of the second pair of legs (text-fig. 24 c), the St. of pes II

has only 19 teeth; along the inner margin of the second basipodite of the fourth pair of legs distally

and posteriorly one to two rows of broad stiff bristles were observed (fig. i c).

The oral surface of the labnim has a well developed longitudinal series of hairs, which

are, however, only indistinctly divided into the usual 5 groups as seen in fig. 7 f; group III is

96 COPEPODA

fairly well marked, and group IV has in addition to the inner series a lateral one with 10 short
hairs. The transverse series around the fourth pair of central spots is less prominent than in the
preceding species. The lateral group of hairs is assymmetrical in one of the examined specimens. The
granular lamina labialis with the area in front of it is shown in fig. 7 f. Behind the lamina labialis
four partly fused groups of short spines are placed near the middle line. On the area labialis and the
lobi labiales altogether 5 longitudinal series of hairs (PI. II fig. 'ji S' — Ss) arranged as shown in
figure were found.

i^. Size of specimen from St 183 Thor 1904 was 3-34 mm.; anterior division 2-53 mm.; uro-
some 081 mm. Wo Ifen den's specimen measured 3-1 mm.

The shape of the body is practically like that of preceding species, but for the shorter lateral
spines (text-figs 24d— f). The antennulae extend almost to the end of the abdomen; the segment 22
is 1-4 as long as the segment 17, but in other respects they are scarcely different from those of pre-
ceding species. The antennae are comparatively more clumsy, with comparatively shorter Re; the
manducatory part of the mandibulae is comparatively more thin-skinned (PI. Ill fig. id), but in
other respects the mandibulae are scarcely different. The viaxillulae (fig. 1 e) are fairly well devel-
oped; the Le I has as usual 9 setae; the Li I does not possess any setae, but a number of short
rounded sensory organs; the Li II which is quite rudimentary, and the Li III which has at least one
real setae, possess similar organs. The third basipodite has at least 2 setae and the Ri I— III 3 +
3 -|- 6 setae. The Re has as usual 11 setae. The maxillae are scarcely different from those of pre-
ceding species (cf. fig. 2 h). The maxillipeds (fig. i f) have the third basipodite 1-3 as long as the
basipodites I — II and 2.5 as long as Ri; the basipodites I — II have a rudimentary Li I and a fairly
well developed Li IV.

The first pair of legs has the articulation of Re I well developed (fig. i g), but not only Se
Re I but also Se Re II are completely wanting. The St. Re III of pes II has 37 teeth, and the inner
margin of the second basipodite in the fourth pair of legs is smooth and has, as seen by comparing
figs 7 g and 7 e another shape than in the female. The Jifth pair of legs (PI. Ill fig. i h) is very simi-
lar to that of G. fenuispinus, but the basal segments are comparatively shorter, especially the third one
of the right side. The left endopodite shows no trace of segmentation, and has no small terminal seta;
the left Re III has, as shown in fig. i i, a rather characteristic structure.

Y (Stage V). Size of female from St. 183 Thor 3-22 mm.; anterior division 2-53 nnn. ; uro-
some 0'69 mm.

The shape of the body, except for the structure of the abdomen, is scarcely different from that
of the adult female. The antennulae extend distinctly to the end of the last abdominal somite; the Sp.
of segment 23 is only 1-5 as long as the segments 24—25. Tlie maxillulae have only 10 setae in Re, the
exterior margin of the basipodite of the maxillae is less distinctly convex, and the laminous process
of the exterior surface of the second basipodite of the maxillpeds is less prominent, with a distal tooth.
The pes II has the articulation between the Ri I— II slightly developed (text-fig. 241), and the mar-
ginal hairs of the second basipodite of the fourth pair of legs are in the male only fewer (about 10)
than in the pes III, but not different; in the female, however, not only the number is smaller (17 against

COPEPODA 97

32), but the hairs are stiffer, and the row is distally turning around margin posteriorly. The fifth pair
of the legs (fig. 7 h) is in several respects different from that of G. fenuispimis (fig. 8 a).

Parasites? "Sacshaped" structures, like those of preceding species in a similar position were
found in a single female from Thor St. 152 and in 29 females from Thor St. 183.

■ Occurrence. The Ingolf Expedition has not taken this species, but the S/S. Thor gathered it
at a few stations in Denmark Strait and south of Iceland yiz:

'9/6 1904. St. 152. 65°oo L. N. 28°io L. W. Yt. 800 M. Wire 11 f?.

2% 1904. St 153. 65°20 L. N. 27°i2-5L. W. Yt. 800 M. Wire if?.

Vg 1904. St. 285. 62°49 L. N. i8'4.o L. W. Yt. 500 M. Wire i fc?.

"l-j 1904. St. 183. 61=30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 160 f?; 3 f<?; 10 y? (V); 42 yd" (V).

24/5 1904. St. 104. 62°47 Iv. N. i5°o3 L. W. Yt. 1500 M. Wire 2 f?.

Distribution etc. As the circumscription of this species is not quite sure, I feel obliged before
discussing its distribution, to write a few words about the synonymy.

The described species differs from Sars' G. brcvispimi-s by the somewhat smaller size, by the
divided rostrum and by the much longer lateral spines; as Sars does not seem to have realised the
importance of the characters found in the laminous process of maxillipeds and in the curious setae of the
second basipodite of pes IV, the fact that he does not mention these characters is scarcely of impor-
tance. Wolfe n den's description of the female as well as of the male is very incomplete; the females
are bigger than my specimens, and the lateral corners seem to be like those of my specimens.
Far ran has (1908 p. 32) examined specimens from the west coast of Ireland, which, as far as his few
remarks go, show exactly the same differences from Sars' description as my specimens do; really I
do not doubt that they belong to the same species. Far ran has, however, referred his specimens to
Sars' G. a/finis, and Sars has himself confirmed this identification, though his original specimens of
G.affiuis only measured 3-6 mm. Sars' description is too incomplete to be of much value. Though
Sars regards G. brcvispinus as well as affinis from the Monaco Expedition as different species, it is
most probable that the animals which are recorded from the Fseroe channel and the north-east
Atlantic under the name of G. major, affinis and brcvispinus ought to be referred to the same species,
varying in size from 3-6 to 4-65 mm. If this species is not identical with G. brcvispinus its name ought
to be G. major Wolf. This species or variet>- is distributed as far north as Denmark Strait and
tlie FEcroe-Iceland channel, and is found as far south at least as 50° L. N.; G. brcvispinus proper
which, as seen above, differs from the southern form by the larger size and shorter lateral spines, has been
taken in the western part of the polar basin crossed by Nansen (at 84° L. N. rather plentifully), once
in the sea between Finmarken and Jan Mayen, but rather curiously not in any of the numerous
samples brought home by the Due d'Orleans.

From G. intcrnicdius Wolf, it differs by the less pointed lamina of the basipodite of the
maxillipeds.

25. Gaetanus Kruppi? Giesbr.

(PI. Ill figs 3 a— h; text-figs 25 a— o).

April 1903? Gaetamis Kruppi n. sp. Giesbrecht, p. 202, pi. « 1903? Gaetanus arniiger Giesbr. J. C. Thompsou, p. 17.

VII fig. 8, pi. VIII fig. 29. 1 June 1903? — major n. sp. Wolfenden, p. 125.

The Ingolf-Expcdition. III. 4. ^3

98

COPEPODA

1903? Gaetanus anniger Giesbr. Norman, p. 137.

1904?

1905.
1905.
1906.
1908.
1908?

major Wolf. Wolfeudeu, p. 114, pi. IX figs

7-S.

— — Farran, p. 33.
Kruppi, Giesbr. G. O. Sars, p. 4.
major Wolf. Pearson, p. 14.

— — Farran, pp. 36-37.

— — V. Bremen, p. 40, fig. 45.

190S? Gaetanus Kruppi Giesbr. v. Bremen, p. 41, fig. 47.

190S? — major Wolf. Wolfenden, p. 31.

190S? — Kruppi, Giesbr. Wolfenden, p. 32.

1909 9? — — — A. Scott, pp. 48-49, pi.

IX figs 9-15.
. (J "ec. — — - A. Scott, pi. X figs i — 9.

191 1? — major Wolf. Wolfenden, p. 231.

.\IV

VIII -I.\

Text-fig. 25. Gaetanus Kruppi Giesbr.
a. f9. Head X 33- b. f9. Abdomen X 33- c. id- Head X 33- d. YcJ (st II). Head X 33- e. Y (st. HI).
Abdomen X 33- f- Abnormal spec. Head X 33- g- fd. Anteunula sin. segments 8009 — 17 X 33- h. Intestinal
tract X 9- i. Maxilla dext. in post, view X 57- j- Maxillipes sin. in post, view X 57- k. Maxillipes dext.
in anterior view X 57- 1- Ycf (st IV). Maxillipes sin. in anterior view X 57- m- YcJ (st. III). MaxilUpes

X 57- n-o. Yd" (st. V — IV). Pes V anterior view.

Description. f$. Size: Specimen from Thor St. 104 measured 5.4 mm.; anterior division 4-2
mm., urosome 1-2 mm. Wolfe n den's specimens measured 5 nmi.

The body, which appears moderately slender, is 27 as long as wide, and has a well developed
frontal spine (text-fig. 25 a), which is directed forwards and slightly downwards, and smoothly continued
into the dorsal outline of the body. The rostrum is short, and is terminally slightly bifurcate. The

COPEPODA 99

lateral spines of the fifth thoracic tergite (text-fig. 25 b) are suddenly set off, slightly divergent and
reach the middle of the genital somite. The anterior division is 3-5 as long as the urosome, which
has the 4 somites and the furca of the following relative length viz. 46, 23, 19, 15 and 21; the furcal
rami are about rz as long as wide. The genital area is similar to that of Gaidius (text-fig. 25 b).

The antcnnulae., which extend somewhat beyond the end of the abdomen, have the segments
24 — 25 almost completely fused and the appendages like those of Gaidius tcmiispimis and Gaetanus
armiger; the Sp. segm. 23 is at least twice as long as segments 24 — 25. The segments 2, 8 o^ 9 and 20
are of about equal length and about i-i shorter than segment 19. The antennae differ from those of
Gaetanus armiger (cf. Giesbrecht p. 221) by the Re II, which is distinctly twice as long as Re I,
and has not only the second but also the third Se placed on a conical protuberance. The mandibulae
differ from G. armiger by the fairly long plumous Si i of the third basipodite and the short Se 2 with
a few branches. The maxillulae and maxillae are scarcely different from those of G. armiger (text-fig.
25 i). The third basipodite of the maxillipes is 1-3 as long as the two first segments and 3 times as
long as the endopodite; the second basipodite has almost in the middle anteriorly on the exterior
surface a laminous process with a concavity turning forwards; its tip is somewhat produced and
rounded, and proximally to it a more or less distinct tooth is found (text-figs 25 k and j). The fourth L,i
of the hasp. II has in addition to the usual sensory lobe and two hairs a small conical process repre-
senting the third hair.

The pes I has the articular line between Re I and II distinct anteriorly, except near the inner
margin; posteriorly only a faint line was observed; the pes II has the vSt, which has 25 well separated
teeth, distinctly longer than the Re III, in length almost equal to Re I— II. The hasp. II of the
fourth pair of legs (fig. 3 a) has about 25—30 stiff triangularly pointed marginal bristles, in the
main placed on the posterior surface. The number of secretory pores is completely like that of Gai-
dius^ with a pore at the base of vSe Re I in pes II.

The oral surface of the labnim is in most respects like that of G. lati/ro?is (cf. fig. sd); the
bristles in group 3 — 5 are more like spines; the transverse rows of hairs between the circular spots
of group IV, as seen in fig. 3 b, are more like Gaidius tenuispinus. The lateral outline of the labrum is
very much like that of G. brevispinus, with three small elevations; no setae were observed on the anterior
surface in front of marginal row. The lamina labialis (fig. 3 c) is smooth and of another shape than
in G. latifrons, but in other respects, except for a somewhat different arrangement of the serrulae behind
the lamina, the labial appendages etc. are similar to those of G. latifrons.

As most specimens are very pellucid the intestinal tract, especially the black hindmost portion
is generally quite distinct. It shows a characteristic structure with a large somewhat pointed coecal sac
directed towards the frontal spine, a small dorsal one opposite the wide oesophagus, and behind the
latter a gentle concavity, in which the oviducts with big eggs are placed (text-fig. 25 h).

c?. Size of specimen from Thor St. 183 (?) was 5-04 mm.; anterior division 4 mm., urosome
1-04. Wolfenden's specimen measured 4-65 mm.

The shape of the body is more slender; the anterior division is 3 times as long as wide
and almost 4 times as long as the urosome. The bifurcate rostrum is shorter and more clumsy

13*

lOo COPEPODA

than in the female; dorsally to the frontal organ the outline is first bulked; above this a concavit)-,
and beneath the frontal spine another preeminence adorned with about lo transversely placed chitinous
lines, laterally somewhat convergent, are found. The comparative length of the first four abdominal
somites and the furca is 15, 34, 23, 23 and 14; the anal somite is, seen from above, almost completely
covered, and the furcal ramus is only a little longer than wide.

The atitcufitilae (text-fig. 25 g) extend about to the end of the second abdominal somite, but
not as in the female beyond the end of the abdomen. The segmentation from segm. 8—14 is difficult
to make out, partly because the articular membranes are rather indistinct and partly because a number
of faint transverse lines were seen between the real membranes ; it seems, however, that only the segm.
12 and 13 are really fused; the segments 20 and 21 are completely, and 24 — 25 only partly fused. The
number of "^stetasken" is like Giesbrecht's description oi Actidius (Taf. 14 fig. 13), but the segments
8i>Jg possess 4. The segments 11 — 13 bear two setae each, of which the proximal is the longer, and is
inserted in a small protuberance; the Sd of segments 14, 15, 16 and 17 are placed on small protuberances.
The posterior seta of segm. 23 extends .somewhat beyond the middle of segment 24. In the Re II of the
antennae no setae were observed. The mandibulae possess a large but soft manducatory part without
distinct teeth but with a short Sdi; the Basp. 2 has an ovoid minutely granular area, and the third one
as well as Ri I has no setae; the setae of the Ri and Re are better developed than in the female.
The maxillulae are in main features like those of G. brevispinus (fig. i e) but the Basp. Ill seems
only to have a single delicate seta, and the Re only 10 setae. The inaxillac and niaxillipeds are scarcely
different from those of Gaidhis.

The pes I is more slender than in the female; the articular line between Re I — II is wanting
posteriorly; the Se Re II is represented by a very short delicate bristle; the glandular pore in the
outer margin of Re III, which is only indicated in the female, is well developed. The inner margin
of the second basipodite was found smooth not only in the fourth, but also in the third pair of legs.
The fifth pair of legs (PI. Ill figs 3 d — f) is in main features like that of Gaidius, but is as a whole
distinctly more slender. The right endopodite, which is half as long as Re I and distally and posteriorly
has a short tooth, is distally inflated and spoon-.shaped; the Re II has the anterior process which
encloses the bowel-shaped cavity shorter and more prominent (fig. 3 f). The endopodite of the left legs
is almost ^/^ of the length of the Re I; it is indistinctly divided into 3 segments, of which the second
is the shortest, and has no terminal seta. Inwards, at the base of Re III, a small process bearing 4
short hairs is found.

Y (Stage V). Size: female from Thor St. 183 (?) 4-0 mm. ; anterior division 3-2; urosonie o-8 nun.
Farran's 3'oung male measured 4-3 mm.

The relative length of the four abdominal somites and the furca is: 19, 21, 18, 19 and 17;
the furcal rami are 1-3 as long as wide. The antennulac are distinctly longer than in the adult, and
the measurements are slightly different. The maxillulae have, in contrast to the female, only 10 setae
in the Re, and the lob. IV of the second basipodite of the niaxillipeds bears 3 setae as in the male, in
addition to the sensory lobe. The articulation between Re I and II in the first j^air of legs is only
indicated anteriorly as a faint line; the St. of the Re III in the second pair of legs has only 20 teeth,
the setae along the inner margin of the basipodite of the fourth pair of legs are rather stiff. The

COPEPODA loi

male differs from the female by the presence of a fifth pair of legs which as shown in text-fig. 25 n,
is like that of Gaidius.

Y (St. IV). Size of male from Thor St. 165 was 3-29 mm.; anterior division 2-6; nrosome
0-69 mm.

The body is comparatively slender, a distinct limitation between the head and the first thoracic
tergite is observed, the somites IV and V are as in other stages fused with well marked lateral spines.
The relative length of the abdominal somites and the furca is 11, 17, 19 and 13; the furcal rami
are 1-4 as long as wide. The antennulae extend about 3 segments beyond the end of the abdomen.
Tlie maxilhtlae differ as usual by the 9 setae of Re, but the Basp. Ill has only 3 Sa + i Sp, and the
Ri I — II each 2 Sa + i Sp; the laminous process of the maxillipeds has a slightly different shape with-
out terminal tooth (text-fig. 25 1). The pes I has Re II— III fused, but Se Re II is present; the fourth
pair of legs (fig. 3 g) has like the two preceding pairs, the Re IltviIII fused, with 3 Se and 16 teeth
in the terminal seta; the secretory pore corresponding to the Se Re II is missing. The only difference
between the 2 sexes is found in the presence of a fifth pair of legs of the usual rudimentary type in
the male (text-fig. 25 o).

Y (St. III). Size of specimen Thor vSt. 167 2-48 mm.; anterior division 2-07 mm.; nrosome 0-41.
The shape of the body is distinctly more slender, and so is the frontal spine; the rostrum is

blunt; the head is as in preceding stage well separated from the first thoracic somite, but also the
fourth from the fifth one, which has no lateral spines. The relative length between the two ab-
dominal somites and the furca, which is 1-4 as long as wide, is 12, 20 and 11. l^\i^ antennulae extend
4 segments beyond the tip of the abdomen; the segments 2 — 3 and 4 — 5 seem to be fused, and the
measurements are in several respect rather different; it is curious that the segment 25, which is well
separated from the preceding one, is not only relatively but also absolutely longer than in any of the
preceding stages (it is shortest in the f$). The maxilhtlae are like those of preceding stage, but differ
by 8 setae in the Re and by the Li I, in which one of the posterior setae is wanting (only 3 present),
and one of the anterior ones (S 5) is represented by a short spine. The other mouth appendages, except
the maxillipeds which have the the laminous process rounded, are in main features like those of
preceding stages (text-fig. m).

The pes II, which like pes III — IV have the Ri unsegmented, has a fairly distinct limitation
between Re I and Re II — III, and is in main features like fig. t^^^ the pes III differs from II by less
distinct limitation between Re I and Re II ^ III, but the latter segment has only 2 Se; the pes IV
is again more reduced, as seen in fig. 3 h, as all the segments are completely fused, and as only a
single secretory pore was found.

Variation etc. A single specimen from Thor St. 152 showed a rather curious shape of the
dorsal outline behind the frontal spine; as the species was in all other respects like the rest, the
structure ought perhaps to be regarded as a kind of deformity (text-fig. 25 f).

"Sacshaped structures" like those described in G. tenuispimis are found in several specimens,
mostly adult females, but also in young ones of the penultimate stage; the following number of "para-
sites" were found in samples from the following 6 stations of Thor viz. '9/6 1904 St. 152 7 parasites in

I02 COPEPODA

f$ and I in yj", "/y 1904 St. 183 2 par. in f$ and vc?, 79 1905 St. 167 13 in f$ and 2 in y^, 9/5 1505
St. 72 15 in f$, and 14 in y^, ^9/3 1905 St. 165 i in f$ and 22/5 1^04 St. 99 i parasite in f$.

Occurrence. The Ingolf Exp. has not taken any specimens of this species, but it was gathered
in several hauls by the Thor.

In Denmark Strait:

'9/6 1904 St. 152 65°oo L. N. 28"io L. W. Yt. 1000 M. Wire 6 f ?, i y? (V), 2 yd' (V).

800 M. Wire 7 f ?.

? i5f?, 3y? (V), 12 yd' (V).

? 18 f?, 2f?(V), 10 yc? (V), 2y?(IV).

=% 1904 St. 153 65°20 L. N. 27°i2-5 L. W. Yt. 800 M. Wire i f?, 4 yc? (V).
"It 1904 St. 154 65°2o h. N. 27"io L. W. 2 f?, 2 y? (V), 2 yd' (V).

In the Atlantic south of Iceland it was gathered at the following stations.

'0/7 1904 St. 180 6i°34 h. N. i9°05 L. W. Yt. 1800 M. Wire i f?, i yd* (V).

"l-j 1904 St. 183 61=30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 39 f?, 23 f d*. 10 y? (V), 31 yd* (V), 4 y? (IV),

4yc?(iv).

25/5 1904 St. 104 62°47 Iv. N. i5°o3 L. W. Yt. 1500 M. Wire 10 f?, 4 f d*, 15 y? (V), 9 yd' (V), i y? (IV),

I yd' (IV).
East and south-east of Iceland it was gathered at 2 stations:

-/s 1904 St. 99 65°i5 I.. N. 9°53 L. W. Yt. 1700 M. Wire 3 f?, i y? (V), i y? (IV).
"/? 1903 St. 164 62°io L. N. 4°36 L. W. i f?.

South-west of the F'seroes outside the Ingolf area the species was taken at the following stations:

'5/6 1905 St. 82 5i°oo L. N. ii°43 h. W. Yt. 1200 M. Wire 2 yd" (V); 2 y? (IV), i y (III).

800 M. Wire i y? (V).
8/6 1905 St. 72 57°52 Iv. N. 9°53 L. W. Yt. 1500 M. Wire 80 f?, 5 ^c?, 36 y? (V), 83 y d" (V), 7 y? (IV),

16 yd* (IV), 2y (III).
29/8 1905 St. 195 6o°oo Iv. N. io°35 L. W. Yt. 1500 M. Wire 5 f?, i y? (V).
V9 1905 St. 167 57°46 L. N. 9°55 L. W. Yt. 1500 M. Wire 46 f ?, 12 y? (V), 13 yd' (V), 5 yd" (IV), 4 Y (HI).

Distribution and Remarks. I have examined specimens of this species which were determined
G. Kriippi Giesbr. by Professor Sar.s. G. Knippi G'leshr. differs from my specimens by the much
smaller size ($: 3'6~4 mm.; d": 37 mm.), and on that account I am not quite sure that they are iden-
tical. I have on that account at a earlier date preferred the name G. major Wolf., and this name is
printed on Plate III. But as the description of G. Kruppi was published a few months previous to
that of G. major (as stated by A. Scott), and as Wolfenden not only in his original description (1903
p. 114) says "the lamellar appendage of the posterior foot-jaw is absent", but reiterates the same state-
ment as late as 191 1 (p. 231), well aware of the importance of this character, I feel obliged to accept
the name G. Kruppi at present. As Wolfenden has identified drawings of specimens from the
west coast of Ireland which were submitted to him by Farran as belonging to G. major^ and as
Farran (1908), about the species which he names G. major Wolf., writes "G^. Kruppi appears to be at

COPEPODA 103

most a rather smaller Mediterranean variety of this species", it seems probable that Farran's spec-
imens belong to the species described above. The female of which A. Scott in the Siboga Expe-
dition has given figures and has identified with G. Krnppi\ is possibly identical with this species
(Size 57 mm.; lobe IV maxillipeds with 3 setae and frontal sj^ine rather short), but the male is scarcely
so on account of the different shape of Re dextr. pes V. Scott regards Esterly's G. brcvicornis (1906
p. 56—57) as identical with G. Kruppi^ though the lamella of the maxillipeds has quite another shape, and
his G. clams (pp. 57—58) as the male of this species ; in the latter supposition he is possibly right,
but it is in any case different from the male from the Atlantic.

If G. Kntppi and major of the different authors are identical, its distribution is wide (Indian
Ocean, South and North Atlantic and the Mediterranean); if only the localities which certainly belong
to the species described here are taken into consideration its range encompasses the North East
Atlantic as far south as 50° L,. N. and as far north as 65° L. N.; it is distributed as far west as
Denmark Strait (L. W. 28°), and as far east as the Fseroe-Iceland channel (I^. W. 4°). All records show
that it is a deep sea species.

26. Gaetanus minor Farran.
(PI. Ill fig. 4a).

1905. Gaetanus minor n. sp. Farran, p. 34, pi. V figs 1 — ii.

igo6. — — Farran. Pearson, p. 14.

1908. — — — Farran, p. 37.

1908. — — — V. Bremen, p. 41, fig. 46.

190S. — — — Wolfenden, p. 32.

1909 Gaetanus minor Farran. A. Scott, pp. 47— 48, pi. IX

figs 1—8.
igii. — — — (minimus? n. sp.) Wolfenden,

pp. 233- 234, text-figs 20 a— e.

Description. f$. Size: 2-3 mm., anterior division 1-89; urosome 0-44 mm. Farran's specimens

measured 2'4 mm.

The short rostrum is undivided. The anterior division is 4-3 as long as the urosome. The
lateral spines reach the end of the genital somite (fig. 4 a). The genital somite is rather swollen below,
with a distinct receptaculum seminis. The caudal rami are almost as long as wide. The relative
length of the abdominal somites and the furca is 20, 9, 8, 8 and 7.

The antennulae reach just beyond the end of the genital somite; the measurements are prac-
tically as given by Farran, and the appendages are as in preceding species. The Re of the antennae
is scarcely 1-4 as long as Ri; the Ri I is twice as long as Re II, which is again 2-6 as long as Re I,
and 1-6 shorter than Re III. The Re II has the short Se 2 placed on a conical protuberance, but has
none for the more slender Se 3. The maxillulae differ from those of G. Kruppi by the 2 spinelike
Sp. of the Li 2. The third basipodite of the maxillipeds is ri as long as the 2 first, and 27 as long
as the Ri; the second basipodite has, as stated by Wolfenden, a rounded lamellous process, and the
lobe IV has as usual 3 setae + a sensory lobe; the third basipodite has in a similar way as in G. miles
Giesbr. (cf. Taf. 14 fig. 24) the inner margin produced into a rounded process which slopes most
gradually towards the base, and here bears the usual row of teeth. This process is distinct but nnich
lower in G. Kruppi, and is only indicated in Gaidiiis.

The terminal seta in the exopodite of pes II, which has 14 well separated teeth, is ri as
long as the Re I— II. The second basipodite in the fourth pair of legs has 12 stiff pointed bristles

I04

COPEPODA

of the usual structure. The secretory pore at the base of Se Re I is wanting in pes II, present in
III -IV.

Occurrence. The Thor has gathered a single adult female 2°/,, 1904 St. 88 48°og L. N. 8°30
L. W. Yt 300 M. Wire. This species has been recorded from the west coast of Ireland from a depth
of about 400 fathoms, from the middle of the South Atlantic between 5° L,. N. and 30' L. S. and from
the Malay Archipelagos.

Though Far ran does not mention the process of the Re II of the antennae nor the lamellous
process of the maxillipeds, I do not doubt that the described species is identical with his G. minor] the
mentioned features are found in Wolf end en's species, which he somewhat prematurely proposed to
name G. minimus, if it should turn out to be another species than G. viiiior\ the only difference between
Wolfendens specimens and mine is the somewhat shorter antennulae, which do not extend beyond
the end of the genital somite, and the smaller size (175 — 2 mm.). Between my specimen and Scott's
description of specimens from the Siboga Expedition no difference except the shorter antennules of
the females from the Siboga Expedition was found.

27. Gaetanus pileatus Farran.

(PI. Ill fig. 6 a; text-figs 26a— e).

1903. Gaetanus pileatus n. sp. Fanan p. 16, pi. XVII figs i — 11. I 1908. Gaetanus c.-iudani Cauu. v. Bremen, p. 42, fig. 48,

1904. — caudani Canu. Wolfenden, p. 114, pi. IX, figs [ 1908. — pileatus Farr. Farran, pp-35— 36.

20-22.

1905. — pileatus Farr, Farran, p. 33.

1905. — caudani Cauu. G. O. Sars, p. 4.

1906. — — — Pearson, p. 13.
1908? — — — Wolfenden, p. 31.

1909. — caudani Cauu. A. Scott, pp. 46 — 47, pi. VI 11

figs 9-- 1 5.
1911. — pileatus Farr. Wolfenden, pp. 229 — 231, taf, 27

figs. 1—2, textf. 17 a— c.

Description. f$. Size: Specimen from St. 82 measured 574 mm.; anterior division (including
frontal spine 04 mm.) 47; urosome 1-04 mm.

The frontal spine has, as seen in (text-fig. 26 a) and as described by the authors, a very charac-
teristic shape; the frontal organ is rather indistinct; the rostrum, which is very short, is in some spec-
imens undivided, in others terminally slightly bifurcate. The fourth and fifth thoracic somites show
dorsally trace of segmentation. The lateral spines are rather suddenly produced, slightly divergent,
and almost reach the end of the genital somite. The anterior division is distinctly 4 times as long as
the urosome, the genital somite is distinctly produced below, and the structure of the receptaculum
etc. is in lateral view like that of G. lati/rons (cf. fig. 5 b).

The relative length of the abdominal somites and the caudal rami, which are almost as long
as wide, is 42, 23, 19, 19 and 20.

The antennulae extend 6—7 segments beyond the end of the abdomen. The measurements
provide some similarity to Gaetanus miles, but differ especially by the more slender distal segments;
the segment 19, which is the longest segment, is twice as long as segment 2, 17 as long as segments
8<>i9 and 1-2 as long as segment 22; the segment 19 is 23 as long as segment 24. In the antennae
the Re is only i-i as long as Ri, and the Ri I is 2-5 as long as Re II, which only possesses a terminal
seta, and is only a trifle shorter than the Re VII. The inaxillulae possess no spinules on the posterior

COPEPODA

105

surface of Li i, but has about 14 fairly stroug spinules on the anterior surface of Li III. The third
basipodite of the maxiUipeds is i-i as long as the two first ones and 28 as long as the Ri; the exterior
margin of the second basipodite bears a fairly slender rounded lamella (text-fig. 26 d) and the fourth
lobe is divided most distinctly by a deep cleft into a posterior • ''

smooth division and an anterior one, which possesses 3 setae
in addition to the sensory lobe.

The Re I— II of the first pair of legs are completely
fused with the exception of a small lateral incision. The ter-
minal seta of the second pair of legs has 19 teeth, and is dis-
tinctly longer than the Re III. The second basipodite of the
fourth pair of legs has 20 lamellous bristles. The secre-
tory pore of Re I is wanting in pes II, present in III — IV.

The labritm is anteriorly scarcely different from that
of the preceding species; orally it is as seen in fig. 6 a in main
features like G. ICntfipi (V\. Ill fig. 2e); the longitudinal series has
in most groups two or more rows of hairs. The transverse groups
of short hairs around the median circular spot Nr. 4 are on each
side dissolved into a somewhat triangular group as seen in fig.
6 a, and somewhat behind it a transverse area of short spines
or granules is found.

The laiiiiiia lahmlis is like that of fig. 5 e but is almost
smooth; in front of this we have the usual two lateral series
of slender spines, of which the more lateral is almost semi-
circular, while the median one is very short. In front, by a smooth
area separated from the lamina, a wide area covered with flat
granules and almost fused with the corresponding part of the
other side is found. The 4 transverse groups of densely placed
short spines behind the lamina are like those of G. Kncppt {i\g. 3 c).
The lateral longitudinal series shows the following structure:
Sen N r. I consists of 10 short hairs in a transverse group and
of 30 in a longitudinal group, continued upon the lobus labialis
and partly confluent with the series Nr. 2, which has 20 slender hairs placed longitudinally. The
series Nr. 3 has two groups behind, of which the more lateral is more posterior (in contrast to fig. jf
PI. II), and a longitudinal row which on the posterior surface of the lobus labialis is continued to
near the tip. The series Nr. 4 is posteriorly placed almost transversely, forming a convexity, turning
backwards and almost reaching corresponding part of opposite side, and is anteriorly continued to tip
of the lobus labialis. The series Nr. 5 consists of a median transverse group of about 30 longer and
shorter setae placed near the middle, and a more lateral partly longitudinal group; this group is
not continued directly into any series on the labial lobe, but probably corresponds to the most medial
one which is dissolved into independent groups. Possibly the series 5 corresponds also to the longitu-

The Ingolf-Expedition. III. 4. ^

Text-fig. 26. Gactanus pileatus Farr.

a. f9. Head X i8.

b. f9. Right caudal ramus in abnormal spec-

imen X .57.

c. f9. Maxillipes sin in anterior view X 57-

d. y d" (Stage V) m. s. in ant. view X 57-

e. y c? (Stage V) pes V in anterior view X 57-

I06 COPEPODA

dinal group medially to the seirula 6-dentata and the inner series in front of the lamina (cf. PI. II fig.
yf s 6); if this interpretation is right, the serrula 6-dentata (fig. 7 f s 7) perhaps corresponds to Sen 4.

Y^ (Stage V). Size of female from Thor St. 82 was 574, anterior division 4-2 mm., urosome 0-87.

The relative length of the abdominal somites and the fnrcal rami, which are about i-2 as
long as wide, is 20, 23, 18, 20 and 17. The appendages show similar differences from those in the
adult as G. Kruppi] the lamina of the second basipodite of the maxillipeds is shorter and more rounded
(text-fig. 26 d); but the inner margin of basip. II pes IV is smooth; the fifth pair of legs is in main
features like those of G. Kritppi (text-fig. 26 e). In contrast to Canu's description of a young male of
G. caudaiii the Re I — II of pes I are completely fused without Se Re I.

Y ^ (St. IV). Size of a male from Thor St. 82 was 372 mm., anterior division 3-01 mm., urosome
071 mm.; a female measured 3-5 mm.

The relative length of the abdominal somites and furca was 19, 18, 24 and 13. The anten-
nulae extend at least 8 segments beyond the end of the abdomen; the differences in the other appen-
dages are scarcely different from those described in Gactanus Kriippi.

Parasites and Abnormity. Sac-shaped parasites like those described in G. tenuispinns were found
in one specimen from Thor St. 78 and 99, in 5 from Thor St 183, in 28 adult females from Thor
St. 82 (Yt. 1200 M. W.) and in 60 from St. 72. In a single adult female the setae of the right caudal
ramus was branched (text-fig. 26 b).

Occurrence. The Ingolf Expedition has not gathered this .species, but it has been captured at
the following stations by the S/S Thor in Denmark Strait.

'9/6 1904 St. 152 65°oo L. N. 28°io L. W. Yt. 1000 M. W. i y ? (V).

? 8 f?.

^% 1904 St. 153 65°2o L. N. 27°i2-5 L. W. 5 f?, i yd" (V).

^■/fi 1904 St. 154 65°27 L. N. 27°io L. W. i f?, i yd* (V).

In the Atlantic south of Iceland.

'V7 1903 St. 164 62°io L. N. i9°36 L. W. i yd" (IV).

■■/7 1904 SL 183 6i°30 L. N. i7"o8 L. W. Yt. 1800 M. Wire 19 f?, i yd* (V).

24/5 1904 St. 104 62°47 L. N. i5°o3 L. W. Yt. 1500 M. Wire 34 f?, i yd* (V).

Vg 1904 St. 286 6i°49 L. N. i4°ii L. W. Yt. 800 M. Wire 3 f?, i y? (V).

In the Iceland-Fseroe channel.

'2/5 1904 St. 78 6i°7 L. N. 9°3o L. W. 3 f ?.
"A 1904 St. 99 6i°i5 I.. N. 9°35 L. W. 7 f ?■

In the Atlantic, south-west of the Faeroes.

'5/6 1905 St. 82 5i°oo L. N. ii°43 Iv. W. Yt. 1200 M. Wire 2701?, 38y? (V), 15 yd* (V), 3 y? (IV), i yd" (IV).

Yt. 800 M. Wire 40 f ?, 4 y? (V), 3 yd" (V).
76 1905 St. 72 57°52 L. N. 9°53 L. W. Yt. 1500 M. Wire 180 f?, 23 y ? (V), i yd" (V), i yd" (IV).
"/s 1905 St. 165 6o°oo L. N. io°35 L. W. Yt. 1500 M. Wire i f?, i y<? (V).
^°/6 1905 St. 88 48°09 L. N. 8=30 L. W. Yt. 300 M. Wire 2 f ?.

COPEPODA

107

Distribution. About this species Far ran writes (1908 p. 36) "this species is a very noticeable
feature in the deep-water fauna off the west coast of Ireland, occurring often in considerable numbers,
in almost every tow-net from 200 to 1150 fathoms".

The gatherings of the Thor seem to show that it is much more abundant south of 60° L. N.
even if it is found in Denmark Strait as far north as 65° L,. N. By Wolfenden it has been
recorded from the South Atlantic, and it was found by the Monaco Expedition, as well as at 5 stations
from the deep water of the Malay Achipelago (5 females only).

Remarks. Though I have not seen Farran's original description, I am quite sure that my
species is identical with his G.pilcatus and different from Canu's G. caudani (if this author has not
examined an abnormal specimen). As I have examined specimens determined by Sars as G. caudani^
no doubts exist 'about its identification with the Monaco's species; and the same is the case with
Wolf end en's species, from the South Atlantic. As the lamina of the maxillipeds (PI. VIII fig. 13)
was differently shaped in the Siboga specimens (length 57 mm.), I am not quite convinced of Scott's
identification. Scott regards Esterly's G. unicoruis as identical with his G. caudani, which he
regards as the synonym of G. pilcafns, but he is scarcely right, as the lamina of the maxillipeds
has quite another shape in Esterly's species (1906 PI. XII fig. 54).

28. Gaetanus miles Giesbrecht.
(PI. Ill figs 7 a— b).

1 888. Gaetanus miles n. sp. Giesbrecht, p. 335.

1893, — — Giesbr. Giesbrecht, p. 219, taf. 14 & 36.

1895. — — — Giesbrecht, p. 248.

1898. — — — Giesbrecht & vSchmeil, p. 32.

1903. — — — Norman, p. 136.

1903. — — — J. C. Thomsen, p. 17.

1904. — — — Cleve, p. 191.

1905. Gaetanus miles Giesbr. G. O. Sars, p. 3.

igo6. — — — Pearson, p. 14.

190S. — — — Farran, p. 36.

1908. --- — — V. Bremen, p. 39, fig. 42.

1909. — — — A.Scott, pp.44— 45, pi. Vlll figs

1—8

1913. — — — Wolfenden, p. 231.

Description, f $. Size of specimen from Thor St. 82 was 4-21 mm.; anterior division 3-4, urosome
o-8i mm. Giesbrecht's specimen measured 3-5, Scott's 4-3 and Wolfenden's 3 mm.

The shape of the body is scarcely different from Giesbrecht's figure; the anterior division
is 4-2 as long as the urosome, which has the relative length of the somites and furcal rami as
follows: 34, 13, II, II, 15; the furcal rami are 1-3 as long as wide. The anienmtiac diiier irom those of
Giesbrecht's specimen by the proportional length of the segments; the segment 19 is a Httle longer
than 22, which is the longest according to Giesbrecht, and this again is a Httle longer than
20; the segments So^c), 13 and 24^25 are in G. miles of almost equal length, but in my specimens
segment 13 is i-i as long as 8 cn; 9 and i-2 as long as 24 0= 25. The mouth-appendages, with the excep-
tion of the maxillipeds, are scarcely different from those of G. miles; in this pair of appendages the
third basipodite is 3 times as long as the endopodite, and i'3 as long as the Basp. I— II; the plate-
shaped process of the exterior surface of the second basipodite is rounded and almost semicircular
(fig. 7a), and distinctly different from Giesbrecht's fig. 24. Taf 14. In the first pair of legs the
articular line between Re I — II was scarcely indicated; the Ri of the second pair of legs has the
articulation between Ri I— II fairly distinct anteriorly, and scarcely indicated posteriorly; the second basi-

14*

I08 COPEPODA

podite of the fourth pair of legs possesses 15 strong knife-shaped spines (PL III fig. 7 b). The glan-
dular pore at the base of Se Re I is wanting in the second pair of legs but found in pes III — IV.

The oral surface of the labni»i is in the main like that of G. pileatus (cf. fig. 6a PI. Ill);
the first group in the longitudinal series consists of numerous short setae (2—3 setae deep), and
the second of somewhat longer ones; in the third group only a single row of fairly long spines
were observed, and in the third one a few very short ones w-ere observed laterally in addition to the
inner row of long knife-shaped spines (cf. fig. 5 d). The la?nina labialis is smooth as in G. Kruppi^
but the area in front of and behind it is like that of G. latifroiis.

Y$ (St. V). Size of female from St. 88 3-34 mm.; anterior division 276 mm., urosome 0-58.

The relative length of abdominal somites and fuvcal ramus, which is i-i as long as wide, is
15, 13, 9, 12 and II. The measurements of the anteunulae are more like those of the G. milcs^ as
segment 22 is a little longer than 19, and as segments 8 cnj 9, 13 and 24 c^ 25 are of almost equal length.
In other respects of anj- importance the appendages are scarcely different from those of the adults,
except by the structure of the second basipodite in the fourth pair of legs, which is smooth and has
the inner margin almost straight, not suddenly produced as seen in fig. 7 b.

Occurrence. The Ingolf Expedition has not taken this species, but the Thor has gathered a
few specimens at four stations viz.

"/; 1904. St. 183. 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire i f ?.

'% 1904. St. 180. 6i°34 L. N. i9°05 L. W. Yt. 400 M. Wire i f ?.

'5/6 1905. St. 82. 5i°oo L. N. ii°43 L. W. Yt. 1200 M. Wire i f?.

^0/61905. St. 88. 48°o9L. N. 8=30 L. W. Yt. 300 M. Wire i y?.

Distribution. This species has previousl)- been recorded from the west coast of Ireland, from
the area explored by the Monaco Expedition, from the South Atlantic between 20 and 40 L,. S., from
the JMalay Archipelagos and from the Pacific (3° L. S.— 5° L. N. 99°— 115° L. W.).

Remarks. I am not quite sure that the specimens which I have examined really are iden-
tical with Giesbrecht's G. miles, which is smaller, has the relative measurements of the anteu-
nulae somewhat different, the lamina of the second basipodite of the maxillipeds quite differently
shaped and only 5 instead of 15 spines marginally in the second basipodite of the fourth pair of legs.
Scott's specimens agree with mine in the number of the mentioned spines, in the size and partly in
the shape of the lamina of the maxillipeds, but differ in the measurements of the antennulae. As
Scott's specimens form a connecting link between Giesbrecht's and the Atlantic specimens, I do
not think the establishment of a new species is warranted.

29. Gaetanus latifrons G. O. Sars.
(PI. Ill figs 5 a — g; text-figs 27 a— e).

1905. Gaetanus latifrons n. sp. G. O. Sars, p. 1 1.
1905. — holti u. sp. Farran. pp. 33 — 34, pi. VI figs

I — 12.

1905. — longispinus u. sp. Wolfeuden, pp. 7 — S, pi. III.

1906. — latifrons G. O Sars. Pearson, p. 14.
1908. ^ ^ ^- Farran, p. 36.

1908. Gaetanus latifrons G. O. Sars. v. Bremen, p. 39, fig. 43.

1908. — holti Farran. Wolfenden, p. 31.

1909. — — — A. Scott, pp. 49—50, pi. X figs

10-17.
1911. — — — Wolfenden, pp. 232 — 233, fig. 19.

COPEPODA

109

Description, f^?. Size of specimen from Thor St 183 was 5-1 mm.; anterior division 4 mm.;
urosome 11 mm. Sars' specimens measured 4-85 mm., Farran's specimens 5-1, Scott's 5-4 and
Wolfenden's 37 — 4 mm.

The frontal spine, which has a triangular base, has as seen in fig. 5 a the tip directed forwards
and upwards. The distance between the base of the frontal spine and the frontal organs, which are
placed on a small process, is almost straight with a low crest The rostrum is terminally bifurcate.
The shape of the body is scarcely different from Farran's figure; the anterior division is 2-^ as long
as wide and 3-6 as long as the urosome. The genital somite (fig. 5 b), which is distinctly 1-4 as wide
as long and i"i as deep as long, has a fairly prominent receptaculum semiuis. The relative length of
the abdominal somites and the furcal rami is the following: 42, 23, 19, 18 and 21; the furcal rami are
I'l as long as wide.

The atitcnnae, which have the Re about 1-3 as long as the Ri, have the Ri I almost twice as
long as Re II, which is 17 as long as Re I, and a little shorter than Re VII. The Re I has a single
terminal seta on a conical protuberance, and the Re II
has 3 setae, of wliich the basal is the longest and
like the median one is placed on small protuberances.
The maxillulae possess 5 setae on Li II; the Li I has
no spinules posteriorly and the Li III has none ante-
riorly. The third basipodite of the inaxillipcds is 3
times as long as the endopodite and 1-3 as long as
the first and second basipodites combined ; the lamina
of the second basipodite (te.xt-fig. 26 b), which is folded
in a characteristic way, is in the whole length faste-
ned to the anterior surface of the segment; the inner
margin of the third basipodite is basally not straight
as shown in Farran's figure, but slightly convex as
figured by Scott

The first pair of legs has a well developed
articulation between Re I and II, and the Se of Re II
almost reaches the end of Re II. The second pair of
legs has a well developed articulation between Re I and II, and a glandular pore at the base of Se
Re I; the terminal seta, which has 23 teeth, is a little longer than the Re III, and of equal length
to Re I— II.

The second basipodite in the fourth pair of legs has about 25 knife-shaped spines as shown
in fig. 5 c.

The oral surface of the labruni is fairly characteristic, as shown in fig. 5 d, especially the trans-
verse rows of granules around the median circular spot Nr. 4; the lamina labialis has a characteristic
granulation as seen in fig. 5 e, which also illustrates the area in front of it The arrangement of setae
in the lateral series behind the lamina labialis is not unlike that of G. pileatus: Ser. set i consists
of about 70 short setae placed in a longitudinal group: The series 2 seems to be represented by 3

Text-fig. 27. Gaetatiiis latifrons G. O. Sars.
a. f9. Maxilla sin in post, view X 57- b. f9. Maxillipes
sin. in ant. view X 57- c. Y (stage IIIj. Maxilla dext. in
ant. view X 57- d. Y (stage III). Maxillipes sin. in an-
terior view X 57- e. Yd" (stage V,i. Pes V in anterior
view X 57-

no COPEPODA

groups with from lo — 25 slender setae, of which the first is placed behind near the middle, while the
third, which is more longitudinal, is j^laced laterally more in front. The series Nr. 5, to which the two
most medial groups mentioned ought perhaps to be referred, falls in this species naturally into three
divisions, forming together an outwards convex figure (like that in fig. 7 f PI. II) consisting of 2 hairs
most medially, well separated from the group of 14 hairs, which is almost fused with the dense longi-
tudinal row almost reaching the end of the labial lobes; the series Nr. 3 — 4 are scarcely different from
those of G. brevispintis (PI. II fig. 7 f).

Y^ (St. V). Size of female from Thor St. 183 was 4-16 mm.; anterior division 3-29 mm.;
urosome 0-87.

There is indication of an articular line between head and first thoracic tergite, and between the
fourth and fifth ones. The relative length of the abdominal somites and the furcal rami, which are
1-2 as long as wide, is the following: 19, ig, 17, 19 and 17. The first abdominal somite is somewhat
produced below, more so than in the male. The inner margin of the second basipodite is in both sexes
almost straight, and distinctly different from that described in the adult female; in the female we find
about 20 stiff pointed setae, and in the male about 9 setae of usual structure (in pes II a close row of
20 is observed). The fifth j^air of legs is very similar to that of G. Kruppi (text-fig. 27 e).

Yq (St. IV). Size of female from Thor St. 183 was 3-13 mm.; anterior division 253 mm.;
urosome 060. A male measured 3-45 mm.

The relative length of the abdominal somites and the furca is as follows 15, 18, 19 and 13.
The antennulac extend by at least 2 segments beyond the end of the abdomen. The maxillulac
show differences corresponding to those described in G. Kruppi. The lamina of the maxillipeds
has a less complicated structure, is more prominent and of obtusely triangular shape. The pes I has
the Re I — II fairly well separated, and has 3 Se pes I; the second basipodite of the fourth pair of
legs has only 3 — 4 setae along the inner margin. The only difference between the male and female
is found in the presence of a fifth pair of legs (cf. text-fig. 27 o).

Y (St. III). Size of specimen from St. 82 was 248; anterior division 2*04; urosome 0-44 mm.

The head and the first thoracic somite as well as the fourth and fifth ones are well separated.
The frontal spine is scarcely different from that of the adult females, but the lateral corners of the
thorax are rounded without trace of spines. The relative length of the abdominal somites and the
furca is 15, 18 and 9. The antennulac^ which extend 3 segments beyond the end of the ab-
domen, show similar differences from those of the adult ones as in G. Kruppi. The iiiaxillulae have
only 8 setae in Le, but in other respects show similar differences as in preceding; the Li II possesses
5 setae as in the adult females. The exterior margin of the maxillae (text-fig. 27 c) is almost straight,
in contrast to the structure in the adult females, the structures in the two preceding stages forming
intermediary steps. The lamina of the maxillipeds is more regularly rounded and apparently more
prominent (text-fig. 27 d).

In the first pair of legs the segmentation of the exopodite is only indicated laterally; 3 Se are
present, but the two proximal ones are very short; the 3 last pair of legs are scarcely different from
those of G. Kruppi.

COPEPODA III

Variations etc. In a single young female of stage V the third seta of the left caudal rami
was dichotomous.

Sac-shaped "parasits" like those described in G. tenuispinus were found in four adult females
and in a young male from St. 183.

Occurrence. The Ingolf Exp. has not taken this species, the S/S Thor has gathered it at the fol-
lowing stations.

19/6 1904 St. 152 65^00 L. N. 28°io L. W. I y? (V).

"/y 1904 St. 183 6i°30 L. N. 17-^08 L. W. Yt. 1800 M. Wire 8 f?, 2 y? (V), 5 yc? (V).

"/s 1904 St. 99 6i°i5 Iv. N. 9°36 L. W. if?.

'5/6 1905 St. 82 5i°oo L. N. ii°43 L. W. Yt. 1200 M. Wire i y (III).

8/6 1905 St. 72 57°52 Iv. N. 9°53 L. W. Yt. 1500 M. Wire i f?, SY? (V), \y S (V), i y? (IV), i y<? (IV).

31/8 1905 St. 167 57=46 L. N. 9°55 L. W. Yt. 1500 M. Wire i yc? (V), i y? (IV).

Distribution. The species has been taken at several stations by the Monaco Expedition, and
is fairly common on the west coast of Ireland "at depths of from 330 to 1150 fathoms". According to
Wolfenden it is "anschinen im Atlantischen Ocean sehr haufig, erscheint von dort auch in den
Fangen des "Gauss" und erstreckt sich nach Norden bis zur Westkiiste Gronlands". A single spec-
imen has by been collected the Siboga Exp. in the Malay Archipelago.

Remarks. Between this species and Sars' description of G. lafifrons scarcely any difference
was found; in .spite of some small differences, enumerated above, it is certainly identical with Farran's
G. holti\ Wolfe n den's specimens were as a whole somewhat smaller, but in other respects scarcely
different. This species seems to differ from Scott's description by the shorter antennulae and the
different shape of the lamina of the maxilliped.s.

30. Gaetanus ferox n. sj).
(Text-figs 28 a— b).

Description, i^. Size: 3-4 mm., anterior division 2-6 mm.; urosome 078 mm.

The shape of the body is most like that of Gaidius tenuispinus^ but the head dorsally terminates
in a proniinent, obtusely rounded keel (partly broken in the examined specimen). Below the frontal
spine the outline is almost straight, and is then convex towards the base of the clumsy rostrum, which
possesses two terminal points (text-fig. 28 a). The head and the first somite as well as the two last
thoracic ones are completely fused; the lateral corners are regularly rounded, but somewhat in front
of the margin are seen rather short slender spines, which probably only extend slightly beyond margin
(broken in examined specimen). The anterior division is 3-3 as long as the abdomen, which as usual
consists of 5 somites; the second somite is 1-5 as long as the third, which is a little longer than the first
and fourth; the fifth somite is just vi-sible from above. The genital pore is found on the left side. The
furcal rami are almost as long as wide; the St. 2 is somewhat longer than the abdomen (text-fig. 24 b).

The antennulae extend distinctly beyond the end of the abdomen; the segments 20—21 are
completely fused, and the segment 22 has, at least on the left side, a characteristic structure, as it is
widened out from the narrower middle portion towards the base as well as towards the tip.

112

COPEPODA

The measurements and appendages differ scarcely from those of G. Krtippi. The antennae are
like those of G. Kruppi, bnt the two branches are almost of same length. The viandibulae^ maxillulae
and maxillae are scarcely different from those of G. Kruppi. The third segment of the maxillipeds is
1-2 as long as the first and second combined, and 27 as long as the endopodite, but in other respects
this pair of appendages is scarcely different from those of G. Kriippi.

The first pair of legs is like that of Gaidius brevispinus (PI. Ill fig. i g), but the articular line
between Re I — II is indicated anteriorly, though wanting posteriorly; the Se of Re I and II are wanting.
The Se of Ri I of the pes II is wanting; the St, which has about 30 teeth, is a little longer than Re
III, which is again a little longer than the Re I — II; no glandular pore is found at the base of Se
Re I. The pes III — IV have a secretory pore at the base of Se Re 1; the basipodite of the third pair
has a marginal row of setae, but that of the fourth pair is completely smooth. The fi/t/i pair of legs
(text-fig. 28b) is in most features like that of Gaet. Kruppi (PL III fig. 3d); the right leg is

less slender, especially the third basipodite, which
is, however, less clumsy than in G. brevispiinis (PI.
Ill fig. I h); the first segment of the right exopodite
has exteriorly a slight concavity almost in the
middle and, proximally to it, a slender seta (Se Re I),
thus indicating that this segment really corresponds
to Re IcNill; the Re III differs from that of G.
Kruppi by the structure of the terminal portion
(that distal to inner process) which is only two thirds
as long as the basal part and not in the least as long
as, and, proximally to a hair-shaped terminal j^art, has
an inner lamina in the distal half. The right endopo-
dite when observed from behind, is almost completely
like that of 6". Krnppi (fig. 3d), but viewed anteriorly it is seen to have a very characteristic form on
account of a wide deep "cavity"? and a terminal tooth not unlike a Prussian helmet, but with a prolon-
gation towards the base, as if to give protection to the back of the neck. The pes V sin has the Ri
of a similar shape as in G. Kruppi^ but it is comparatively shorter, reaching only slightly beyond the
middle of Re I, and has the segmentation more indistinct; the first segment of the exopodite has the
outer margin somewhat convex, and is terminally somewhat produced inwards; the Re III, which is
scarcely I'l as long as Re II, has a fairly long terminal spine, near the base of which a delicate
seta is observed, as well as some hairy spots.

Remarks etc. Of this species I have only examined a single male, brought home by the S/S
Thor, and taken % 1905 57°52 L. N. 9=53 L. W. Yt. 1500 M. Wire.

As except in the shape of the forehead it is in almost all characters like the male of G.
Kruppi^ I think it is rightly referred to Gaetaiius. It is certainly not the male of any of the species
of Gactanus which has been mentioned in this paper; nothing indicates that it is the male of any
of the described species of Gaidius or Gaetamis.

Text-fig. 28. Gaetanus ferox n. sp.

a. Head from the left X c. 40.

b. Abdomen X c. 40.

COPEPODA

"3

31. Euchirella rostrata Clans.
(PI. IV figs I a— h; text-figs 29 a— k).'

i865. Undiua rostrata n. sp. Claus, p. n, taf. I fig. 2.
1883.? EuchiEte hessii n. sp. Brady, p. 63, pi. XX figs i — 13.
1892. Euchirella rostrata Claus. Giesbrecht, p. 232, taf. 15.

1S98.

1900.?

1902.?

1903. Nee.

1903.

1903.

1904.

Giesbrecht & Schmeil, p. 36.
Cleve, p. 4, pi. 2 figs r — 12.
Wolfendeu, p. 367.
Thompson c& Scott, p. 244.
Norman, p. 137.
J. C. Thompson, p. 18.
Wolfenden, p. 129.

1905. Euchirella rostrata

Claus. G. 0 Sars, p. 4.

1905-

— —

— Th. Scott, p. 223.

1905.

—

— Esterh-, pp. 152—153.

1905. Nee.

— —

var. magna Wolfenden, p. iS.

1905.

— —

— Farran, p. 36.

1906.

— —

— Pearson, p. 15.

1 90S.

— —

— Farran, p. 38.

1908

— —

— V. Bremen, p. 47, fig. 52.

1911.

— —

— Wolfenden, p. 235.

1912.

— —

— Esterly, p. 311.

f St. iq

measured a

L-O

7 mm. ; anterior division

nrosome o-8i mm. The size of specimens from other stations varied from 3-25 — 4-2 mm. Giesbrecht's
specimens measured 2'95— 3"i mm., Farrans 3-3 — 4-2 and Wolfendens from 2—3 mm.

Text-fig. 29. Euchirella rostrata Claus.

a. f?. Abdomen X 45- b. fcf. Rostrum X 45. c. fd"- Abdomen X 45- d- f cf- Tips of pes V from the right X 150.

e. ycT (St. V). Abdomen X 45- f- y <S (St. V) Pes V X 60. g. yd (St. IV) Pes V X 60. h. f9. Body X 33-

i-j. yQ-d- (St. V) X 33- k. f dP X 33-

The long and pointed rostrum is more vertical and the head is much more suddenly raised
than seen in Giesbrecht's fig. 23 (Taf. 36) (text-fig. 29 h). The genital somite has the ventral pro-
tuberance more regularly raised, especially behind, than shown in Giesbrecht's fig. 17 (text-fig. 29a).

The antennulae differ from Giesbrecht's description by the comparatively longer segment
2, which is almost as long as segments Scs^g. The maxillulae differ from Giesbrecht's description
(fig. 28) by one instead of 2 delicate Sa in Li 2, and by the presence of a posterior process bearing two
rudimentary setae (?) on the \Ji 3 in addition to the two well developed Sa. The sensory conical process
of Lob. IV of the second basipodite of the maxillipeds is rather small.

The pes I is completely like Giesbrech's fig. 11 (Taf. 15); the Re III has a minute pore in
the outer margin, somewhat posteriorly, and nearer the base than the tip. The pes II, which has 22 teeth
in the terminal setae, has the systems of glands of the Re well developed, in a similar way as figured

The Ingolf-Expedition, HI. 4 ^

114 COPEPODA

by Giesbrecht (fig. 27); the pores are placed on small rounded elevations somewhat removed from the
margin; the Re I has no pore, the Re II has one near the base of Se and the Re III has 2, placed at
the base of Se 1 and Se III ; the Ri III possesses a minute pore near tip on the anterior surface.

The pes III — /J^ have, in addition to the mentioned pore, one near the base of Se Re I; the
pes IV is like Giesbrecht's fig. 27, except for the somewhat different shape of the glands and the
different number and arrangement of the spines on the inner margin of the second basipodite. In one
specimen (PI. 4 fig. la) 7 triangular lamellae were observed, decreasing in size distally and posteriorly;
the seventh is placed on the hinder surface; in addition to these, 3 quite rudimentary teeth were found;
in no specimen was the number of spines greater, in several it was smaller, and sometimes almost com-
pletely like Giesbrecht's fig.; the arrangement is not always symmetrical.

The area behind the rostrum is almost straight; separated from this by a transverse groove
the labrum proper, which consists of a convex anterior portion by a shallow groove, separated from
the projecting free hinder margin adorned with two series of bristles; no bristles were observed in
front of the free margin.

The oral surface (PI. IV fig. i b) shows a very characteristic structure. In front of the first central
circular spot is a transverse row of minute granules; behind the spot I a transversely placed group of
spinules is found, probably formed by the fused yfrj/ groups of the longitudinal series. The second group
is, as shown in figure, assymmetrical, and seems partly to be fused with the lateral group; it consists of a
number of acicules and bristles. The tliird group consists of about ten fairly long setae, and is fairl)-
well separated from the following group, \\\^ foitrth one, with 15 comparatively short setae. This group
is almost completely fused with the Jiftlt one ; laterally to these two groups a longitudinal series of about
20 setae is found. Behind the central spot Nr. 3 a rather irregular transverse group of spinules is observed,
and behind the spot Nr. 4 a transverse row of more delicate spinules is found.

The lamina labia lis is granular, and has a concave posterior margin (fig. ic); the area in front as
well as that behind the lamina has as seen in figure a fairly interesting structure. The lateral series
of setae behind and upon the labial lobes show as seen in fig. i d an arrangement which is distinctly
different from that of Gaidius, as the two first series and partly the third are represented by four
areas of spinules.

J". Size of specimen from Ingolf St. 47 was 2-99 mm.; anterior division 2"i8 mm.; urosome o-8i
mm. CI eve's specimen measured 2-58 mm.

The body is comparatively longer and more slender than in the female; no frontal keel is found,
and the rostrum is fairly long and slender (text-fig. 29 b); no trace of limitation between head and first
thoracic somite was found. The anterior division is 2'6 as long as the abdomen. The first abdominal
somite, which has the genital opening as a vertical split on the left side, is about as long as the second
one; this is a little longer than the third, which is again a little longer than the fourth; the striated
seam along the hinder margin of somites II — IV is only indicated dorsally (text-fig. 29 c). The antennulae
extend about to the middle of the abdomen; the segment 10 is separated by a rather indistinct line
from 8 — 9; the limitation between segments 12 — 13 is indistinal posteriorly. The segments 20 — 21 are
well separated on both sides. The measurements are very similar to those of the female, but the segments
beyond 18 are comparatively shorter. The differences in the appendages are as in E. viessinensis. The

COPEPODA 115

antennae have the endopodite at least as long as the exopodite, and it extends beyond the Re VI; the
setae are better developed; the Re II has in the middle inwards a rudimentary tooth (for a Si). The
viandtbulae have as seen in fig. i e a fairly well developed but soft-skinned manducatory part with a few
rudimentary teeth. The maxillulac (fig. ih) have 7 plumous setae, of which the 2 proximal are some-
what shorter in Le i; the Li i, which is fairly well developed but soft-skinned, possesses a number of
soft setae, of which some, though more or less swollen at the base, have not yet lost ther original
shape, while others are represented by short eminences; the L,i 2 seems to be represented by a short,
somewhat ringed eminence without setae; the Li 3 (?) has a single setae; the basipod 3 + the Ri pos-
sess 4 plumous setae. The Re has 11 setae. The maxillae form a ringed, elongate, soft-skinned organ,
which bears slender setae along its inner concave margin. The maxillipes is longer and more slender
than in the female; the second basipodite has setae only on the Lobe IV, namely a strong plumous one
and a shorter one in addition to a sensory lobe. The pes I differs from that of the female by the almost
straight margin (fig. if); the St. of Re III of pes II h&s 37 teeth. The inner margin of the second
basipodite in the fourth pair of legs is only sligthly convex, without setae or teeth.

The pes V (text-fig. 29 d) provides great similarity to that of Gaetanus, but is nevertheless
distinctly different (PI. IV fig. i g). The Ri dext. is long and somewhat enlarged towards the end, where,
inside, it bears two short delicate setae. The Re I o^ II (?) of the right leg is fairly long and slender. The
Re III (?) is somewhat enlarged inwards, and then rather suddenly attenuated; exteriorly, at the base
of the terminal part, which distally has an inner membrane and has the pointed tip curved
outwards, a slender Se is placed; the distal part is at least 1-5 as long as the proximal. The Ri sin.
is fairly long and slender; the Re III of left leg, at the base of which a tuft of hair is found, is short,
almost fused with preceding segment and produced into a hairy spine-shaped protuberance.

The structure of the oral surroundings is in the main like that of the female (cf. fig. le); the
labruni proper, which partly overlaps the chitinous bed in which the manducatory part of the man-
dibulae is placed, is well developed, but appears, but for a terminal tooth, to be smooth outside as well
as inside. The labial lobes, which consist of soft ringed chitin, are just indicated, and do not possess
any hairs. The lamina labialis etc. are completely wanting. This structure corresponds well with the
rudimentary state of the masticatory part of the maxillulae, not being adopted for predatory purposes,
nor even for taking any nourishment at all.

Y^ (St. V). Size of female from Ingolf St. 47: 306 mm.; anterior division 2-44; urosome 0-62
mm. A young male measured 2"i4.

The limitation between the head and first thoracic somite is generally better marked than in
the adult female (text-figs 29!— j). The first one of the four abdominal somites is ventrally produced
in the female, barely so in the male (text-fig. 290. The appendages show the usual differences from
those of the adult females; the St. of Re III pes II has 14 teeth; an interesting difference is foimd
in the wanting glandular pore at the base of Se I Re III; the second basipodite of the fourth pair of
legs is smooth, while 7 short hairs are found in the females, corresponding to the spines of the adult
female-s. T\\& fifth pair of legs is as seen in text-fig. 29 f rather clumsy and quite unlike Cleve's
fig. 3 PI. II; the Re dext., which is longer than the Ri dext, and which has a strong terminal spine,

is distinctly longer than the Re sin.

15'

I l6 COPEPODA

Yg (St. IV). Size of female from Iiigolf St. 47 is 2-24 mm.; anterior division 1-85; urosome
039 mm. A male from the same station measured 2*i mm.

The appendages show similar differences as in G. Kriippi, f. inst. glandular pores are only found
at the base of Se Re II and Se 3 Re III; the St. of pes II has only 13 teeth; the inner margin of the
basipodite of the fourth pair of legs appears smooth. The only difference between the male and female
is found in the presence of a fifth pair of legs in the former (text-fig. 29 g).

Y (St. III). Size of specimen from Ingolf St 47 was 1-65 mm.; anterior division 1-3 mm.; uro-
some 0-35 mm.

The thoracic somites IV — V are well separated; the antennulae extend scarcely to the end of
the abdomen. The appendages show differences corresponding to those in G. Kruppi.

Abnormality. In a single adult female the right furcal branch had the third and the second terminal
setae dichotomously branched. There is a well marked difference between pellucid and less transparent
specimens with more prominent eggs. In most specimens the intestinal tract consists of a wide
stomach which, in front of the insertion of the narrow oesophagu.s, is continued into a wide coecal sac
and behind is turned upwards to meet the following portion, and the intestine proper. In a single
specimen the connection between the stomach and the intestine was twisted, and not lying on the
same level.

Occurrence. The Ingolf Exp. has on the west coast of Greenland collected a }oung male
(stage IV) ^6/6 95 St. 25 63°30 L. N. 54°25 L. W. \' 200—0 fm. Temp. 29° C. The Ingolf Expedition has
not collected this species in Denmark Strait, but the Thor has taken it at the following stations:

Thor '9/6 1904 St 152 65^00 L. X. 28°io L. W. Yt. 1000 M. Wire i f?, i y? (V), Yt 100 M. Wire i f?,

Yt ?3f?, 3y? (V), 3 yd' (V).
2% 1904 St 153 65°2o L. N. 27°i2-05 L. W. Yt. 800 M. Wire i y? (V).
=>% 1904 St 154 65^27 L. N. 27°io L. W. Yt 80 M.Wire i f?, 2 y? (V).
'76 1904 St 150 65°50 L. N. 26'53 L. W. Yt 400 M.Wire i y?.

In the Atlantic south-west and south of Iceland the Ingolf Expedition has gathered the species
at the following stations:

18/6 1895 St 19 6o°29 L. N. 34°i4 L. W. V 300—0 fm. Temp. 9° C. 48 f?, 8 y? (V), 4 yd' (V).

17/6 1895 St 18 6i°44 L. N. 30°29 L. W. V' 200—0 fm. — 10= C. 13 f ?.

16/6 1895 St 17 62°54 L. N. 26=34 L.W. V 200— o fm. — 9-1° C. 2 f?, i y? (IV).

3/6 1896 St 68 62°o6 L. N. 22=30 L. W. V loo-o fm. — 8-8° C. i f ?.

9/8 1895 St 40 62=03 L. N. 2i°36 L. W. V' 100— o fm. — 13-5= C. 9 f ?.

V6 1896 St 63 62=40 L.N. i9°05 L.W. V' 100— o fm. — 8-3=0. 6 f?, 2 y? (V).

19/5 1896 St 55 63=33 L.N. i5''o2 L.W. V' loo-ofm. — 8-4=0. i yd* (V).

■=/5 1896 St 47 6i''32 L.N. 13=40 L.W. V 100— ofm. — 10-6= C. 2 f?, 17 y? (V), 4fd', 10 yc? (V),

ly? (IVj, I yd" (IV), I y (III).

S/S Thor has south of Iceland gathered the species at 14 stations, but at 9 of these onl> a
few adult females were found.

COPEPODA

117

Thor Vg 1904 St. 285 62°49 L. N. i8°46 L. W. Yt. 100 M. Wire 148 f?, i y? (V), i Vc? (V).

V9 1904 St. 285 62°49 L.N. i8°46 L. W. Yt. 800 M. Wire 31!?.

"/y 1904 St. 183 6i°3o L. N. i7°o8 L. W. Yt. 1800 M. Wire 750!?, 3 vcT (V).

^5/5 1904 St. 104 62°47 L.N. i5°o3 L. W. Yt. 1500 M. Wire 2 yj" (V).

In the Iceland— Faeroe channel the Ingolf Expedition has taken the species at 3 stations, and
the S/S Thor at 5 stations.

2% 1896 St. 57 63^37 L.N. 13^02 L. W. V 100 -ofm. Temp. 8-2° C. i yd" (V).

2% 1896 St. 59 65°oo L. N. ii°i6 L. W.Apstein 12 II-45P. m. — 1-5^0. i y? (IV).
'Vs 1896 St. 45 6i°3i-5 L.N. 9°43 L.W. V 100— o fm. — 9-1° C. i yd" (V).

Thor 28/8 1905 St. 163 62°36 L. N. i2°05 L.W. Yt. 300 M. Wire 3 f?.

"/s 1904 St. 100 6i°2i L. N. io°39 L. W. Yt. 180 M. Wire i f?, 3 yd" (V).

=^9/8 1905 St. 164 6i°20 L. N. ii°oo L.W. Yt. 300 M. Wire 35 f?.

29/8 1905 St. 165 6o°oo L.N. io°35 L.W. Yt. 100 M.Wire if?.

23/7 1905 St. 124 61^04 L. N. 4°35 L.W. Yt. 1000 M.Wire i f$.

The Danish East-Greenland Expedition has, '% 1900 10 p. m. F. 346 at the surface near Kap Dan
(Tarsuak Fjord), taken a single adult female.

Lundbeck has 'S/, 1890 55°25 L. N. 29=5 L.W. gathered i £?, i y? (IV).

The S/S Thor has, outside the Ingolf area south west of the Faeroes, taken the species at four
stations, but at the two only a few adult females.

Thor 76 1905 St. 72 57°52 L. N. 9°55 L.W. Yt. 1500 M. Wire 125 f? (one with spermatophor).
21/6 1905 St. 90 47°47 L.N. 8°oo L. W^ Yt. 300 M.Wire 139 f? (one with spermatophor).

Distribution. This species has been recorded from the Mediterranean, and from the Atlantic
as far north as 55° L. N. 10° L. W. ; it has been taken by the Monaco and by the Gauss Expeditions
in the Mid and South Atlantic; by the Gauss it has been taken at 45 L. S. 35 L. E. south of the Cape.
It was not taken by the Siboga, but Esterly records it from the CaHfornian Bay, and based on some-
what too small material he draws the following conclusion (191 2 p. 311) "evidently, the species moves
upwards at night if the numbers taken then as compared with those during the day can be taken as
representative of the whole population".

I think we are right in regarding this species as in the main an Atlantic one, which frequents
the intermedial strata, but occasionally is found from the surface down to a depth of about 1000 meters.

Remarks. The described species is certainly identical with that described by Giesbrecht, in
spite of the larger size, the wanting seta of Le 2 of maxillulae and the structure of the spines in the
Basp. II pes IV. The male, which CI eve refers to this species, is possibly identical with mine; his des-
cription is too incomplete to settle the question at present. I think that Giesbrecht is right in refer-
ring the small Atlantic specimens of E. Hessii Brady to this species, the bigger ones may perhaps be
identical with E. rostroniagna Wolf.

Ii8

COPEPODA

32. Euchirella curticauda Giesbrecht.
(PI. IV figs 3a — m; PI. VIII, figs 2 a — c; text-figs 29a — e.)

iSSS. Kuchirella curticauda n. sp. Giesbrecht, p. 356. I 1905. Euchirella curticauda Giesbr. Farran, p. 35.

1S92. — — Giesbr. Giesbrecht, p. 233, taf. 15, 36. 1906. _ _ _ Esterly, p. 59, pes 9, 10,

1898. — — — Giesbrecht & Schnieil, p. 36. 12 — 13.

1902. — — — J. C. Thompson, p. iS. 1906. — — — Pearson, p. 15.

1904? — — — var. atlantica n. var. Wolf- 1 1908. — — — v. Bremen, p. 48, fig. 54.

enden, p. 116. 1908. — — — Farran, p. 38.

1905? — atlantica n. sp. Wolfendeu, p. 20. 1 1909. — — — ^ A. Scott, p. 55.

1905. — curticauda Giesbr. G. O. Sars, p. 4. 1 1911. — — — Wolfenden, p. 236.

Description, f?. Size: Specimen from Thor St. 88 4-26 mm.; anterior division measured 3-61 mm.;
urosome 0-65 mm. Gie'sbrech t's specimen measured 3-5, Farran's 43 — 4-8.

The head has a prominent rounded frontal keel (PI. IV fig. 3a); the frontal organ is fairly pro-
minent at the base of a low prolongation downwards from the keel; the rostrum, which is only visible
from beneath, is short and undivided, but sometimes asymmetrical with an accessory tooth on the right
side. The articular membrane between the head and the first thoracic tergite is indicated in some spec-
imens, but is completely wanting in others. The posterior margin of the first to fourth tergites is
strongly chitinized, and falls on each side naturally into a lateral and two median divisions; behind the
hinder margin of the fourth tergite and partly covered by it, the fifth thoracic tergite, hollowed like a
gutter, is found. The cephalosome is about 6-5 as long as the abdomen. The genital somite is distinctly
produced below, and has, on each side of the vulva, a lateral projection, generally visible from the side;
along the hinder margin of this somite is a marginal seam. The antennulac almost reach to the end of
the genital somite, the appendages are a.s in E. messinensis. but the measurements are distinctly different,
as the distal segments are comparatively shorter; the 80^9 segments, f. inst, are about as long as seg-
ment 15, not much shorter. The antenna is in its main features like Giesbrecht's fig. 3 Taf. 15, but
a distinct articulation is found between Re I and Re II. The maxillulae stand as pointed out by Gies-
brecht, between E. rostrata and messinensis; the Le i has 9 setae, but the Li i has, as in messinensis,
only 3 posterior setae, and the Li 2 4 strong setae; the Li 3 and basipodite 3 are also like this species,
but the Ri has 3 setae only. The maxillipes has, exteriorly, near the tip of the anterior surface of the
second basipodite, as mentioned by Giesbrecht, a characteristic knob-formed process.

The margin between Se i — 2 of Re I ^ II in the /frj/ fair of legs is only slightly concave, with
a minute pore. The /rj // (text-fig. 29 a), which has 26 teeth in the St., has a well developed first Se
in Ri, and the same number of secretory pores as in the preceding species. The (^cs III has a distinct
accessory tooth at the base of Se Ri I ; the glandular pore in Re I seems to be wanting (text-fig. 29 b).
The number of spines interiorly on the posterior surface of basipodite II in pes IV varies from 7 to 13,
and is most often different on the two sides; the accessory tooth of Se Ri I is smaller; the secretory
pore in the Re I is sometimes indicated.

The anterior surface of the la brum is like that of E.jostrata. The chitinous system which
supports the oral surface of the labrum attains a characteristic development, as seen in fig. 3 c, as
the anterior bars are directed towards the middle, almost touching each other, and almost encircling the
median circular spot Nr. 3. The groups of setae in the longitudinal series show a characteristic ar-
rangement: the first groxip consists of an area covered with about 30 short strong spines; the

COPEPODA

119

second group is represented by a longitudinal row of about 20 minute spines; the third group (cf.
PI. IV fig. 3 c) consists of 5 fairly long and slender setae placed more forwards, and lateral, and of 2—3
placed more inwards and backwards; the fourth group, which consists of 20—25 fairly strong setae,
has a characteristic shape, as it is convex, and has its right and left parts converging towards the
middle, and almost touching each other in front; the fifth grotip is a continuation backwards of the
fourth, and consists of about 30 more delicate setae. Behind this group an oblique, almost transverse
row of short "spines" is observed. Behind the central spot Nr. 3 no transverse row of setae is ob-
served, but behind Nr. 4, which is single, two transverse rows of rather delicate setae are observed.
The lamina labialis (fig. 3 d), which is distinctly granular, is indistinctly divided into three parts. In
front of it, in the middle, is a longitudinal row of short spines on each side, followed by the two areas
of acicules, forming a curvature corresponding to the outer row of setae (cf. fig. i c); the latter is single
behind, double in front, as a lateral row of shorter setae is found. The arrangement of the spinous
areas behind the lamina as well
as of the series of hairs on the
labial lobes is seen in figs 3 d — e.

The intestinal tract is
almost straight, with a short
restriction between the anterior
and posterior divisions, and with
a slender coecal sac in front.

fc?. Size of male from
Thor St. 88 373 mm.; anterior di-
vision 2-92 mm.; urosomeo-8i mm.

The head has a distinct
frontal keel (fig. 3f), somewhat
longer and lower than in the

female; the body is rather elongate, and attenuated in front as well as behind. The head and the first
thoracic tergite are completely fused; the articular membranes between the thoracic tergites are like
those of the females. The anterior division is 3-5 as long as the urosome; the genital pore is found
on the left side of the first abdominal somite; the furcal rami are short, rounded, and about as long as
wide; their St. 2 is a little longer than the abdomen, and almost twice as long as the Si.

The antennulae extend a little beyond the end of the cephalothorax; the segments 2 and 3, 4
to 7, 8^9 and 10 as well as 11 to 14 are more or les fused; the segments 20—21 are completely fused
on the right side, well separated on the left side. The appendages are Scarcely different from those of
E. messinensis; they are as a whole more soft-skinned than in the female, and the Sp. of segment 23
is much shorter than that of segment 24. The segment 2 is almost i-i as long as segment 17, which in
length is equal to 15, 16 and 19, and about it as long as segments 8<>J9. Segment 20 is on the left
side about as long as 80^9, but 20<v2i on the right side combined is the longest segment, and almost
1-4 as long as segment 2. The antennae have the Re 1-5 as long as Ri, and have well developed distal setae;
the Re I and II are well separated, but the medial tooth of Re I is wanting. The Le of the maxillulae

Text-fig. 30. Euchirella airticauda Giesbr.
a. ft?. Pes II sin. in ant. view x 40. b. f 9. Pes III x c. 40. c. y 9 (stage V). Pes III
X c. 40. d. yd" (stage IV, a single specimen from Thor 20/5 1905 vSt. 88 not men-
tioned in the text). Pes III sin. X c. 50. e. y9 (St. V). Pes V X 60.

J20 COPEPODA

possesses 9 setae, of which the 2 proximal ones are extremely short, the third one is distinctly shorter
than the strong powerfull S 4—9, of which again S 6 — 7 are the longest. The Li I is well developed
but has only a few short soft appendages; the Li I— II were not observed; the Basp. Ill (?) is quite
rudimentary, with at least a single almost rudimentary seta, and the Ri I — III iBasp. III?i bears 4 stiff
fairly long plumous setae. The Re has 10 well developed plumous setae in addition to an inner quite
rudimentary one. The maxillae, have as seen in fig. 3 h, in the main preserved the shape in the female
and so has the maxillipes, which is however much more slender, and it has preserved the knob-shaped
process of the second basipodite, though it is less prominent than in the female.

The first pair of legs (PI. VIII, fig. 2a) is distinctly different from that of the female; the anterior
surface of the Ri has the process, which is situated laterally at the end of the chitinous list, forming the
margin of the rounded lobe, more prominent and perforated by about 3 canals for delicate ducts ; between
the Re I and II a distinct articulation is found; the Se Re I is short, delicate and swollen at the base; the
outer margin of Re II is almost straight, with a distinct pore placed somewhat beyond the middle;
the pore in the outer margin of Re III, which is scarcely indicated in the female, is well developed,
and placed somewhat beyond the middle. The pes II differs by well developed articulation between
Ri I and IltvUI, and by the comparatively short Se Re I and the /itj /F with the smooth inner margin
of the second basipodite. The fi/lh pair of legs shows similarity not only to that of E. mcssinensis
but also to that of E. rostrata; the two legs are almost of equal length (figs 3 g— i). The pes dcxt. has
a rather short second basipodite, partly fused with the corresponding one of the left side, and a long strongly
enlarged third basipodite, which has an inwards process, which bears the rather slender Ri (PI. VIII
fig. 2 c) extending somewhat beyond the end of Re I^^-II; it is most narrow in the middle, extending,
as well, towards the base, but especially towards the tip, and the anterior surface is slightly concave,
with the lateral margin somewhat turned over inwards; the lateral margin has two distal processes, of
which the one is placed near the tip. The Re I — -11 is long and slender, without distinct processes. The
Re III is as seen in fig. 3 j irregularly curved, and has near the base a plate-shaped process; in the distal
half the inner margin possesses a few big teeth, and a more distally dense serration. The lefi leg has
the basal segments long and slender, as seen in fig. 3 i ; the obtuse and slender Ri extends somewhat
beyond the proximal third of the Re I. The Re I is moderately long and slender; it bears a delicate
Se at the base of Re II; the Re II is rather short, and apparently excavated outwards and back-
wards (fig. 3 m); interiorly it is produced into a somewhat hairy process; at the base of this process is
the slightly curved, attenuated but blunt Re III (fig. 3 1 seen from in front and from the inside), which
inwards has two hairy processes basally, and terminally a marginal seam of short hairs.

Y^ (St. V). Size of female from Thor St. 88 was 3-63 mm.; anterior division 3-06 mm.; uro-
some 0-57 mm. *

The body is more slender, and the abdomen consists of 4 somites without any difference between
the first somite in the male and the female. The antennae of the female are scarcely different from
those of the adult, except by the Ri, which is one fourth as long as Re, but they are distinctly diffe-
rent from those of the male, in which the Ri is almost half as long as Re, well developed and pos-
sessing 5 well developed setae in Le and 3 long -^ 2 rudimentary ones in Li, a number which is smaller
than that of the adult male (6 -x- 7), and bigger than that of the female (3 -- 2). The legs are in minor

COPEPODA 121

features different from those of the adults; the Re III has no secretory pore at the base of Se I; the
outer tooth of Ri I pes II is bhuit, and the corresponding accessory tooth of pes III is just indicated
(text-fig. 30 c). The inner margin of the second basipodite is smooth in the male, but has in the female
about 10 short delicate but rather stiff bristles. The pes V is similar to that of E. rostrata, but there
is no indication of subdivision of Re; the terminal spine of Re dext. is longer and less sharply set
off, and that of left Re is much shorter (text-fig. 30 e).

Variation. In a single male the exopodite of the second foot was curiously transformed, as seen
in fig. 2 b (PI. VIII).

Occurrence. The Ingolf Expedition has not taken any specimen of this species, but the Thor
has gathered it at the following stations.

In Denmark Strait:

'9/6 1904 St. 152 65°oo L.N. 28°io L. W. Yt. 1000 M. Wire i i,}.
-/6 1904 St. 153 65°20 L. N. 27^12-5 L. W. 3 f ?.

"It 1904 St. 154 65°27 L.N. 27"'io L. W. if?.

In the Atlantic' south of Iceland: ■

9/7 1904 St. 178 63°o8 L. N. 2i°30 L. W. Yt. 750 M. Wire i i<}.

^°/y 1904 St. 180 6i°34 L. N. i9°05 L. W. Yt. 1800 M. Wire i f?.

"/7 1904 St. 183 6i°30 L. N. i7°05 L. W. Yt. 1800 M. Wire 14 f? (3 with spermatophors).

25/5 1904 St. 104 62°47 L.N. i5°03 L. W. Yt 1500 M. Wire 10 f?.

V9 1904 St. 285 62°49 L. N. i8°44 L. W. 13 f ?.

29/8 1905 St; 164 6i°20 L. N. ii°oo L. W. Yt. 300 M. Wire 16 f$ (5 with spermatophors).

"/s 1904 St. 99 6i°i5 L.N. 9°35 L. W. Yt. 1400 M. Wire i yc? (V).

1^5 1904 St. 78 6i°o7 L. N. 9°30 L. W. 2 f ?.

Outside the Ingolf area south-west of the Faeroes a fairly large number of specimens has been
captured.

is/e 1905 St. 82 5i°oo L. N. ii°43 L. W. Yt. 1200 M. Wire i f?, 3 fc?, i y? (V).

Yt. 800 M. Wire 1 1 f $ (3 with spermatophors).

"/g 1905 St. 167 57°46 L. N. 9°55 L. W. Yt. 1500 M. Wire 16 f? (5 with spermatophors).

8/6 1905 St. 72 57°52 L. N. 9°53 L. W. Yt. 300 M.Wire 51 f?, 1 fd*, i yc? (V).

2% 1905 St. 88 48°09 L.N. 8=30 L. W. Yt. 300 M.Wire 200 f? (30 with spermatophors), 7 f c?,

2 y? iV), 2 yc? (V).
^76 1905 St. 90 47°47 L. N. 8°oo L.W. Yt. 300 M.Wire 5 f?, i fc?.

Distribution. "This species" is according to Far ran "of frequent occurrence, and often moder-
ately common" on the west coast of Ireland "at depths of from 200 to 1000 fathoms". It has been taken
by the Monaco Exp. and by the Gauss' Exp. as far south as c. 10° Lat. S. It has been recorded from
the Bay of California and from the Malay Archipelago.

Remarks. This species is certainly identical with that described by Giesbrecht and Esterly,
though it is somewhat bigger, and in spite of some features, e. g. shape of fifth thoracic tergite, which

The Ingolf-Expedition. III. 4.

122 COPEPODA

are not mentioned in Giesbrecht's rather short description. The species is ijrobably identical with
Wolfendens 't'ar. aflantica, as the differences set forth viz: "head separated from first thoracic segment",
basipodite II of pes IV, which has "only six rather broad-based and long spines", and the smaller size
(3-8 mm.) are not of much importance. It is more doubtful, if it is identical with E. atlaniica Wolf., in
which the abdomen is only '/s of the anterior division in length. Most probably the described male
belongs to this species, especially on account of the characteristic articular membranes of the thoracic
tergites, the frontal keel, the almost absolete rostrum and the knob-like process of the second basipodite
of the maxillipeds. The arrangement of secretory pores and the structure of Se of Ri I in the legs are
like those of the females. Some of the differences are certainly due to sex, f. inst. longer abdomen,
longer endopodite of antennae with greater number of setae; a few of the other differences are not
quite the same as those found in related species, but it must be remembered that sexual differences
are apt to vary from the one species to the other.

33. Euchirella messinensis Clans.
(PI. IV figs 2 a— c; PI. VIII fig. i; text-figs 31 a— f.)

1S63. Undina messinensis n. sp. Claus, p. 187, pi. XXXI. 1904

1S92. Euchirella messinensis Claus. Giesbrecht, p. 232, taf. 15 1905

&36. I 1905

1S94. Nee. — — — Th. Scott, pp.45 — 46. I 190S.

1896. — — — Canu, p. 424. I 1909

1898. — — — Giesbrecht & Schmeil, ' 1909

1912

P- 31-

1903. — — — Giesbrecht, p. 201.

1903. — — — Thompson & Scott, p. 244.

1911

Euchirella messinensis Claus. Cleve, p. 190.

Esterl}', p. 151, fig. 18.
G. O. Sars, p. 4.
Farran, p. 37.
Pesta, p. 23.
A. Scott, p. 56.
Pesta, p. 13.
Wolfenden, p. 237.

Description. f$. Size of specimens from Thor St. 183 57 mm.; anterior division 4-5 mm.; uro-
some 1-2 mm. Giesbrecht's specimens measured 475 mm.

The sac-shaped protuberance of the genital somite, which is rather variable in the specimens
examined, differs somewhat in shape from Giesbrecht's fig. 18 (Taf. 36); it is distinctly widened out
towards the end, does not reach much behind the end of the third somite and beyond a distinct con-
cavity at the right side the tip is directed towards the right; the protuberance is dorsally excavated.
The Ri of the antennae possesses 5 setae in Le and 3 (not 4) in Li. 'Th^ first pair of legs has the outer
margin between the Se of Re I — II almost straight with a distinct pore, continued into a conical
process at least in one specimen. The glandular pore in the outer margin of Re III pes 1 is placed Yj
of the length of Re III measured from the base. The number of glandular pores is as in E. rosfrafa\
in the Re I exteriorly distinctlj- removed from the tip a transverse split (secretor}" pore) was observed
not only is pes II but also in pes III — IV, in which the real pore is found ; a similar one was observed
in Basp. Ill medially to the insertion of Se I, and in Re III near to the insertion of Si 4.

Somewhat behind the insertion of the antennulae a well marked elevation 'is found, which is
well separated^from the labrum proper by an anteriorly convex chitinous line; in connection with
the mentioned elevation as well as with a transverse chitinous bar behind the mouth a strong
chitinous system forming a covering for the manducatory part of the niandibulae is found. The an-
terior surface of the labrum does not possess any setae in front of the marginal row; this consists, on

COPEPODA

123

each side of the median concavity, of a medial transverse row of about 25 more spine-shaped setae.

The chitinous system of the oral surface of the labrum (fig. 2 a) shows as seen in figures (cf. 3 c) some

similarity to that of E. curticmoda^ but the arrangement of the groups of hairs in the longitudinal

series is distinctly different, and is indeed very characteristic. T\\q first group consists of about 30— 40

setae, placed in a single inwards convex row; th.& second group, which is perhaps fused with the lateral

group, is represented by a big group of minute acicules; the third group consists of about 20 fairly

long setae, and is converging towards the front; ^t. fourth group, consisting of about 25 fairly strong

setae, has the anterior portion placed almost transversely, and is almost fused with corresponding part of

the other side; t\\e. fifth group, which consists of about 40 rather slender setae, is partly fused with the

fourth; the sixth group is transverse, and consists of short delicate hairs. No transverse series of

spinules is observed behind the median circular spot Nr. 3,

and the two series behind the fourth median spot are fused

to a square area, beset with spinules.

The lamina labialis, as seen in fig. 2 b, is smooth and

very insignificant; the arrangement of setae in front of lamina

is, as seen in fig. 2 c, somewhat different from that of E. cur-

ticauda. Behind the lamina 3 — 4 sijinous areas are observed

on each side. The series of hairs behind and upon the labial

lobes show a rather regular arrangement, as seen in fig. 2 c,

the medial posterior groups of a few hairs could not naturally

be referred to any of the series. The first series consists of a

number of short hairs, placed in a rounded area ; the second Text-fig. 31. Euchireiia ,nessintnsis Claus.

a— b (to the left), f 9. Ri pes II— III X 57- c. Pes
series consists of two rather independent almost transverse y dext; ridges of Re iii x 175. d— e (in the

rows; the third series seems onlv to be represented on the ""'^'^'^ ^^'°^^) ycT (St. V) Ri pes ii-iii x 57-

f. yd". Pes V ant. view X 57-
labial lobes, and the fourth one has in addition to the regular

row on the lobe a more medial and posterior portion; t\i& fifth group, which consists of somewhat

stronger setae, falls naturally into a median portion which is fused with the corresponding part of the

other side, and a lateral one which is continued to the end of the labial lobe.

c?. Size of specimen from Thor St. 183 5-46 mm.; anterior division 437 mm.; urosome 109 mm.
Giesbrecht's specimen measured 3-95 mm.

The frontal keel is distinctly higher than figured by Giesbrecht (Taf. 36 fig. 25). The oral ap-
pendages are practically like Giesbrecht's description, but the mandibulae possess as in Euch.
rostrata a well developed manducatory portion; the labrum and labium show a similar development
as in this species.

According to Giesbrecht (p. 240) the only difference between the natatory legs in males and

females is found in the completely smooth inner margin of the fourth pair of legs in the males; in

my specnuens, however, the difference is even better marked than in E. rostrata and curticauda (PI.

VIII fig. I). The articulation between Re I and II pes I is indicated, but the Se Re I is wanting;

the Se Re II is quite rudimentary; the pore in the outer margin of Re II is well developed, but

that of Re III seems to be wanting: The St. of the Re III pes II has about 50 instead of c. 25 teeth.

16*

124

COPEPODA

The Ji/fh pair of legs is scarcely different from Giesbrech t's fig. 21 (Taf. 15); the teeth along
the inner margin of Re III pes V dext. correspond really to transverse keels, as seen in text-fig. 31 c.
Yp (Stage V). Size of male from Thor St. 88 4-19 mm.; anterior division 3-29 mm.; iiro-
some 0'90.

The shape of the body is in the main as in adult female, without frontal keel. The appendages
are in the main like those of the adult female, except the antennae; these organs show similar dif-
ferences as in E. curficanda; the antennae of the female is in the main like those of the adult, with
rudimentary Ri, which, however, has the setae of Ri 2 better developed (in Li 4 setae); the antennae
of the male are like those of the adult by the more powerful Ri, which, however, only reaches the middle
of Re 2, and has a similar number of setae as in the female. The natatory legs differ somewhat from
those of the adult by the less developed Se of Ri I, as seen in text-figs 31 d — e, as well as by the wanting
glandular pore at the base of Se i Re III. The inner margin of the second basipodite in the fourth
pair of legs is smooth in the male, but has in the female about 6 short delicate bristles. The. Ji/t/i pair
of legs has, as seen in text-fig. 31!, a characteristic structure resembling that of the adult male.

Occurrence. The S/vS Thor has gathered a few specimens of this species at the following
stations:

'V; 1904 St. 183 6i''3o L. N. i7°o8 L. W. Yt. 1800 M. Wire 5 f?.
24/6 1905 St. 93 49°25 L. N. i2°20 L. W. Yt. 200 M. Wire i f ?.
15/6 1905 St. 82 5i°oo L. N. ii°43 L. W. Yt. 1200 M. Wire 2 f?, i yj" (V).

800 M. Wire 2 f?, 2 f J".
% 1905 St. 88 48-^09 L. N. 8^30 L. W. Yt. 300 M. Wire 2 f ?, 1 fd*, i y? (V), i y^ (V).

Distribution. The species, according to Farran, is fairly common on the west coast of Ireland
"at depths of from 350 to 700 fathoms". It has been recorded from the North-east Atlantic, the South
Atlantic, the Mediterranean, the Wala)- Archipelago and the Pacific (Bay of California).

Remarks. In spite of the mentioned small difference the female must be regarded as identical
with E. vicssinensis; if the difference in the first pair of legs between my male and Giesbrecht's is
really a constant one, the identification of the males seems to be rather doubtful.

34. Euchirella intermedia n. sp.

(PL IV figs 4 a— c; PI. YIII fig. 3; text-figs 32 a— f.)

1902? Euchirella carinata n. sp. Wolfenden, pp.366 — 367.

191 1? Euchirella gracilis n. sp. Wolfenden, pp. 237, test-fig. 22, tafel XXVII figs 8 — 10.

Description. f$. Size of .specimen from Thor St. 82 5-66 ram.; anterior division 4-66 mm.; uro-
some I mm.

No frontal keel is found; the short strong rostrum is directed forwards and downwards
(cf. text-fig. 32 e). The articular membrane between head and first thoracic tergite is present laterally;
the articular membranes between the thoracic tergites show similarity to those of Euch. cnrticatida;
the fifth somite is laterally indicated as a mere marginal seam, and the lateral corner is rounded as
seen in fig. 4 a.

COPEPODA 125

The abdomen, which is -^ as long as the anterior division, has the furcal rami about as long
as the fourth somite, and about as long as wide. The genital somite, which is as deep as wide, is
somewhat wider than long; in dorsal view it is distinctly asymmetrical and more convex on the left
than on the right side; on the left side, near the hinder margin, we observe a lamellous process with
broad base, and directed backwards and somewhat outwards; behind this, as seen in fig. 4a, another
less prominent elevation was observed. The genital area is well produced in front, and the median
prominent crista, which is prominent in Giesbrecht's fig. 21 (Taf. 36) oi E. venusta, was not seen.
The triangular teeth along the hinder margin of abdominal somites 10^2, 3 and 4 are only poorly
developed.

The antennulae reach the end of the body, their appendages are scarcely different from those
of E. messhiciisis, and the measurements are very much alike. The endopodite of the antennae is about
half as long as the exopodite, and its second segment has 9 setae in Li and 9 in Le. The Re I, which
has a well developed conical process without any seta, is fairly well separated from Re 2 (PI. VIII
fig. 3). The Diaxillulae differ from those of Euc. viessinensis by the presence of a less powerfuU Sa in
Ri I. The viaxillac have the outer margin rather suddenly produced as in E. rostrafa, but are in other
respects scarcely different from E. viessinensis^ the maxillipeds differ from those of the latter species
by the almost straight exterior margin of the third basipodite. The glandular pore in the outer margin
of Re III of pes I is more removed from base, in other respects the first pair of legs is like E. vies-
sinensis. The Se of Ri I of pes II is more prominent than in E. viessine?isis (cf. text-fig. 31a); the ac-
cessory tooth of the Se Ri I is indistinct in pes III, and completely wanting in pes IV. As in E. cur-
ticauda no glandular pore was found in Re I of pes III — IV. The second basipodite of the fourth pair
of legs has only a single strong spine, extending to end of segment (text-fig. 32 a).

The labnivi is in lateral view like that of Euc. iiiessineiisis; its oral surface (fig. 4 b) is in
structure lying between that of E. ii/cssinoisis and curticauda (fig. 2 a and 3 c). The first group consist of
an area with densely placed, fairly strong spines; the second group is represented by 2—3 longitudinal
rows of short teeth, laterally to which a similar longitudinal row is seen ; the third group consists of
about 5 fairly long spines, placed medially to and partly in front of the posterior part of second group.
Behind the median spot Nr. 4 a square area of small spinules and a posterior transverse row are found.
The laviina labialis (cf; fig. 5 f) is like that of E. viaxivia Wolf., but is more distinctly granular posteriorly.
The area in front of lamina labialis is like that of E. viessinensis, and so is the area behind, which,
however, in the posterior groups shows some not quite unimportant differences.

f c?. Size of male from Thor St. 88 5-3 mm.; anterior division 4-2 mm; urosome i-i mm.

The body is distinctly more slender than in the female. No frontal keel is found, but the
rostrum is longer and directed more downwards (text-fig. 32 b) ; the lateral corners are rounded, and the
fourth and fifth thoracic tergites are completely fused. The abdomen is distinctly one fourth as long
as the anterior division. The furcal rami are a little wider than long; the serrated seam along the
hinder margin of somites II — IV is fairly well developed.

The antennulae extend to the end of the abdomen ; the appendages are scarcely different from
those of E. viessinensis; segments 8009 are completely fused with segment 10; segmerrts 12 and 13, 14
and 15 are more or less fused. The exopodite of the antennae is 1-4 as long as the endopodite, the

126

COPEPODA

Le of which has 5 setae, while its Li has 7 setae. The muxilhdac are scarcely different from those
described in E. curHcauda\ the maxillae agree in general shape (cf. fig. 311 PI. IV), but the setae of the
four proximal lobes are poorly developed, while the fifth lobe has a long, soft, somewhat contorted sensory
seta in addition to one fairly slender and one very short of usual structure; the inaxillipeds are as
usual more slender than in the female.

The first pair of legs is as usual well distinguished from that of the female ; the first and

the second outer segments are marked off from each other by a small incision, proximally to which the

short, at base swollen, Se is found; the Se of Re II is short and moderately slender; the position of

b the glandular pores in the outer margin

/ \ of Re II and III is as in the female. The

third pair of legs differs by the better
developed accessory tooth of the Se Ri
I, and the fourth pair by the smooth
inner margin of the second basipodite.
Th&Ji/th pair of legs is much longer
than the abdomen, and extends almost
to the end of the furcal setae; both
legs are very similar to those of E. 1/1 fs-
sinensis (text-figs 32 c— d); the processes
on the margins of the rami of the right
leg are slightly different from those of
the mentioned species. The right endo-
podite seems to be wanting; the right
exopodite is terminated by three some-
what hirsute processes (cf. text-fig. 32 d),
of which the first is hook-shaped with
three teeth, the second is flat and rounded, while the third one is slightly hook-shaped without serrations.
Y S (St. V). Size of female from Thor St. 88 478 mm. ; anterior division 3-91 mm.; nrosome 0-87 mm.
The shape of the body is practically like that of the adult female with the usual differences
in the shape of the abdomen; triangular teeth are found along the hinder margin of somites II — III.
The only difference of importance which was observed in the mouth appendages was found in the
antennae, which in the female as well as in the male is like that of the adult female, but in Le Ri
only 6 setae are found and in Li 7. The Se of Ri I is blunt, and only slightly prominent in the
second pair of legs, and its accessory tooth is almost obsolete. The inner margin of the second basi-
podite in the fourth pair of legs is smooth in the male as well as in the female. The fifth pair of
legs of the male shows (text-fig. 32 f) on the one side a distinct similarity to that of E. messiiiensis, but
is on the other side distinctly different, f. inst. by the short rounded left endopodite.
Occurrence. The SiS Thor has gathered this species at two stations viz:
'5/6 1905 St. 82 51^=00 L. N. ii°43 L. W. Yt. 800 M. Wire 2 f?, 19 y? (V), 2 yd' (V).
^°/6 1905 St. 88 48^09 L. N. 8°30 L. W. Yf. 300 M. Wire i fc?, 2 y? (V), i yc? (V).

Text-fig. 32. Eiichirella intermedia n. sp.

a. f9. Pes IV sin. in post, view X 33- b. fc?. Head X i35- c- f d". Pes V

in post, view X 145. d. fd". Pes V sin. X 275. e. vQ (St. V) head X 33-

f' yc? (St. V) pes V in anterior view X 57-

COPEPODA

127

Remarks. The male of this species is very similar to E. pulchra Giesbr., while the female seems
to be nearly related to E. venusta Giesbr., but is distinctly different by the shape of the genital somite, the
larger size, the much longer endopodite of the antennae with greater number of setae and the single
spine in the second basipodite of the fourth pair of legs. It is possibly identical with Wolf end en's
E. gracilis (p. 237 1911) from the South Atlantic, which agrees with it in several of these characters, as
far as can be seen from the short description, but as the genital somite in dorsal view has a different
outline and laterally is "ohne Auswiichse", and as the endopodite of the antennae has 8 + 7 terminal
setae, I feel justified in regarding my species as a new one. Between Wo If end en's description of a
young male of E. carinata and this species there is some similarity.

In spite of the somewhat curious difference found in the number of setae in the endopodite of
the antennae I do not doubt that the young specimens belong to the same species. In all features of
importance, even the wanting glandular pore in Re I of pes III — IV, they aggree with the females.

In several respects this species bears similarity to E. curticauda Giesbr.

35. Euchirella maxima Wolf.
(PL IV figs 5 a — h; Text-figs 33 a — i.)

1905. Euchirella maxima n. sp. Wolfenden, p. i8, pi. VI figs

9— II.
1908. — — Wolf. Farrau, p. 38.

1909. Euchirella maxima Wolf. A. Scott, pp. 57— 58, pi. XII

figs 12 — 20.
191 1. — — — Wolfenden, pp. 23S — 239, taf. 28

figs 3 — 5 ; text-figs 24 a — b.

f$. Size of specimen from Thor St. 88 was 7-8 mm:!^anterior division 6-5 mm. ; urosome 1-3 mm.
A specimen from Thor St. 167 measured 8-5 mm. Wolfenden's specimen measured 7-5 — 87 mm.

The head is mounted with a well marked frontal keel. The rostrum is short, undivided and
in lateral view almost triangular. The first thoracic tergite is fused with the head. The fifth thoracic
tergite is, as stated by Scott, well separated from the fourth; it is narrow above, but below it is widened
out, and on the left side produced into an irregular, rounded lamina (fig. 5 b), but on the right produced
into a somewhat shorter pointed process (fig. 5 c); this interesting structure, which is rather variable
within the different specimens, has not been described by previous authors. The articular membranes
of the thoracic tergites are developed in a similar wa}- as in E. curticauda. The abdomen is only one
fifth of the anterior division; the somites are short and dorsally along the hinder margin have short bristles.
The lower surface of the genital somite (fig. 5 d) is produced, and has, somewhat in front of middle, on
the left side, a prominent pointed process, which is curved forwards and inwards. On the left side and
behind, a small protuberance, scarcely visible from above, is seen, and on the right a small anterior
process and a fairly prominent bigger one, which is placed more posteriorly and is partly visible in
dorsal view. The furcal rami are about as long as wide.

The antennulae reach about to the end of the genital somite; the segment 17 is about as long
as segment 2 and i-6 as long as segments 8"^ 9 and segments 24 — 25. The endopodite of the antennae
is only Vj of the exopodite; its Le of the second segment has only 3 moderately long almost naked
setae, and the Li has 5 somewhat shorter ones (the number of setae is according to Wolfenden as well
as to Scott 5 + 5); the Re I— II is distinctly longer than Re III— VII; the Re I, which has a pro-

128 COPEPODA

minent conical process without hair, is well separated from the Re II, which possesses a basal, a median
and distal short conical protuberance without any hairs ithe 2 first are shown in Scott's fig. 17). The
Le of the maxillulae possesses 8 setae, of which the 3 basal are rather short and delicate, and the fifth
moderately long, but much shorter than the fourth as well as the following one, which are long
and powerful; the number of setae is else as in the E. curticauda. The maxillae differ from those of
E. messtnensis by somewhat stronger spines and more pronounced spinulatiou on the posterior surface
of the lobes. The maxillipeds are most like those of E. curticauda ; the third basipodite is 2-5 as long
as the Ri, which has 4 setae in the Ri 2.

The Jirsl pair of legs is scarcely different from that of E. curticauda; the second pair of
legs has a well marked tooth in Ri I, and the Se Re II extends as .shown by Wo If en den at least
to the tip of Se I Re III; the third pair of legs has the accessory tooth, corresponding to Se Ri I pointed
and well developed; the second basipodite of the fourth pair of legs, which is strong, broad and of
triangular shape, extends barely to the end of the somite, aud seems, as figured by Scott fig. 20
PI. XII, to be formed by the fusing of about 4 spines. The pores are like those of E. messinensis.

The labrum (fig. 5 e), as seen in figure, has the inner marginal row well developed, but the
outer one seems to be represented by a few minute granules. The oral surface is in all main features like
that of E.. curticauda, but differs as seen in figures, as f. inst. by the third group, which is not conver-
ging but diverging posteriorly. The lamina labialis (fig. 5f) is striated but not distinctly granular; the
area in front of the lamina is rather similar to that of E. curticatida (cf. fig. 3 d), but the lateral series,
which forms the continuation of the serrula 6-dentata, has only a single row of fairly strong spines,
aud the inner series has about 25 short spines in a single row in addition to the usual area covered with
acicules, which starts behind the end of the inner series. The arrangement of setae behind the lamina
labialis and at the labial lobes (fig. 5 g) is, as far as series III — V are concerned, practically like that
of the preceding species, but as far as the first series is concerned is rather different

i% Size of specimen from Thor St. 167 was 67 mm.; anterior division 5-1 mm.; urosome i-6 mm.

The body (text-figs 33a— b) is moderately slender; the head and first thoracic somite are com-
pletely fused; the lateral corners are rounded, and the fourth and fifth somites are completely fused.
The head is surmounted by a fairly big, prominent, rounded, keel and has a short, strong, compressed
and undivided rostrum. The abdomen is about one third as long as the anterior division; the first and
second somites, which are of equal length are somewhat longer than the third, and about as long as the
fourth; the serration along the hinder margin of somites II — IV is short and delicate. The furcal rami
are about as long as wide; the St. II, which is distinctly longer than the abdomen and twice as long
as Si, is longer than St. I — III, and again longer than St. IV.

The antennulae extend to the end of the second abdominal somite; they are in most respects
like those of E, curticatida. The exopodite of the antennae, which has an indication of a protuberance
in Re I, is 1-4 as long as the endopodite, which possesses 5 setae in lyC and 7 setae in Li.

The maxillulae possess 8 setae in Le, completely like those of the female; the Li I aud II are
fairly well developed, and possess a few soft contorted appendages, and the Si of the Re is fairly long,
but in other respects the appendages are scarcely different from those of E. curticauda; the maxillae
and maxillipeds are practically like those of the preceding species.

COPEPOUA

129

T\iQ first pair (text-fig. 33 c) of legs is in most respects like that of E. cnrticauda; the process
on the anterior surface of Ri with 3 teeth, perforated by delicate canals, is almost obsolete; the Se of
Re I is fairly long and slightly swollen at the base; the pore in the outer margin of Re III is placed
distinctly nearer the base than the middle. The pes II shows a similar difference as that of E. curti-
cauda, with fairly well developed articulation between Ri I and II and comparatively short Se Re II.
The pes III — IV are like those of the females, but the inner margin of the second basipodite in the
fourth pair of legs is completely smooth.

The fifth pair of legs (text-figs 33 b and e — g) shows most similarity to that of E. cnrticauda; the
right and the left legs are of almost equal length; the Ri dext., which extends almost to the end of
Re IinjII, is terminally inflated, and outwards has two rounded processes in the middle; the Re III is

Text-fig. 33. Etuhirella maxima Wolf.
a. fd". Head X 34- b. f d. Abdomen X 20. c. frf. Pes I X 66. d. f d. Pes IV sin. Ri X 66. e. i<S. Pes V dext. Re II— III
X 66. f. f c?. Pes V sin. Re III (from below) X 107. g. f cf- Pes V sin. Re III (in exterior view) X 66. h. yd", (stage V) Pes V

in ant. view X 33- i- yc?- (stage IV) Pes V in ant. view X 60.

slender, gradually attenuated towards the tip and is in distal half, in a similar way as in E. messinensis,
regularly serrated along the margin (text-fig. 33 e). The left leg has a long and slender Ri, which
extends to the end of Re I and terminally is rounded and slightly convex in its whole length; the Re I is
fairly long and slender, somewhat concave inside and here possessing a few protuberances; the Re II is
somewhat shorter, with a basal rounded process and 2 distal ones, of which the one is short and conical,
while the other is about one third as long as the segment, and gradually attenuated, the Re III, which
is distinctly half as long as the Re II and placed at the base of the last mentioned process, is trian-
gularly pointed beyond a distal conical process and hairy along inner margin proximal to it (text-
fig- 33 0-

Yq (St. V). Size of female from Thor St. 88 is 6-04 mm.; anterior division 4-96 mm.; urosome ro8.

The shape of the body is like that of the adult, but the frontal keel is somewhat lower; the
lateral corners are rounded (fig. 5 h), not produced, and the fifth somite is dorsally as well as laterally
represented by a mere seam. The abdomen is about one fourth as long as the anterior division. The

The Ingolf-Expedition. III. 4.

17

130

COPEPODA

aniennae of the female are scarcely different from those of the adult female, but for the presence of 5
setae instead of 3 in Le; the antennae of the male are more similar to those of the adult male, as the Ri
is half as long as Re and has 7 setae in Li and 5 in Le. In the viaxilliilae of the female the S 14 of
Li I is distinctly shorter than S 13; this structure is probably due to individual variation, as S 13 and 14
in the male are of equal length. The legs differ from those of the adult female b\- the less prominent
Se of Ri I and by the completely smooth inner margin of the second basipodite in the fourth pair of
legs in male as well as in female. The fifth pair of legs (text-fig. 33 g) is distinctly different from
that of preceding species, as both Re as well as Ri are of almost equal length, and as the left leg is
distinctly pointed.

Yq (St. IV). Size of female from Thor St. 88 4-69 mm.; anterior division 4-0 mm.; urosorae 0-69.

The fifth thoracic somite was not marked out; the antennulae extend a little beyond the end of
the abdomen. The antennae are practically like those of the female of the preceding stage, but the
Li of Ri has 6 setae; the Ri in the male, which has 6 setae in Le, is not distinctly longer than in the
female. The Re of the maxillnlae possess as usual in this stage 9 setae only. Theyfrj/ pair of legs
has as usual Re I — III completely fused; the Se Re I is much longer than Se Re II; the secretory
pore in the outer margin of Re II is wanting; while that in the outer margin of Re III is well deve-
loped; the pes II — IV show the usual differences; the inner margin of the second basipodite of the
fourth pair of legs is smooth in both sexes; glandular pores are in pes III— IV found at the base of
Se Re I and at the base of Se 3 Re III. The fifth pair of legs is very similar to that of E. rostrata,
but the endopodites are comparatively longer, and the Re dext. is more elongated with fairly long St.
(text-fig. 33 i).

Occurrence. The S/S Thor has gathered this species in six samples viz:

"/; 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire i y? (V).

'5/6 1905 St. 82 5i°oo L. N. ii°43 L.W. Yt. 1200 M. Wire 6 y? (V), 6 yj" (V).

Yt. 800 M.Wire i yc? (V).

"/„ 1905 St. 167 57°46 L. N. 9°55 L.W. Yt. 1500 M. Wire i f?, i y? (V), i yc? (V).

378 — — — — Yt. 300 M. Wire 2 f d".

s/6 1905 St 72 57°52 L.N. 9°53 L.W. Yt. 1500 M.Wire 2 f ?.

^°/6 1905 St. 88 48°09 L. N. 8°30 L. W. Yt. 300 M. Wire 4 f ?, i y? (V), 6 y 5 (V), 5 yd" (IV), 4 y? (IV).

Distribution. This species is recorded from five stations on the west coast of Ireland at depths
of from 350 to laDO fathoms; it has been taken at a great depth by the Gauss Expedition in the South-
Atlantic as far south as c. 35'' L. S. (5° L. E.), and in the Malay Archipelago by the Siboga Expedition.

Remarks. In spite of small differences, partly enumerated above, this species is certainly iden-
tical with that described by Wolf en den. I think that the described male is most naturally referred to
this species in spite of the comparatively small size, fairly long rostrum and rounded lateral corners of the
thorax, and especially on account of the shape of the frontal crest and the well developed accessory
teeth in Se Ri I of pes III— IV.

COPEPODA 1,1

36. Euchirella bitumida n. sp.

(PI. V figs 9a— g; PI. VIII figs 4a— e; text-fig. 34.)

Description, f?. Size of specimen from Thor St. 82 6-6 mm.; anterior division 5-4; nrosome 1-2.
Another specimen measured about 7 ram.

The head is produced into a prominent rounded hehnet-shaped crista (PI. VIII fig. 4 a), like
that of E. galeata, which is well marked off behind, and not continued into a dorsal keel; below the
crest the margin falls steeply towards the prominent but rather short rostrum. The body is rather
slender, with the head and the first thoracic tergites coalesced ; the fifth tergite is not distinctly marked
out, and the lateral corners are rounded (figs ga— b). The anterior division is 4-5 as long as the abdomen.
The genital somite has in dorsal view a better marked convexity on the right than on the left side,
and possesses, slightly in front of middle on each side, a rounded protuberance, bigger on the right
side and with a shallow impression between tlie two; the genital somite is in lateral view rather cha-
racteristic, partly on account of the ventral outline which is suddenly produced in front and falls rather
smoothly behind ; in ventral view it appears rather simple (fig. 9 c). The caudal rami are about as
long as wide; the terminal setae, which are somewhat longer than the interior one,
are of almost equal length and a little shorter than the abdomen.

The antennulae, which almost extend to the end of the abdomen, have the

appendages completely like those of E. messinensis^ and the measurements almost alike,

except segment 17, which is the longest segment, a little longer than segment 19.

The antennae (PI. VIII fig. 4a) have the endopodite one third as long as the exopodite;

the endopodite has 6 setae of equal length in the Le and 6 in the Li, of which the

two inner are rather short. The 7naxillulae differ from those of E. niessinetisis by the ^ ^ ,■

^ Text-fig. 34.

relative length of the setae in Le; the two first and the fifth one are distinctly Eu<:/t.6itumidan.sp.

shorter than the others. The maxillae are, as seen in fig. q d, in main features like , .'

' 071 tenor view X 57-

those of E. messincnsis. The viaxillipeds have the exterior margin of the third basi-

podite, which is 1-3 as long as Basip. I <n> II and about twice as long as Ri, somewhat sinuated; the Ri II

has only 3 setae.

The Jirst pair of legs (fig. 4 b) has a small pore in the almost straight margin of Re II, and
a very indistinct one placed near the base on the outer margin of Re III. The Se of Ri I (fig. 4 c) of
the undivided endopodite in the second pair of legs is poorly developed, as seen in fig. 4 c, and the
Se of Re II extends slightly beyond base 01 Se i Re III. The accessory tooth of Se Ri I is only in-
dicated in the third pair of legs (fig. 4 d). The fourth pair of legs has on the posterior surface of
the second basipodite in the type specimen on the left side a single straight, fairly strong spine, which
almost extends to the base of the third basipodite, and on the right side is substituted for by 3 more
slender spines (fig. 4 e); in another specimen the spine was wanting on the right side; in a third specimen
a single spine was observed on the left side, while none was observed on the right side (perhaps
broken?); in two specimens a single spine was observed on both sides, and in a single one a spine
on the left and one on the right side.

The number of glandular pores is like that of E. messincnsis with a pore in Re I of pes III — IV.

17*

132

COPEPODA

The main difference between E. viessi?ie7isis and this species, found in the structure of the labruni,
is observed in the 2 first groups of the oral surface (fig. g e), which are fused to a single group consisting
of numerous short spinules. The lamina labialis (fig. gf) is distinctly granular; the arrangement of setae
in front of the lamina as well as of the spinulous areas behind it is in the main like that of E. messi-
ncnsis. The development of the series of setae behind and upon the labial lobes is, as seen by com-
paring figs 9 g and 5 g (PI. IV), most like that of E. maxima.

Y^ (St. V). Size of female from Thor St. 88 was 4-66 mm. ; anterior division 3-85 mm.; urosome
o-8i. A male from the same sample measured 4-99 mm.

The shape of the body is as in the adult female; tlie antennulae extend slightly beyond the
end of the abdomen. The antennae are in the joung female, .scarcely different from those of the adult
female but in the young male the exopodite is twice as long as the endopodite, which is niucli more
powerful and has 7 setae in Li.

The second basipodite of the fourth pair of legs has in the middle on the inner margin 3 rather
short and stiff hairs, while the margin is smooth in the male. The fi/tJt pair of legs in the male is
very much like that of E. mcssincnsis (cf. text-fig. 34), but the Re dext. is more regularly rounded, and
does not possess any terminal hair.

Occurrence. The Thor has gathered the species in four samples; the first locality is not quite
certain, owing to a mistake.

V9 1904 St 285 62°49 L. N. i8°46 L. W. Yt. ? Wire i f ?.
'5/6 1905 St. 82 5i°oo L.N. ii°43 L. W. Yt. 1200 M. Wire 6 f ? (i with spermatophor), i y? (V).

800 M. Wire i f?.
2% 1905 St. 88 48^09 L. N. 8°3o L. W. YL 300 M. Wire 2 f?, 2 y? (V), i y^ (V).

Remarks. This species, of which I was not able to find any description in the literature, is
nearly related \.o E. mcssincnsis; in the shape of the head it provides some similarity to Giesbrecht's
rather imperfect description of E. galeata, but his fig. 22 (Taf. 36) of the genital somite is very different.

37. Undeuchaete minor Giesbr.
(PI. V figs 3a-g; text-figs 35a-g.)
1856? Uiidina plumosa n. sp. Lubbock, p. iS, pi. IX figs 3— 5. 1904. Un(leucha?te minor Giesbr. Cleve p. 198.

1SS39. Euchsete pulchra Lubb. Brady, pp. 63— 64, pi. XIV figs

6-9.
— australis n. sp. Brady, p. 65, pi. XXI figs. 8-9
Undeuchre^te miuor u. sp. Giesbrecht, p. 335.

— — Giesbr. — p. 228,pl. I4and37.
Euchsete australis Brady Th. Scott, p. 58, pi. VI fig. 23.
Undeuchaete minor Giesbr. Giesbrecht, p. 251.

— — — Canu, p. 424.

— — — Giesbrecht & Schmeil, p. 34.

— — — Thompson & Scott, p. 244.

— ~ — Wolfenden, p. iii.

1889.
1S92.
1893?

1895.
1S96.
1898.
1903.
1904.

1905-

1906.
1907.
1 90S.
1908.
1909.

1911.

— — Esterl}', p. 149, fig. 17.
— Farran, p. 35.

australis Brady. G. O. Sars, p. 4.
minor Giesbr. Pearson, p. 15.

— — G. O. Sars, p 3.

— — Farrau, p. 37.

— — V. Bremen, p. 44, fig. 50.
plumosa Lubb. A. Scott, pp. 62—63, pi- XXII

figs 1-8.
minor Giesbr. Wolfenden, p. 244.

Description, f^. Size of specimen from St. 88 was 4-65 mm.; anterior division 3-68 mm.; uro-
some 0-97 mm. Giesbrecht's specimens measured 32, Farrau's 4-2, and A. Scott's 3-5— 4-5 mm.

COPEPODA

^33

The strong and short rostrum (text-fig. 35 a) is directed forwards and downwards. The lateral
corner of the thorax is triangnlarly pointed on the left side and rounded on the right (text-figs 35 b— c).
The first abdominal somite is as described by Giesbrecht asymmetric, and possesses on the right
side, dorsally, a strong curved spine; on the left side at the posterior margin we find in most specimens
two vertical rows of from 4—10 teeth, placed the one above the other; on the right side a more regular
row of teeth is observed. The structure of the vulva seems to be rather simple (fig. 3 a). Only in a
single specimen was there found on the left side of the third abdominal somite near the hinder margin
a structure somewhat like the hairy cumulus, which

' .1 be

was figured (Taf. 37 fig. 55) by Giesbrecht. In
a single specimen a moderately long slender seta
was observed in Re I of the antennae. In the lobe
IV of the second basipodite in the maxillipeds no
sensory process was observed. The first pair of
legs has no Se Re I, but Se Re II extends almost
to the base of Se Re III; the articulation between
Re I and II is fairly well marked except anteriorly
and medially. The lateral margin of Re II has a
glandular pore near the base of Se Re II, and that
of Re III has one placed near base. The Se Ri I
has a well developed accessory tooth in pes II, and
a somewhat smaller one in pes IV; the inner margin
of the second basipodite is smooth in the fourth
pair of legs. Glandular pores were found in Re II
and in Re III at the base of Se 3, and in pes III
— IV as well in Re I.

The lateral outline (text-fig. 35 a) of the la-
bruni is somewhat similar to that of Euchczte. Be-
hind the transverse chitinous list, which is placed
somewhat behind the insertion of the antennulae,
alow hairy elevation is found; this is separated by
a depression from the well raised labrura proper.

On the said elevation a median group of long setae and on each side lateral ones of short setae are
observed. Along the posterior margin of the labrum long setae are placed in the middle, and shorter
spine-shaped ones laterally. The oral surface of the labrum is very similar to that of U. major (cf. fig. 2 a),
but the number of setae in the first group is somewhat larger. The lamina labialis and the two series
of setae in front of it are in the main like fig. 2 b, but the number of setae is larger; the arrange-
ment of hairs on the labial lobes and behind is similar to fig. i c.

fj*. Size of specimen from Thor St. 90 was 3-93 mm. ; anterior division 2-89; urosome 1-04 mm.
A.Scott's specimens measured 3-2 — 3-6 mm.

The rostrum is straight and directed directly downwards; the head is raised but has no frontal

Text-fig. 35. UiideuchcEte minor Giesbr.
a. f9. Head X 33. b— c. f9- Left and right lateral corner
X 33- d. fd*. Head X 39- e- fd"- Abdomen X 39- f' ^c?-
Pes V. Ri sin X 59- g- y cf (.St. V) Pes V in ant. view X 59-

134

COPEPODA

keel. The body is rather slender and in dorsal view somewhat attenuated towards the front; the lateral
corners are rounded (text-figs 35 d — e). The abdomen, which is at least one third as long as the an-
terior division, is long and slender. The genital opening is placed on the left side; the fifth somite is
scarcely visible from above; the caudal rami are short (only half as long as the fourth somite, rounded
and about as long as wide). The terminal setae are distinctly longer than the abdomen, and the Si is
one fourth as long as St. 2.

The atticnmilac extend about to the end of the third abdominal somite; the segments 8 '^^ 9 are
partly fused with 10, and 12 with 13, but the segments 20 and 21 are well separated on both sides.
The measurements are very like those of the female; the appendages are practically like those of
Aetidius. The antennae are scarcely different from those of the female; the manducatory part of the
mandibulac is well developed and rounded, but soft-skinned, without any teeth, while the terminal setae
of the palps are more powerful than in the female. The niaxillulac have no setae in Li i — 2, but 3
in Li 3; the number of setae in the third basipodite and the Ri is as in the females, but they are more
slender. The Re has 10 powerful setae, which were all of equal length. The maxillae form an angle-
shaped soft-skinned organ, in which distally soft-skinned, irregular twisted appendages are found. In
the second basipodite of the maxillipcds two setae are found in the fourth lobe; the third basipodite
is enlarged basally, and attenuated towards the end; the setae of the endopodite are fewer in number
and less powerful.

The^ Jirsl pair of legs has a well developed articulation between Re I — II, and the Se Re II is
short and strong, and far from reaching the middle of following segment; in other respects the natatory
legs are scarcely different from those in the female.

The right leg of t\i& Ji/th pair (fig. 3 b) has a short second basal segment, which is fused with
the corresponding one of the left side, and is strongly produced outwards, and a much longer and wider
third basal segment. The right endopodite (fig. 3 e), which extends to the end of Re I 00 II, is rather
elongated, distally slightly curved and, as shown in fig., somewhat hollowed; its anterior surface is
distinctly striated, and marginally we observe a basal tooth, followed by a distinct striated keel, which
is most elevated in the middle (figs 3 c and e). The Re I <n> II of right leg, which are almost completely
fused (figs 3 c — d), have in the proximal part the inner surface striated, and the outer one mounted with
a few rounded rudimentary teeth, followed by an elongated lamina, and lastly a distinct tooth ; the distal
portion (Re II) is somewhat attenuated, and has medially a somewhat contorted, irregular lamella; the R III,
which is comparatively short, has its inner surface somewhat excavated, and has the posterior inner margin
lamellous. The le/t leg (fig. 3 b) has a short second basal segment, but a long and wide third one; the
left endopodite (text-fig. 35 f) is long and slender, reaches distinctly beyond the middle of Re (not seen
in fig. 3 b), is widest at the base and is distally enlarged to a rounded lamella (text-fig. 35 f). The left
exopodite has a fairly short, somewhat curved Re I, a rather short Re II which terminally possesses
a strong spine bearing a basal accessor}' tooth (fig. 3 f), and a moderately long Re III, which possesses
a long terminal seta and a group of fairly long setae anteriorly and interiorly; the last segment is
laterally connected with the Re II by a real articulation, but medially by a wide, soft membrane of a
somewhat complicated structure.

COPEPODA 135

Y^ (St. V). Size of specimen from Thor St. 88 was 3-16 mm.; anterior division 2'5i mm.; urosome
0-65 mm.

In the shape of the body etc. it is scarcely different from the adult female, but the lateral
corner of the thorax is more pointed, showing, however, a similar difference between a more pointed
left and a more rounded right corner. In one of five females a strong spine, similar to that of the adult,
directed upwards and slightly backwards was found dorsally near the posterior margin of the first ab-
dominal somite on the right side; in two other specimens the spine was represented by a single tooth, or
a few only; along the posterior margin of the second abdominal somite no short teeth were found. The
appendages are in the main like those of the adult females; the Re of the maxillulae possess as usual
only 10 setae, of which the median are the shortest; the Se of Re II pes I is shorter than in the adult
female, but longer than in the adult male, reaching somewhat beyond the middle of the following seg-
ment. The male is always easily distinguished from the female by the presence of a rather short and
clumsy fifth pair of legs, of which the left is the longer (text-fig. 35 g).

Occurrence. The Ingolf Expedition has taken 2 females, of which one with spermatophore.

1^5 1896 St. 47 6i°32 L. N. i3°4o L. W. V 100— o fathoms. Temp, at surf. io-6° C.

The Thor has gathered it at the following stations:

1V7 1904 St. 183 6i°34 L. N. i8°43 L. W. Yt. 1800 M. Wire 7 f ?.

'5/6 1905 St. 82 5i°oo L.N. ii°43 L. W. Yt. 1200 M.Wire 3 f ?, i fc?.

29/8 1905 St. 164 6i°2o L. N. ii°oo L. W. Yt. 300 M. Wire i f?.

76 1905 St. 72 57°52 ly. N. 9°53 L. W. Yt. 1500 M.Wire 11 f? (one with 4 sp.).

2% 1905 St. 88 48^09 L. N. 8°30 L. W. Yt. 300 M. Wire 90 f ? (35 with sp.), 2 f d", 4 y? (V), 6 yd* (V).

76 1905 St. 90 47°47 L. N. 8°oo L. W. Yt. 300 M.Wire 125 f? (85 with sp.), 36 fc?, 3 y?, 5 yc?.

Distribution. This species seems to have a world-wide distribution. It has been recorded from
the warm area of the Faeroe-Shetland channel, from the west coast of Ireland as far north as 54° L. N.
"at depths of from 400 to iioo fathom.s". It has been taken by the Monaco Expedition and by the
Gauss Expedition in the Mid- and South Atlantic as far south as 35° L. S. By the Siboga Expedition
it was found rather common in the Malay Archipelago; it was recorded by Giesbrecht from the
Pacific (6°20 L. N. 166—173 L. E.) and by Esterly from the Bay of California.

Remarks. In spite of a few minor differences I am fairly convinced that this species is identical
with that described by Giesbrecht. Though Scott's fig. 8 PI. XXII is wanting in details I think his
male is identical with that described here. Scott is possibly right in identifying Lubbock's Undina
pl/iiiiosa with this male, in spite of minor differences, especially in the structure of the right fifth foot,
which may, however, be due to a mistake; as Lubbock's description is rather incomplete, I do not at
present accept the name U. pluniosa.

I think Scott is right in referring the female of Brady's Eiichcete pulchra Lubb. to U. minor.
As far as I understand Scott, he refers Brady's Euchaie pulchra $ and his E. australis ? to the same
species, but when we compare Brady's fig. 5 PI. 21 and fig. 6 PI. 14, it is easily realised that the two
animals are probably not identical, especially on account of the different shape of the genital somite. I

136

COPEPODA

think the similarity with the other species of this genus, as pointed out by Giesbrecht as far as U.
major is concerned, is better marked, but it may just as well be a species not yet rediscovered. A. Scott
also regards the male of Brady's E. australis as identical with this species, and so does Sars; Brady's
figs 8 —9 PI. XXI show that it belongs to an Uudcjichcetc^ but is far too incomplete for the drawing of
further conclusions.

38. Undeuchaete major Giesbr.
(PI. V figs 2 a— d; text-fig. 36).

1883? 9. Euchseta australis n. sp. Brady, p. 65. pi. XXI figs 5 — 11. j 1905. Scolecithrix cristata Giesbr. Farran, p. 35.

9. — — — Esterly, pp. 147 — I48fig. 16.

Chirudina angulata n. sp. G. O. Sars, p. 13.

Undeuchtete major Giesbr. Pearson, p. 15.

— — G. O. Sars, p. 3.

— — — Farran, p. 37.

9. ^ — — — V. Breenien, p. 43. fig. 49.

18S8. Undeuchaete major n. sp. Giesbrecht, p. 335. I903'

1892. — — Giesbr. Giesbrecht, p. 227, pi. 37. 1905.

1895. — — — — p. 251. j 1906,

189S. — — — Giesbrecht & Schmeil, p. 34. ' 1907

1900. — — — J. C. Thompson, p. 278. 1908.

1903 <S- Scolecithrix cristata Giesbr. J. C. Thompson, p. 21, pi. 1908,

III figs 1—5. 1909.

1904. — — — Wolfenden, p.m. 191 1
1904. — — — Cleve, p. 1 98.

A. Scott, pp. 61—62.
Wolfenden, p. 243.

Description. i% Size of female from Thor St. 90: 4-92 mm.; anterior division 3'9i ; urosome
1-04 mm. Giesbrecht's specimens measured 4-5 mm. and Scott's 4-8— 64 mm.

The lateral corners of the thorax are asymmetrical in a similar way as in Und. minor \ on the
left side it is triangularly pointed, more so than shown in Giesbrecht's fig. 5a (Taf. 37); on the right
side it is more rounded, and bears a small conical process just in front of the end. The oblique hinder
margin has two groups of short spines.

The antennulae are like Giesbrecht's description, but the measurements are somewhat dif-
ferent; the segment 17, f. inst, is scarcely, not distinctly, twice as long as the segment 12. The mouth-
appendages are scarcely different from Giesbrecht's description. The natatory legs differ in a few
minor points from those of U. tnmor\ the Se Re II in the first pair of legs extends somewhat beyond
the middle of Re III, but does not reach the end of it; the accessory tooth of Se Ri I of pes II, which
was just indicated in the preceding species, is fairly distinct. The inner margin of the second basi-
podite of the fourth pair of legs is not quite smooth, but finely undulated, and the posterior surface
possesses near margin just above the insertion of Si from one to four closely placed short spines.

The labruin is in lateral view like that of the preceding species. The oral surface of the
labrum (fig. 2 a) shows a structure similar to that of Cliiridina Street si (fig. 4 b), though less complicated;
the Jirst group consists of about 25 short hairs, placed in an oblique row; the second to the Jifth
groups possess a regular median row and a more or less irregular lateral portion. The transverse rows
of setae are very regular. The chitinous framework is well developed. The lamina labialis, as seen
in fig. 2 b, is distinctly divided into three divisions, and is distinctly striated; in front of the lamina a
median slightly curved series of about 20 setae is found, and a lateral one of numerous setae, of which
the posterior ones are rather delicate. Behind the lamina 4 spinous areas are found on each side, of
which the first one is almost obsolete. The arrangement of the setae upon and behind the labial lobes
differs from that of following species by the comparatively few and long setae in the second series.

COPEPODA

137

f(^. Size of specimen from Thor St. 90 4-92 mm.; anterior division 3-59 mm. ; nrosome 1-33.

The head is, as in the female, mounted with a distinct frontal keel; the body is more slender
than that of the female and even more so than that of the preceding species. The lateral corners are
regularly rounded. The St. 2 of the caudal ramus is longer than the urosome. The antennulac
extend about to the middle of the abdomen. The mouth-limbs are like those of the preceding
species, but soft-skinned, short rounded appendages were observed in the Li I — 11 of the max-
illulae, and the appendages of the maxillae are better developed. The pes I shows the same
difference as in U. minor, and the second basipodite of the fourth pair of legs is smooth.

The fifth pair of legs differs from that of U. vtinor by a few features only ; the Text-fig. 36.
inner margin of the Ri dext. (fig. 2 c) has basally a distinct tooth, followed bv a lamina Undeuciate

° \ o / ^ ^ major Giesbr.

with •&. distinct process in the middle, in shape different from that of the preceding species; fcf. PesVsin.
the outer margin of Re I dext. has a rather low keel, but no distinct teeth. The Re III
sin. (fig. 2 d) differs by shorter terminal seta and by the different arrangement of the setae. The left
endopodite is more slender (text-fig. 36).

Y$ (St. V). Size of female from Thor St. 82 4-95 mm.; anterior division 3-91 mm.; urcsome 1-04 mm.

The shape of body with the frontal keel is scarcely different from that of the adult female.

The Se Re II in the first pair of legs is not shorter than in the female; the inner margin of
the second basipodite in the fourth pair of legs is completely smooth.

Occurrence. The S/S Thor has gathered this species at three stations only:

•5/6 1905 St. 82 5i°oo L. N. ii°43 L. W. Yt. 1200 M. Wire i f? (with sperm.), 2 y? (V).
2% 1905 St. 88 48°09 L. N. 8=30 L. W. Yt. 300 M. Wire 55 f? (13 with sp.).
^Ve 1905 St. 90 47°47 L. N. 8°oo L. W. Yt. 300 M. Wire 25 f? (5 with sp.), 5 i^.

Distribution. This species was recorded by Farran "on every station of from 350 to 1000
fathoms and in 16 out of 34 gatherings, generally in moderate numbers" on the west coast of Ireland
as far north as 54° L. N. It has been met with during the Prince of Monaco's cruises in the East
Atlantic and was recorded as rather numerous at several stations in the South Atlantic even south
of Africa at about 40° L. S. 35° L. E. by the Gauss Expedition.

It has been recorded by Ester ly from the Gulf of CaHfornia, by Giesbr echt from the
Pacific (L.N. 20 L. E. 173) and by Scott from the Malay Archipelago.

Remarks. In spite of the few differences enumerated above, I do not doubt that niy Atlantic
specimens are identical with Giesbrecht's from the Pacific.

A. Scott is certainly right in determining the male referred by Esterly to this species as a
species oi Euchcete, as well as in regarding the male of T h o m p s o n ' s ^tWrny/zr/jc <:m/'«/fl' as belonging
to this species.

39. Undeuchaete superba n. sp.
(PI. IV figs 6 a— b; PI. V figs i a— c; text-figs 37 a-f.)

Description, f?. Size of specimen from Thor St. 183 was 6-42 mm.; anterior division 5-11 mm.;
urosome 1-31 mm.

A rounded, rather low, but fairly prominent frontal keel is found; the undivided rostrum is short,
but strong (text-fig. 37 a). The head and the first tergite are fairly well separated ; the fourth and fifth

18

The Ingolf-Expedition. III. 4.

138

COPEPODA

thoracic tergites are completely fused. The right lateral corner of the thorax (PI. V fig. i a) is fairly
regularly rounded and somewhat shorter than the left one, which is triangularly produced and some-
times shows trace of bifurcation (fig. i b).

The abdomen is about one fourth of the anterior division; the genital somite is a little deeper
than wide and long; on the right side it has a strong, fairly long spine, directed upwards and back-
wards (fig. I a; te.xt-fig. 37 b); in the middle it is strongly produced, and has on the right side of the
vulva a strong spine directed backwards. Along the hinder margin of the third somite ventrally short
triangular teeth are found; they seem to be wanting in the other somites. The caudal rami are distinctly
wider than long; the terminal setae are at least as long as the abdomen, and the Si is one third as
long as St. 2.

The antennulae extend almost to the end of the fourth abdominal somite. The Re of the
antennae is 17 as long as the Ri. The iiiaxillulae have in Le the S i — 3 of moderate length, the S 4
somewhat longer and the S 5 — 9 much longer, but of almost equal length; the Re has, as in the two
preceding species, the median setae distinctly shorter than the others, but not in so marked a degree.
The maxillipcds, in which the comparative length between Basp. i cv; 2, Basp. 3 and Ri is as 30 — 52 — 13,
have the setae of Ri even better developed than in the preceding species, so far resembling the
corresponding limbs of Euchcete. The mandibulac and maxillae are scarcely different from those of
U. major.

The first pair of legs has the articulation between Re 1 and II almost obsolete; the Se Re II
extends distinctly beyond the middle of Re III, but scarcely to the end of it. The secotid pair of legs
has a fairly well developed accessory tooth in Se Ri I (text-fig. 37 c), and the St. has 45 — 50 serrations.
The Se of Ri I in the fourth pair of legs has a distinct pointed accessory tooth, even better developed
than the more rounded one in pes III; the inner margin of Basp. II is somewhat undulated, and
has on the posterior surface, in a similar position as in the preceding species, five short spines (text-
fig. 37 d). The glandular pores are as in the other species.

The anterior coecal sac seems to be wanting. The lateral outline of the labrum is not quite
like that of the two preceding species; the anterior elevation, which on each side possesses about
two groups of long .slender hairs, forms an obtuse angle with the labrum proper; this is on each side
in front beset with a small number (about 50) of short hairs.

The oral surface of the labrtim is like that of U. major (fig. 2 b PI. V), but shows similarity to
that of Ch. Streetsii by a larger number of setae; the lateral group of setae, f. inst, consists of 30—40
short spines, and the first group of the longitudinal series has two instead of a single row. The la-
mina labialis and the area in front of it are scarcely different from those of the preceding species. The
series of hairs behind and upon the labial lobes is rather characteristic as shown in fig. i c (PI. V). The
series I consists of a single oblique row laterally placed; the series II is represented by a large median
and posterior group of short hairs; the series III seems to be represented by a fairly big group in the
middle, almost fused with the corresponding portion of the opposite side, by a more lateral group partly
fused with the fourth group and by two oblique rows on the labial lobe; the series IV consists of a
median group fused with the third and fifth series, and of a rather short row on the labial lobe; the
fifth series consists of a median group and a lateral row.

COPEPODA

139

fj". Size of specimen from Tlior St. 183 was 5-35 mm.; anterior 4-08 mm.; urosome 1-27.

The rostrum and the frontal keel are scarcely different from those of the adult female. The
body is more slender, and the lateral corners are rounded and symmetrical. The abdomen is scarcely
different from that of the two preceding species. The antennulae extend about to the end of the third
abdominal somite, and are also in other respects similar to those of the preceding species. The aniennae
are practically like those of the female, but in the Re I a small conical process was observed medially,
apparently bearing a delicate seta. The manducatory portion of the viandibtilae possesses posteriorly
one or two rudimentary teeth. The maxilhilac have short soft appendages in L,i i — 2; the Le has 2
short and 6 long setae, and the 10 setae of the Re are as usual in the male not shortest in the
middle; the Li 3 has 3 setae, and the Basp. as well as Ri have a similar number of setae as in the fe-
male, but they are softer. The maxillae and maxillipcds are scarcely different from those of the preceding
species. The Jirst pair of legs has as usual a well developed
articulation between Re I — II, and the Se Re II is compara-
tively short; the pes II— IV are scarcely different from those
of the females.

The right leg of the fifth pair has the basal seg-
ments like those of the preceding species (cf. fig. 3 b PI. V).
The right endopodite is in general shape very much like
that of U. minor (figs 9 a— b PI. IV, cf. fig. 3e PL V); it is
terminally somewhat curved and has here lamellar margins,
turned over to establish a gutter-shaped excavation facing
forwards and outwards. Outwards and backwards a well
developed conical tooth is found near the base, and beyond
this, removed one third of the length of the segment from

the base, another striated tooth or elevation is found, which „ ^,, , . , ^r • * • -^ j.

' ' Pes IV basipod. II in post, view X 150. e. ycJ

really forms the middle of the marginal, here scarcely (St. V). Pes V ant view x 33- Ycf (St. IV). Pes v

ant. view X 59-
indicated, keel present in the two other species; the anterior

surface of the endopodite is distinctly striated. The first segment of the right exopodite (figs 6 a— b)
is basally and in front produced into a wing-like expansion bearing three serrations, which are followed
by a low keel and, somewhat more distally, a well developed tooth, where in the typical specimen a
soft-skinned parasite, divided into three globules as seen in figs, is fastened; the second segment, which
is almost completely fused with the first, has distinct marginal lamelli-form expansions; the third seg-
ment is elongated, somewhat attenuated and includes a gutter-shaped excavation facing inwards.

The basal segments of the left leg are in main features like those of the preceding species;
the left endopodite, which extends distinctly beyond the middle of Re I, is elongate and attenuated
with undulated margin; the first segment of the exopodite is less robust and somewhat shorter than
the third basipodite, and somewhat convex; the second segment is short, about 1-5 as long as the
strong curved tooth, which has a distinct accessory tooth; the third segment is similar to that of the
preceding species, but the terminal spine is distinctly articulated.

Text-fig. 37. UndcitchiEte supevha n. sp.

a. fp. Head X c. 30. b. fO- Abdomen X 9-

c. fQ. Pes II Ri I sin in ant. view X 15°- d- f?-

18*

140

COPEPODA

The elevation in front of the labrnm is well developed but smooth. The labnim is rudimentary
without distinct setae, and so is the area labialis; both are soft-skinned with ringed chitin. Lateral!)'
we observe one to two groups of very short hairs.

Yo (St. V). Size of female from St. 167 Thor 1905 was 477 mm.; anterior division 3-80 mm.;
urosome 0-97 ram. A male from the same station measured 4-88 mm.

Shape of body, but for four abdominal somites and more triangularly pointed lateral comers of
the thorax, is like that of the adult female. The Re I of the antennae apparently bears a setigerous
process like that of the adult male; the other appendages do not show features of interest.

The only difference between the males and females is found in the presence of the fifth pair
of legs, which, as shown in text-fig. 37 e, has a rather characteristic structure.

Yq (St. IV). Size of male from St. 183 was 3-28 mm.; anterior division 270 mm. ; urosome 0-58
mm. Size of female from the same station 3-1 mm.

The frontal keel is lower, and the lateral corners of the thorax are less pointed. The mouth-
appendages do not show features of great interest The Re II <^ III of the second pair of legs are
fused, have only 3 Se but the usual number of Si; a glandular pore is only found in Re III at the base
of Se 3; the fourth pair of legs has also a glandular pore in Re I, aud has the inner margin of the second
basipodite smooth. The only difference between the male and female is found in the presence of a
fifth pair of legs with imdivided Re and Ri as shown in text-fig. 37 f.

Occurrence. The S/S Thor has taken a few specimens of this species at several stations.

19/6 1904 St. 152 65°oo L. N. 28°io L. W. i f? (with sperm.), i fcf, i yi (V).

"/6 1904 St. 154 65°27 ly. N. 27°io L. W. i f? (with sperm.).

'% 1904 St. 180 6i°34 L. N. i9°o3 L. W. Yt. 400 M. Wire 2 f ? (with sperm.).

Vg 1904 St. 285 62°49 L. N. i8°46 L. W. i H.

"/; 1904 St. 183 6i°30 L. N. i7°o8 L.W. Yt. 1800 M.Wire 11 f?, 2 fc?, i y? (V), 6 yc? (V), i y? (IV),

I yi (IV).
25/5 1904 St. 104 62°47 L. N. i5°o3 L.W. i f?.

% 1904 St. 286 6i°49 L. N. i4°ii L.W. 2 f?, i yj".

29/8 1905 St. 165 6o°oo L. N. io°35 L.W. i f?.

"/s 1904 St. 99 6i°i5L. N. 9°35 L.W. if?.

Outside the Ingolf area the species has been taken

is/g 1905 St. 82 5i°oo L.N. ii°43 L.W. Yt. 1200 M.Wire if?.

3V8 1905 St. 167 57°46 L. N. 9°55 L.W. Yt. 1500 M.Wire i f?, 3 fc?, i y? (V), i yd' (V).
8/6 1905 St. 72 57°52 L.N. 9°53 L.W. Yt. 1500 M. Wire 6 f ?, i fc?, 2 ^'d".

Remarks. As this species was found not only in the Atlantic south of Iceland, but also in
Denmark Strait and in the Iceland-Fseroe channel, while it was wanting in some of the more southern
stations in which the two other species were found, it is possibly a more northern form.

It belongs naturally to the same group as U. minor and major, though it is well distinguished
from both by combining the right lateral spine of the genital somite and the ventral spine on the

COPEPODA 141

right side of the vulva, as well as by the frontal keel and by the teeth on the second basipodite of
the fourth pair of legs.

This species is even more related to two newly established species, but if the descriptions are
correct, it is scarcely identical with them.

From U. intermedia, which was described by A. Scott (1909 p. 63 — 64; PI. 23 figs 1—8), it differs
by a distinctly raised forehead between the rostrum and the keel, by the different shape and direction
of the two characteristic spines of the genital somite, as well as by a few other characters. From Wolf-
en den's Mesu7ideuch<£tc assymmetrica (191 1 pp. 244 — 245; Taf. 29 figs 4 — 7; text-fig. 28) from the Soil th
Atlantic, which it is very much like in dorsal view, it differs by the structure of the vulva, as the
right spine is wanting in Wolf en den's species. To encompass these species he established a new genus
on account of the teeth of the posterior surface of the second basipodite of pes IV; as the presence
of such spines (cf. Aetidius PI. II fig. i c), even if they are often wanting, is a rather characteristic
feature in the Aetidiidac, and as such spines are found in U. major as well, the foundation is rather
too weak. When all the structural features of males as well as of females are taken into consideration,
it is quite evident that the five species go naturally together.

40. Chirudina Streetsii Giesbr.
(PI. V figs 4a-f; PI. VIII figs, sa-b; text-figs 38 a— k.)

1906. Chirudina Streetsii Giesbr. Pearson, p. 16.

1906. — — — Esterly, p. 59, pis 9, 10, 12, 14.

1908. — — — Farran, p. 37.

1908. — — — V. Bremen, p. 46.

1909. — _ _ A. Scott, p. 43, pi. XII figs

I — II.

1513. — — — Wolfenden, p. 241.

1895. Chirudina Streetsii n. sp. Giesbrecht, pp. 249—250; taf. i

figs 5 — 10.
1898. — — Giesbr. Giesbrecht & Schineil, p. 34.

1902 nee. Euchirella carinata n. sp. Wolfenden, pp. 366—367.
1904? — — Wolf. Wolfenden, pp. T15 — 116.

1904. Chirudina Streetsii Giesbr. Cleve, p. 187.

1905. — — — G. O. Sars, p. 4.

Description, f?. Size of specimen from Thor St. 72 was 5-22 mm.; anterior division 4-18; uro-
some 1-04 mm. Giesbrecht's specimens measured 5-3 mm. Scott's specimens measured 4-8— 53 mm.

The frontal keel and rostrum are well developed, as seen in text-fig. 38 a; dorsally there is trace
of articulation between the head and the first thoracic somite; the fourth and the fifth thoracic tergites
are completely fused, except dorsally, where trace of segmentation may be found. The lateral corners
vary very much in the different specimens; they are more or less rounded, but mounted with a pointed
process, which is sometimes almost wanting, especially on the right side (text-figs 38 b— e), but is some-
times well developed. The genital somite is in dorsal view slightly asymmetrical, as the right outline
is more regularly rounded than the left; the genital area (fig. 4 a), looked at from beneath, is very similar
to that of C. pustulifera, but observed from the side, a fairly prominent anterior protuberance and a
short, sometimes completely covered, posterior one are seen.

The antennulae extend about to the base of the furcal branches; the segment 19, which is the
longest segment, is about 11 as long as 20, which is again longer than 17, the latter being about
II as long as 16; the segment 16 is ri as long as 24^^25. The exopodite of the antennae is 1-5
as long as the endopodite; the second segment of the endopodite has 7 + 7 setae; the first segment
of the exopodite, which is well defined and about one third as long as the second, has a well devel-

142

COPEPODA

oped setigerous process inwards, and the second segment has a similar one at the base in addition to
ones sitting in the middle as well as terminally (text-fig. 38 f). The mandibulae and maxilhilae do not
show any features which were not mentioned in Giesbrecht's description. The maxillae are very
much like fig. 5 c of Ch. abyssalis. The third basipodite of the maxillipeds, which is almost twice as
long as the Basp. \<si2 and distinctly three times as long as the Ri, has along the exterior margin almost

from base to tip on the
posterior surface a low
transparent lamella with
a distinct concavity in the
middle; the fourth lobe
of the second basipodite
is placed posteriorly, and
has a fairly long sensory
lobe surrounded by slen-
der hairs, in addition to
three setae (text-fig. 38 g) ;
anteriorly, and somewhat
removed from the tip, a
rounded protuberance is
found in the second basi-
podite, probably corre-
sponding to that of E. cur-
ticaiida. The first pair of
legs has the inner margin
of the last basipodite
.slightly convex, as seen in
text-fig. 38 h ; the Se of Ri I
has no accessory tooth in
the second pair of legs, and
no trace of it in the third
and fourth pairs (text-fig.
381); the inner margin of
the second basipodite in
the fourth pair of legs is in most specimens completely smooth, but in some has one or two short
stiff hairs corresponding to Giesbrecht's "sparlichen kurzen Spitzen". The glandular pores are like
those of Undeuchate. The elevation in front of the labriim is smooth and fairly well raised; along
the posterior margin the labrum proper has as usual a median row of long and slender hairs divided
into a right and a left part, and a lateral shorter one, of more spine-shaped setae. The oral surface of
the labrum (fig. 4 b) is like that of Undeuchcete. The first group of the longitudinal series is placed
obliquely, and consists of about ten fairly strong setae; the second group consists of two rather inde-

Text-fig. 38. Chirudina Streetsii Giesbr. fQ.

a. f9. Head X 30. b. f$. Abdomen X 18. c. f9. Lateral corner from the right side X 18.

d-e. f9. Left lateral comer X 18. f. fQ. Antenna sin. Re X 57. g- f?. Maxillipes d,ext.

in post, view X 57- h. f9. Pes I sin. X 57. i- f?- Pes IV sin. X c. 20. j. y9 (St. V). Left

lateral comer X 18. k. ycf (St VJ. Pes V in anterior view.

COPEPODA 143

pendent parallel rows; the third group as well as W\^ fourth and fifth has the inner rows of setae
in each group fairly well separated, but has the more laterally placed hairs of each group rather irre-
gularly placed. Behind and laterally to the fifth group on each side a large number of very delicate hairs
are found. The lateral group in front consists of numerous delicate short hairs. The transverse series
around and behind the median circular spot Nr. 4 is shown in fig. 4 b.

The lamina labialis is minutely granular and, as seen in fig. 4 c, laterally prolonged backwards;
the lateral series in front consists, except posteriorly, of a single row; the medial series, in front of which
a minutely granular area is found, is fairly long.

The arrangement of the series of hairs behind and upon the labial lobes is the following (fig.
4d): 'Ca.^ first series is almost longitudinal and consists of 10 hairs; the second series consists of a
group of about 10 hairs; the third scries consists of two well separated transverse rows, well removed
from the longitudinal row upon the labial lobe; in front of the two mentioned transverse rows 2 others
are observed, which probably belong to the fourth series; this is well developed upon the lobe and
has proximally a large group of numerous hairs, partly belonging to the fifth series, which medially
has a transverse row. In at least one of the specimens several of the hairs are slightly clavate. Behind
the transverse line which separates the mandibular and maxillular somites, groups of hairs, as shown
in fig. 4 d, are found.

A short but distinct frontal coecal sac is found.

fc?. Size of specimen from Thor St. 88 was 3-80 mm.; anterior division 2-83 mm.; urosome
0-97. Scott's specimen measured 41 mm.

The frontal keel and the rostrum are (as seen in PI. VIII fig. 5 a), somewhat different from those
of the female. The body is rather slender and attenuated towards the front, but less so towards the
end; the lateral corners are rounded. The anterior division is 3-8 as long as the abdomen, which has the
genital opening on the left side and short triangular teeth along the hinder margin of the second to fourth
somites. The antennulae extend scarcely to the middle of the abdomen; the segments 8<n>9 are almost
completely fused with 10 and 12 with 13, but the segments 20 and 21 are well separated on both sides.
The exopodite of the antennae, which is 1-4 as long as the endopodite, has in the first segment a
single process without setae, and in the second 2 basal processes and a single terminal one. The soft-
skinned manducatory part of the mandibulae has a single well developed tooth and a few rudimentary
ones, and the Ri 2 has 9 Sa, but not, as in female, a Sp.

The maxillulae possess at least 6 soft sensory (?) appendages in Li i; the Li 2 was wanting,
but in Li 3 at least 3, in Basp. 3 at least 3, and in Ri at least 11 setae were found. The Re has 10
well developed plumous setae in addition to a delicate interior one, and Le has 2 short, delicate, basal
setae in addition to 5 distal, long ones. The maxillae (PI. VIII fig. 5 b) have 5 well developed lobes,
of which the fifth one bears a big twisted seta with enlarged base; the endopodite has at least 5 setae.
The maxillipes is more clumsy than that of the female, in shape ressembling that of the males of Und-
euchate; the third basipodite is 1-3 as long as the two first ones and 2-5 as long as Ri; the lob. IV of
the second basipodite has a long, slender seta and a rather short, curved, spine-like one in addition to
the usual conical one.

"TV^ first pair of legs differs from that of the female by the very short Se of Re I; the Se of

144 COPEPODA

Ri I in the third pair of legs has a fairly distinct accessory tooth, but in other respects scarcely any
difference was observed between the natatory legs of the male and female.

The fifth pair of legs is in general structure most like that of UndeuchcBtc 7)iinor (PI. V fig. 4 e),
to the description of which I partly refer. The right endopodite is about as long as the first segment
of the exopodite, enlarged distally and here gutter-shaped; on the posterior surface near the base a
short tooth was observed, and along the outer margin a short and low lamina. The first and second
segments of the right exopodite are completely fused, and have in the middle an obtuse angle open
outwards; the outer margin has proximally two large teeth and a smaller one, and the posterior surface
has, near the end, one or two raised keels; the third segment of the exopodite is gutter-shaped, like that
of U7tdaich(vtc s. s., but has a terminal, well articulated seta, two thirds as long as the segment.

The third basipodite of the left leg has inwards near base a blunt tooth; the endopodite is
slender, projects beyond the end of the first segment of the exopodite, and it distally somewhat hol-
lowed; the second segment of the exopodite is rather short, has the inner surface distinctly hollowed,
and has inwards near the end a strong, rather short spine with a blunt accessory tooth as well as a
rounded process; the third segment of the left leg (fig. 4 f) is similar to that of Undeuchcete, but is less
slender, and possesses a short bristle in addition to the terminal setae, which are distinctly half as long
as the segment

Yp (St. V). Size of female from Thor St. 88 was 40 mm.; anterior division 3-15 mm.; urosonie
0'85 mm. A male measured 4-02 mm.

The shape of the body is in the main like that of the adult male, but the frontal crest is some-
what lower, and the lateral corners are triangularly pointed, and scarcely different on the two sides;
the limitation, between the head and the first tergite as well as between the fourth and fifth ones, is
fairly distinct (text-fig. 38 j). The first abdominal somite is better produced in the male than in the
female. The appendages show the usual differences from those of the adult female; the inner margin
of the second basipodite is smooth in both sexes. The fiftli pair of legs is, as seen in text-fig. 38 k,
fairly well developed.

Occurrence. The S/S Thor has in the Atlantic south of Iceland gathered this species at four
stations viz:

Vg 1904 St. 285 62°49 L. N. i8°46 L. W. 2 f ?, i yd" (V).

"/7 1904 St. 183 6i°3o L.N. i7°o8 L. W. Yt. 1800 M. Wire i f?.

=■4/5 1904 St 180 62°47 L. N. i5°03 L. W. Yt 500 M. Wire i f?, i y? (V).

^78 1905 St 163 63°36 L.N. i2°05 L. W. Yt 300 M.Wire if?.

Farther south the species was in one of five samples taken in big numbers.

'5/6 1905 St 82 5i°oo L.N. 11^43 L.W. Yt 1200 M.Wire i H.

31/8 1905 St 167 57°46 L.N. 9°55 L.W. Yt 1500 M.Wire 5 f ?.

8/6 1905 St 72 57°52 L.N. 9°53 L.W. Yt 1500 M.Wire 5 f ?.

"/e 1905 St 90 47°47L. N. 8°ooL.W. Yt 300 M. Wire 5 f 9.

2°/6 1905 St 88 48=09 L.N. 8°30 L.W. Yt 300 M.Wire 137 f?, 7 f c?, 27 y? (V), 62 yd' (V).

COPEPODA 145

Distribution. According to Far ran "this species is of frequent occurrence in the N.E.Atlantic,
having been taken on every station at depths of from 300 to 1000 fathoms". It has been recorded
from the Fteroe channel, from the Mid Atlantic and from the South Atlantic as far south as 35° L. S.
It has been recorded from the Gulf of California, from the Pacific 35° L,. N. 125° L,. W. as well as from
the Malay Archipelago.

Remarks. In spite of the small differences enumerated between my specimens and Giesbrecht's
description I think the Atlantic and the Pacific forms belong to the same species. Different authors, f.
inst. Pearson and A. Scott, have identified Wolfenden's Euch. carinata ^\W\ this species; they are
certainly wrong as far as the young male described in 1902 is concerned; on account of the frontal crest
like that of E. galeata, the rounded lateral corners of the thorax and the left endopodite of the fifth
pair of legs "like small stump" there is some reason to identify it with, f. inst., Euchirella intermedia
(cf. p. 127). The position of the adult female is somewhat uncertain; Wolfenden regards it (p. 236) as a
true Euchirella in spite of the missing spines of the second basipodite of the fourth pair of legs. It
is with some reluctance that I have referred the described male to this species; at present it is impos-
.sible to tell its certain position. The descriptions of Esterly and Scott are too short for a certain
identification.

41. Chirudina pustulifera G. O. Sars.

(PI. V figs 6 a— d; text-fig. 39.)

1905. Undeuchffite pustulifera n. sp. G. O. Sars, p. 14.

1908. Euchirella Wolfendenii n. sp. Farran, pp. 38— 39! P'- ^ f'gs iS— 19; pi. IV fig. 3.

1908. Undeuchsete pustulifera G. O. Sars. v. Bremen, p. 44.

Description. Size of female from Thor St. 183 was 6-9 mm.; anterior division 57 mm.; urosome
1-2 mm. Sars' specimens measured 6-9 and Farran's 72 mm.

The head has no frontal crest, but a strong, slightly curved rostrum (text-fig. 39). The fifth
somite is well limited in front, and the lateral corners are rounded (figs 6 a— b). The genital somite
has a very characteristic shape (figs. 6 a— b); on the left a low protuberance is found,
and on the right side a very prominent one, consisting of a basal larger portion
and a terminal regularly rounded part. The genital somite, seen from the side, has
a strong, rounded, rather prominent protuberance in front, and a lower one in
the middle as well as behind; observed from below the genital area (fig. 6 c) is like Text-fig. 39. ciurudina
that of Ch. StreetsiL The abdomen is almost everywhere hairy, but the setae are ^""^^'^^^^^^y^ c" ^^^
longest and best developed dorsally along the hinder margin of somites II— IV.

Dorsally in the genital somite as well as ventrally in the third and fourth ones tufts of shorter and
longer hairs are observed. The caudal rami are about as long as wide, and the Si is scarcely half as
long as the St., which is about as long as the abdomen.

The antennulae extend to the end of the abdomen. The antennae are scarcely different from

Farran's fig. 18 PI. XI, except by the presence of a fairly long terminal seta in Re 2; the Re is about

17 as long as Ri. The mandibulae are scarcely different from those of C. abyssalis n. sp. (cf. fig. 5 b);

the third basipodite is not smooth as indicated by Farran, but has 3 setae. The maxillulae have 5

powerful setae in Li 2, have 4 + a conical process in Li 3, and 5 in the Basp. 3; the Ri I— III pos-

19

The Ingolf-Expedition. III. 4.

146

COPEPODA

sess 4 + 5 + 7 setae as in CIi. Strcctsii. The exopodite has 11 setae, of which the median ones are
comparatively short, but not in so marked a degree as in Undeuchcete. The Le has 9 setae (according
to Farran 8 only), of which the third and the ninth are somewhat shorter than the Set. 4 — 8, and
the first and second are much shorter. The maxillae are very much like those of <7//. abyssalis^ cf. fig. 5 c,
and have the hairs on the posterior surface of the four lobes arranged in a similar way. The maxilli-
peds are very similar to those of Ch. Strcelsii, but have no lamina along the outer margin of the
second basipodite, nor the anterior process of the second basipodite; the third basipodite is 1-5 as long
as the first and second, and 3-8 as long as the endopodite.

Th.& Jirst pair of legs has the articulation between Re I and II represented by a fairly distinct
chitinous line, which is almost wanting posteriorly; the Se Re I extends beyond the end of Re II,
and the Se Re II extends just to the end of Re III. The second pair of legs has indication of
articular membrane between the Ri I^II, but has no accessory tooth at the base of the blunt Se Ri I;
the terminal spine has 70 serrations. The Se of Ri I is pointed, but is without accessory teeth in the
two last pair of legs; the second basipodite of \\\& fourth foot bears on the hinder surface of a process
projecting from the inner margin a transverse row of 8— 11 strong, fairly long spines, of which the
inner are somewhat more slender.

The lateral outline of the labruni is like that of Ch. Sfreefsii, with well raised, smooth, anterior
elevation, and so is the oral surface of the labriini (fig. 6 d) ; the only difference of importance is found
in the much longer first group, the almost wanting lateral row in the second group, and the much
better developed transverse row of short hairs in front of the transverse chitinous bar. The lamina labialis
and the area in front of it are scarcely different from those of Ch. Streetsii, while the arrangement of
hairs upon and behind the labial lobes is like that of Ch. abyssalis (fig. 5 f ) ; a tuft of about 20 long
slender setae is found on the lateral surface of the labial lobe, just as in Ch. nofacantha.

Occurrence. The S/S Thor has gathered this species at two stations.

"/? 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 17 f? (5 with sp.).
'% 1904 St 180 6i°34 L. N. i9°03 L. W. Yt. 400 M. Wire i f$ (with sp.).

Distribution. This species has been recorded from two stations between 700 and 1000 fathoms
off the west coast of Ireland; the Monaco Expedition has gathered it at three stations.

Remarks. The only difference found betweeti my specimens and Sars' description, which is
rather insufficient, is found in the comparatively shorter "antennes anterieurs depassant la longueur
de la division anterieure du corps". The Basp. II of pes IV has 6 for 11 spines. The unimportant dif-
ferences from Farran's description are enumerated in the description. Farran has referred the species
to Euchirella, probably on account of the well developed spines in the second basipodite of the fourth
pair of legs, but it differs in a number of more important characters, viz: the structure of the oral
surface of the labrum, the wanting glandular pore of the base of Se i Re III pes II — IV, the compara-
tively long Ri of the antennae, the position of the sj^ines on posterior surface of lobes I — IV of maxillae,
and the arrangement of the setae of the maxillulae. In all these characters it agrees with Chirudina as
well as, though in a less degree, with UiideicchcEte. It agrees with Undeuchcete in the comparatively
short median setae of the Re of the maxillulae, but with Chirudina m the number of setae in L,i 2 and

COPEPODA

147

Ri of the maxillulae and the presence of a Se Re I pes I. The two genera are very nearly related,
but as the five species of Undeuchcete form a very natural group I prefer to refer this species to
Chirudina.

42. Chirudina abyssalis n. sp.

(PI. V figs 5 a— f; text-figs 40 a— c).

Description. i% Size of specimen from Thor St. 183 was 5-4 mm.; anterior divisioii 4-3 mm.;
urosome i-i mm.

The head is gradually rounded in front, without any crest; the rostrum is rather short, but
strong, directed downwards and slightly backwards (text-fig. 40 a). The cephalothorax, which is moder-
ately slender and slightly attenuated towards the front part as well as towards the end, is about 2-5
as long as wide; the first thoracic tergite is, at least dorsally, well separated from the head; the fifth
somite, which is well separated in front,
is laterally not produced, and has evenly
rounded corners (fig. 5 a). The anterior
division is about four times as long as the
abdomen.

The genital somite, which is a
little wider than deep and as deep as long,
is in dorsal outline almost symmetrical;
the ventral surface is anteriorly rather
suddenly produced and posteriorly gradu-
ally sloping; the genital area is in ventral
view seen to be somewhat different from
that of the preceding species. The genital
somite possesses, dorsally, along hinder margin, short hairs, and ventrally tufts of longer hairs ; the fol-
lowing somites are more and less hairy, the hairs being longest dorsally and ventrally. The caudal
rami are about as long as wide; the terminal setae are distinctly shorter than the abdomen and about
three times as long as the Si.

The anienmilae extend to the end of the caudal rami; the measurements are very like those
of the preceding species. The exopodite of the antennae is i-6 as long as the endopodite; the second
segment of the endopodite has 8 setae in Li and 7 in Le; the first segment of the exopodite, which
is one third as long as the second, has inside a short protuberance with a short hair; the second seg-
ment has only a terminal seta. The mandibulae have, as shown in fig. 5 b, a rather characteristic shape,
and the viaxillulae are completely like those of Ch. pustulifera. The maxillae (fig. 5 c) are only
slightly produced basally, and have the spinous areas on the hinder surface of the four proximal lobes
distinctly different from those of \\\o?,'i s^^^ox^s oi Euchirella (cf. fig. gd); in the first lobe a smooth area
is found surrounded by spines. The uiaxilUpeds are scarcely different from those of the preceding species;
beyond the Si 3 in the third basipodite a longitudinal row of longer and shorter teeth is found (text-
fig. 40 c) ; similar teeth were found in Ch. pusfuli/era, but not in C/i. Streetsii.

19*

Text-fig. 40. Chirudina abyssalis n. sp.
a. f 9. Head X iS. b. Pes I X 33. c- Maxillipes sin. Basp. Ill in post.

view X 87.

148

COPEPODA

The. Jirsf pair 0/ legs (text-fig. 40 b) has the articulation between Re I and II better developed
than in the preceding species, but is in other respects scarcely different; the terminal spine of the second
pair of legs has 90 teeth, and the second basipodite of the fourtli pair of legs has 11 knife-shaped
spines (fig. 5 d).

The outline of the labrum is, as seen in text-fig. 40a, somewhat different from that of Ch. Streetsii;
the oral surface of the labrum differs in the same way as that of Ch. pustulifera from that of Ch. Streetsii.
The lamina labialis is smooth, and the area in front of it is, as shown in fig. 5 e, somewhat different
from that of Ch. Streetsii, and so is the arrangement of hairs upon and behind the labial lobes (fig.
5 f), the main difference being that a large group of delicate hairs is found where the series III and
IV start at the base of labial lobes, not where series IV and V start. In front of the oesophagus a
long coecal sac is found.

Occurrence. Of this species the S/S Thor has only taken 4 adult females "/^ 1904 St. 183 6i°30
L.N. i7°o8 L.W. Yt. 1800 M. Wire.

Remarks. This species is very nearly related to Ch. pustulifera.^ and ought, accordingly, to be
referred to the same genus. It shows some similarity to U. obtusa G. O. Sars (1905 p. 13; Farran 1908
p. 40), which has the antennules "depassant a peine, en longueur, la division anterieure du corj^s", as
well as to U. lobata G. O. Sars (1907, pp. 11 — 12), from which it seems to differ by lateral corners "assez
saillants en arriere et etroitement arrondis an bout", by longer abdomen and antennulae.

43. Chirudina notacantha G. O. Sars.

(PI. V figs 7 a-b; PI. VI figs i a— b; text-figs 41 a— k).

1905. Gaidius notacanthus n. sp. G. O. Sars, pp. 9— 10. , 1909. Nee. Gaidius uotacauthus G. O. Sars. A. Scott, p. 52, pi.

1908. — — G. O. Sars. Farran, pp. 33—34. pi. XXI figs 24—32.

Ill fig. 7. I

Description. Y^ (St. V). Size of a young male 572 mm.; anterior division 47 mm.; urosome
1-02 mm. Young females measured from 4-31 — 5-54 mm. Sars' specimen measured c. 5 mm.

The lateral outline of the head is gradually sloping towards the strong imdivided rostrum,
which is directed downwards and slightly backwards (text-fig. 41 g). The cephalosome, which in tlie
middle is scarcely half as broad as it is long, is attenuated towards the front as well as towards the
end. The head is well separated from the first thoracic tergite, and the fifth one is well marked out
in front (text-fig. 41 i); the latter somite is, near dorsal margin, produced into a strong triangularly
pointed spine, which scarcely attains the end of the first abdominal somite. The abdomen, which is
scarcely one fourth as long as the anterior division, has four somites, the comparative length of which
was 22, 29, 21, 17 and 15 (furcal branch); the furcal branch is distinctly wider than long. Along the
hinder margins densely placed hairs are found; the terminal setae are distinctly shorter than the ab-
domen (text-fig. 41 j).

The antennulae extend almost to the middle of the abdomen; in measurement they are very
much like those of Ch. Streetsii. The exopodite of the antennae is almost i-S as long as the endopo-
dite, which has 7 setae in Li and 6 in Le; the first segment of the exopodite has a short process
inside, bearing a delicate seta, only as long as the process itself, and the second has a terminal seta

COPEPODA

149

inside (cf. CIi. abyssalis). The iiiaxillulac have in addition to the 4 Sp. on the posterior surface of Li i
a short S 15; the Le 2 has 5 setae, the Li 3 has 4 setae and the Basp. Ill has 5 setae; the endopodite
has 3 setae in Ri I, 5 setae in Ri II and 7 setae in Ri III. The exopodite has 10 setae of about equal
length, and the Le has 2 short proximal setae and 7 long distal ones. The maxillae are scarcely dif-
ferent from those of C/i. abyssal/s cf. PI. V fig. 5 c, and the maxillipeds have tlie third basipodite 3-3 as
long as the endopodite and
1-6 as long as the two basal
segments.

The first pair of legs
is very much like that of Ch.
abyssalis; the articular mem-
brane between Re I— II is com-
pletely wanting posteriorly
and only slightly developed
anteriorly; the vSe of Re I
distinctly extends beyond the
end of preceding segment,
and so does Se of Re II.
The articulation between Ri
I — II in the second pair of
legs is wanting posteriorly,
but is marked by an indi-
stinct line anteriorly, and the
Se of Ri I is slightl)- marked
as seen in text-fig.; the arti-
culation between Re I and II
is almost wanting posteriorly;
the St. has 50 — 60 short teeth.
The Se of Ri I is well devel-
oped but without an acces-
sory tooth in the fourth pair
of legs, and the inner margin
of the second basipodite is completely smooth. The only difference between the male and female is
found in Wvt fifth pair of legs in the male (text-fig. 41 k); this is distinctly different from the preceding
species by the segmentation of the left exopodite and by the wanting terminal setae. The labritm etc.
is scarcely different from that of Ch. Strcctsii (cf. text-fig. 38 a) ; along the transverse ridge which limits
the labruni in front about 10 rather delicate setae are found. The oral surface of the labrum (PL VI
fig. I a) is rather characteristic, though showing most similarity to that of Ch. Streetsii; the supporting
chitinous framework is less developed. The first group of the longitudinal series consists of numerous
short spinules; the second group consists of a single longitudinal row of fairly long setae; the third

Text-fig. 41. Chirudina notacantha G. O. Sars.

a. fd". Head X 30. b. abdomen etc. X 30- c— d. Pes V dext. Ri-f RelcsslI from

the right and partly from behind X c. 50. e. Pes V Ri sin. X 66. f. Pes V sin. Re

II— III X 75- g. yc? (St. V) rostrum, h— i. (St. Vj fifth thoracic tergite from the left

and from above, j. (St. V| furca X 29. k. (St. V) Pes V in ant. view X 29.

j-Q COPEPODA

io fifth groups consist of au inner more or less longitudinal row of fairly long setae inwards and of
more irregularly placed setae laterally; a sixth group of very short delicate setae is found; the trans-
verse rows are, as seen in figs, like those of Chirudina Strcctsii. The /aiiiiiia labialis (PL VI fig. i b) is
not quite like that of any of the examined species, as it consists, as shown in figure, of two rather
independent portions. The arrangement of the setae in front of the row is like that of Chirudina Strcetsii,
but no granular area was observed. The arrangement of tlie series upon and behind the labial lobes is
in its main feature like that of C. abyssalis (PI. VI fig. i b; cf. PI. V fig. 5 f). Laterally a similar tuft
of hairs is found as in Ch. pustulifera.

fc? (St. VI). Size of specimen from Thor St. 183 was 67 mm.; anterior division 5-2 mm.; urosome 1-5 mm.

The head is rounded, with fairly slender rostral spine (text-fig. 41 a). The body is more slender
than in the female; the articulation between the head and the first thoracic tergite is only indistinct;
the lateral spine of the thorax is placed more dorsally, is more slender and apparently starts from the
fifth somite. The comparatively slender abdomen is about one third of the anterior division, and has, as
seen in text-fig. 41 b, the genital opening on the left side, and has a seam of short, delicate teeth along
the posterior margins of somites II— I V^. The furcal rami are somewhat wider than long; the St. 2 is
somewhat longer than the abdomen. The antennulae extend about to the end of the second abdominal
somite; the segment 10 is partly fused with 8^9, the segment 12 with 13, but the segments 21 and
22 are well separated on both sides; ".i^sthetasken" are only wanting in segments 20, 23 and 24; the
measurements are very similar to those of the young ones. The exopodite of the a?itennae is only 1-3
as long as the endopodite; the Re I and II are indistinctly separated, and both possess a rudimentary
setigerous process, but the antennae are in other respects like the female. The viandibula scarcely
differs from that of Ch. Strcetsii. The inaxillulae possess in Li i at least 10 soft-skinned ringed appen-
dages as well as two short setae of usual structure, in Li II, which is fairly long, 3 soft appen-
dages, and in Li III 5 setae of usual structure are found; the basipodite III has 5 setae, the Ri I — II
have 7 setae, and the Ri III has 7 as well; the exopodite has 10 long setae and a short delicate inner
one, and the Le has 2 short basal ones and 5 long distal ones. The viaxillae are soft-skinned, but they
are better developed than in most other species of this family ; the Lob. I — IV are well developed, and
possess 2 to 3 setae, and so does Lob. V, but its Sp. is strong and not twisted; the Re has 6 setae. The
maxillipcds are in main feature like those of Ch. Strcetsii; their third basipodite is 2-5 as long as Ri
and 1-5 as long as the two basal segments.

The first pair of legs has the articulation between Re I — II better developed, and the Se Re I
is quite rudimentary ; the three last natatory legs are scarcely different from those of the young specimens.

The right fifth foot has a rather short third basipodite; the right endopodite has some similarity
to that of Ch. Streetsii, is terminally gutter-shaped on the anterior surface, but has somewhat proximally
to its end laterally a rounded incision (text-fig. 41 c); the outline of the endopodite is rather irregular, but
no marginal laminae or teeth were observed in proximal half. The right exopodite has the two first
segments fused, and is, observed from in front, distinctly convex towards the middle; the third segment
is obtusely rounded, is rather elongate and possesses marginally a distinct lamina (text-figs 41c— d). The
third basipodite of the left foot is long, almost attaining the middle of Re I cnj II ; the left endopodite
(text-fig. 41 e) is unsegmented, and is, as shown in fig., distinctly narrow somewhat beyond the middle.

COPEPODA i^i

The first segment of the left exopodite is fairly long and slender, while the second, as shown in text-
fig. 41 f, is broad and widened out terminally, where a bifurcate spine is seen ; the third segment (PI. V
fig. 7 a) is distinctly widened out towards the end and produced inwards, where the usual tuft of mar-
ginal setae is observed; on the posterior surface groups of delicate hairs are found. Inwards at the
base of Re III, a partly independent, lobe is observed with groups of fairly long hairs posteriorly.

The outline of the labrum is, as seen in fig., very similar to that of the female, but the whole
apparatus is soft-skinned without any setae, but adorned with an intricate systeme of chitinous ridges;
two labial lobes are present with a longitudinal furrow between.

Parasites. In one specimen twisted structures like those described in Gaidms tcmiispinns
(p. 92) were attached behind both maxillae; in another specimen a similar organ was found behind
the one maxilla only, but in that specimen a "sac-shaped parasite?" was found attached to the L,i I
of the left maxillula.

Occurrence. The Thor Expedition has "/? 1904 St. 183 6i°30 L. N. i7°o8 U W. Yt. 1800 M. Wire
gathered 3 young females, 11 adult males and 9 young males.

The Monaco Expedition has taken immature females at two stations, and Farran has recorded
adult males as well as immature ones from the west coast of Ireland "on four stations from depths of
600 to 1 150 fathoms".

Remarks. I am pretty well convinced that the described species is identical with Sars' Gaidius
notacanthus^ in spite of a few differences from the somewhat meagre description, viz: in the antennulae,
which are not "presque aussi longues que le corps". The male is probably identical with that described
by Farran. The male, which Scott has referred to this species, is 5-9 mm. long and has rounded
lateral corners; accordingly it is not the male of Ch. notacantha^ and it may more naturally be regarded
as the male of Ch. pustulifera. Sars and Farran as well as the other authors have i^rovisionally
referred this species to Gaidius.^ as the adult females are not yet known. Several structural features
have, however, convinced me that this species like CIi. parvispma, and probably also Gaidius validus
Farran (1908, p. 32), G. cryptospinus G. O. Sars (1905, p. 10), divaricatus G. O. Sars (p. 10) and G. niaximus
Wolf. (1906, p. 2), is nearly related to Undeuchate spectabilis G. O. Sars (1900) p. 59 as well as to Clii-
rtidina Streetsii, pustulifera and abyssalis. It differs from Gaidius tenuispimis etc. by the three-seg-
mented exopodite of the first pair of legs with well developed Se Re I, by the wanting setae along
the inner margin of the second basipodite in the fourth pair of legs in the young specimens of the
fifth stage, as well as by the structure of the oral surface of the labrum and the lamina labialis.

All the described males referred to this genus show a marked similarity to Lhideuchcrte in the
structure of the fifth pair of legs, and are accordingly different from those of Gaidius and Gaetanus.

44. Chirudina parvispina Farran.

(PI. V figs 8 a; text-figs 42 a-g and 43 a-h.)

1900? Undeuchcete spectabilis n. sp. G. O. Sars, pp. 59—63, pis XV— XVI.
1908. Gaidius pan-ispiuus n. sp. Farran, pp. 34—35. P'- H figs 4—8.

Description. Y ^ (St. V). Size of young male from Thor vSt. 183 was 5-1 ram. ; anterior division
4-14 mm.; urosome 0-96 mm. Young female measured 4-42 mm. Farran's .specimens measured 4-9 mm.

152

COPEPODA

fv,

The rostrum is strong and directed downwards. The head is, in contrast to Farran's fig. 4,
well separated from the first thoracic tergite. The fifth somite is well developed and bears a short,
downwards directed hooked spine (text-fig. 42). The abdomen differs from that of the preceding species
by being less hairy. The antennulae extend to the end of the chephalosome; the mouth appendages
are scarcely different from those of Cli. iwtacantha. In the strticture of the natatory legs scarcely any
difference was observed between this and the preceding species. The third foot is shown in text-fig.
42 e. The only difference between male and female is found in the presence of a fiftli pair of legs in
the former sex; this pair of legs (text-fig. 42 g) is in most respects like that of the preceding species, but
differs by the equal length of the two exopodites as well as in a few minor points.

In the structure of the labrjtvi and its surroundings no difference of great interest was observed

between this species and the
preceding ones (cf. PL VI figs
I a -b).

Y^ (St. IV). Size of male
from Thor St. 183 was 3-46 mm.;
anterior division 2'8i mm.; uro-
some 0-65 mm.

The body is more slender,
and so is the rostrum; the
lateral corners are somewhat
more robust (text-fig. 43 f). The
abdomen consists of three seg-
ments as .shown in text-fig.
43 f. The mouth appendages
show the usual differences. The
exopodite of the first pair of
legs .shows no trace of segmentation, but has three well developed Se. The endopodite of the srcoiid
pair of legs is unsegmented, and the two last segments of the exopodite are fused, bearing 3 Se and a
single glandular pore at the base of Se 3. The inner margin of the second basipodite of the fourth
pair of legs is smooth. The only difference between the male and female is found in the fffh pair of
legs, which, as shown in text-fig. 43 h, is less developed than in the preceding stage.

f c?. Size of male from Thor St. 183 was 5-28 mm.; anterior division 4-15 mm.; urosome 1-3 nun.

The rostrum (text-fig. 43 a) is somewhat shorter, and the lateral spines of the end of the thorax,

which are placed less dorsally, are more slender and extend a little beyond the hinder margin; the

fifth thoracic tergite is not distinctly marked out. The abdomen (text-fig. 43 b) is scarcely different from

that of Ch. iiotacantha.

The antennulae extend beyond the end of first abdominal somite. The two basal segments of
the exopodites are well separated in the antennae, and the maxillae have the setae of the first lobes
somewhat contorted, and the Sp. of the lob. V more swollen at the base, but in other respects the
mouth-limbs were like those of the male of Ch. notaca/itha.

Fig. 42. Ch. parvispitia Farr. Ycf (St. V).

a. Left lateral corner X 29. b. Third basipodite of uiandibiila X 50. c. Pes II

X 33. d. Pes II Re III; glandular pore X 57- e. Pes III sin. X 29- f. Second

basipodite of pes IV. g. Pes V in ant. view X 33-

COPEPODA

153

The Jirsf pair of legs has the inner margin of the third basipodite less produced than in the
preceding species; the Se of Re I is rather short, but strong, and the Se of Re II, which is fairl}' strong,
extends only a little beyond the middle of Re III; the other natatory legs are scarcely different.

The Jifth pair of legs is in main features like that of Ch. notacantha, but differs in several de-
tails. The right endopodite (text-fig. 43 c) has a more regular shape, and has a somewhat different shape
terminally; the third segment of the right exopodite (text-fig.. 43 c) has, inwards, characteristic incisions
and processes. The left endopodite has a more regular shape, and is terminally produced into a short
tooth (text-fig. 43 d). The second segment of the exopodite is of more equal breadth throughout, and
the third segment is distinctly more slender (text-fig. 43 e) ; the arrangement of the series of hairs on
the posterior surface of Re III shows characteristic features of specific value (fig. 8 a PI. V).

Text-fig. 43. Chirudina parvispina Farr.

a. f cf. Abdomen X 22. b. Head X 22. c. Pes V dext. Ri + Re X c. 50. d. Pes V Ri sin. X 66. e. Pes V sin. Re II— III

X 75- f. yc? (Stage IV). Head X 66- g- Abdomen X 66. h. Pes V X c. 80.

Occurrence. The S/S Thor has gathered this species at two stations viz:

"/^ 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire i fc?, 2 yc? (V), 2 y? (V), i y? (IV), i yc? (IV).
'0/7 1904 St. 180 6i°34 L. N. i9°03 L. W. Yt. 1800 M. Wire i yc? (V).

This species has only been recorded by Far ran from the west coast of Ireland between 580
and 680 fathoms at 54°53 L. N. io°42 L. W. in the mouth of November 1904, and at 54°57 L. N. io°5i
L. W. in the month of February 1905.

Remarks. The specimen (young male) described by Far ran is scarcely different from my
specimens. The female is perhaps identical with Ufid. spedabilis G. O. Sars (1900, p. 59), which is, how-
ever, much bigger (f? 8 mm.), but in other respects, except by the shorter Se of Re I pes I, is scarcely
different in any features of importance. If, however, Sars' male (6 mm. long) and female really belong

20

'Ihe Ingolf-Expcdition. IJI. 4,

JC4. COPEPODA

to the same species (they were gathered in the same sample at 84° L. N., "the tow-net having been
lowered to 130 metres"), Ch. parvispina and spcctabilis are scarcely identical, as Sars' male possessed
a rounded lateral corner and a distinctly more elongate third segment in the exopodite of the fifth foot.

Valdlviella vStener.

18S3? Euchrete pars Brady.

1904, Valdiviella n. gen. Steuer.

1905. — Steuer. G. O. Sars.

1908. Valdiviella Steuer. Farran.

1909. — — A. Scott
191 1. — — Wolfenden.

According to G. O. Sars and Wolfenden this genus is nearly related to Ejic/icrfc; the
structure of the maxillulae and the maxillae bear out this opinion. With some right Steuer suggests
that it ought to be referred to the AcHdeidae; the structure of the legs, of the labrum, the labiimi and
the antennulae support this view. On account of the two egg-balls and the distinctly three-segmented basi-
podite of the maxillulae, I think that the form is a rather primitive one. V. oligartlira Steuer, insignis
Farran and brevicornis G. O. Sars, as well as the curious V. mitior Wolf, are certainly good species
A. Scott has referred a young male, probably belonging to this genus, to Brady's Euc. gtgas; he is
certainly wrong; his specimens are from the Malayan Seas and Brady's from the west coast of South-
America; the length of the former was 8 mm. and of the latter 5-25 mm. The lateral corner of Brady's
specimens had a long lateral spine, that of Scott's species a short triangular one.

45. Valdiviella insignis Farran.
(PI. VI figs 2 a— e; text-figs 44 a — d).

1908. Valdiviella insignis n. sp. Farrau, pp. 45— 46, pi. Ill figs 1911. Valdiviella insignis Farran. Wolfenden, pp. 247 — 248,

1—6, pi. IV fig. 5. I Taf. XXXX figs 6-7.

Description. f$. Size of specimen from St. 183 was 1175 mm.; anterior division 8-5 mm.; urosome
3-35 mm. Farran's specimens measured 11-5 — 12'0 mm.

The anterior division, which has distinctly rounded lateral corners without tuft of hairs, is
rather clumsy; the rostrum consists of two short, well separated spines; the first thoracic somite is com-
pletely fused with the head, and the fourth with the fifth. The anterior division is 2-5 as long as the
abdomen, which has the proportional length as 45, 35, 25, 11, 11. The genital somite is almost sym-
metrical and only slightly produced below; the vulva is seen laterally as an incision between an
anterior and posterior process. The somites III — IV have ventrally a tuft of long hairs; the posterior
margins, not only of the III— IV tergites but also of the I oj H, are denticulated. The furcal rami and
the setae are scarcely different from Farran's description; the appendicular seta seems to be longer
than figured by Wolfenden.

The antennulae^ which extend a little beyond the end of the thorax, have not the obtuse angle
between the proximal and distal portion, which is found in Ettchcefe^ the segments 80^9 and 24'>5 25
are almost completely fused. The ringed terminal setae are less powerful than those found in Euch(Ete\
no proximal setae were found in segments 10, 11 and 20 — 23; rather short triangularly pointed ".i55sthe-
tasken" were observed in segments 5, 9, 12, 14 and 19. The measurements are even in minor details

COPEPODA jcc

like Farran's description and very characteristic; the segments Scvig are 1-3 as long as segment 7, and
again 1-2 as long as 13; the segment 17, which is three times as long as the segment 14, is a little
longer than the segment 19, and 1-4 as long as 24^25. The basipodite III of the «;/A;///«r has a single
well developed seta; the Ri I has 2 fairly long setae, and the Li of Ri II has at least 7 longer and
shorter setae. The exopodite is a Httle longer than the endopodite; its first segment is well developed
without any seta, and the second has a short terminal seta. The mandibjilae have the teeth developed
in a curious way, as shown in Farran's fig. 3; the basipodite III possesses proximally a fairly long
somewhat curved seta and, medially, a short one; the Ri I has at least one seta, and the Ri II 8
powerful long setae, and more medially, a fairly long slender one. The maxUlulae have in general
shape some similarity to Euchmtc; in the Le were found only 6 well developed setae, of which the
third is the longest in several specimens, and not 7 as figured by Farran (fig. 5), as the proximal
was probably wanting; the Li I has only 11 setae, as S 12—14 on the posterior surface are missing;
corresponding to Li II— III only a single lobe with 4 setae was found. The Basp. Ill has i seta, the
Ri I 2 and the Ri II '>i III 3 strong setae. Three basal segments are easily recognized in this species;
the Basp. I is adorned with Li I, the Basp. II with Li II and Le I, and the Basp. Ill, which is well
articulated, has the two branches. The maxillae are like Farran's fig. 4 PI. Ill; the first basipodite
has the exterior margin distinctly concave in the middle; the Lob. I — IV have posteriorly a distinct
spinous area. The proportional length of the segments in the niaxillipeds is 60, 90, 26; they are scarcely
different from those of V. oligarthra.

The pes I has the Ri I — II completely fused, and the Re I is only indicated by a medial incision
and a powerful Se; as shown in fig. 2 a, a glandular canal and pore was present in the exterior margin
of the second and third division; the pore in the former was covered by a spine-shaped mass, and
both pores were surrounded by numerous hairs. The^^j //has the distinction between Re I — II indicated
by a medial incision and a well developed lateral spine; the articular membrane is anteriorly repre-
sented by a faint line, which is not seen posteriorly. The unsegmented Ri has near the tip on the
anterior surface a minute pore (text-fig. 44 b). Near the base of Se Re II and Se 3 Re III but not
in Re I, wide glandular pores are found, in connection with big sacs with glandular cells, which are
placed proximally to the articular membranes between the Re I— II and Re II — III respectively. The
/e'j /// differs from pes II by the distinct articular line between Ri II — III; a distinct glandular pore
is found at the base of Se Re I; the pes IV is in main features like pes III, but the Basp. II has
comparatively few hairs along the inner margin.

The epistoma is represented by a short protuberance, which is placed somewhat behind the
insertion of the antennulae; it is steep in front, and smoothly sloping behind, and apjDcars quite smooth.
The labriim is rather prominent; on the anterior surface, somewhat in front of the free margin, a trans-
verse row of fairly long stiff hairs (fig. 2 b) is observed; and more laterally, partly covered by this,
an oblique row; and along the hinder margin the usual row of numerous somewhat curled hairs (fig. 2 e).

The oral surface of the labruin (fig. 2 c) has the group i placed laterally, and consisting of
numerous short setae or granules; the group 2, which is well separated from this, and consists of
comparatively few longer setae, is closely followed by groups 3—4; the group 5 consists of more
numerous and comparatively longer setae.

156

COPEPODA

The lamina labialis does not show any features of interest (fig. 2 d); the area in front of it is most
like that of Chiridiiis\ it consists of a lateral, somewhat convex, row of fairly long setae and two median,
well separated, groups, as shown in fig. Behind the lamina and between the labial lobes, which were
not studied in detail, no setae were observed.

Y(i" (St. V). Size of specimen from St. 183 was 9 mm.; anterior division 6-5 mm.; urosome 2*5 mm.
The shape of the body is in main respects like that of the females, but the lateral corner of
the thorax has a small tooth ; of the four abdominal somites the second is longer than the third, which
is as long as the first. The measurements of the antennulae are somewhat different; the segments
17 and 19, which are of equal length, are 1-24 as long as 24'>^25, and 2-5 as long as segment 14. The
other appendages do not seem to show differences of any importance; the Re of the maxillulae pos-
sess, as usual in this stage, only 10 setae. The pes V of the male is somewhat like that of Euch<etc\
the Ri, which is almost twice as long on the right side as on the left side, is distally rounded without

any spines; the Re, which are of almost
equal length, are continued into a rather
strong spine (St), and have on each side
one or two Se, as well as 2 or 3 Si. The
structure of the pes V is distinctly diffe-
rent from Scott's fig. 26 of the corres-
ponding pair of legs in V. gigas, as well as
from Brady's fig. 5 of Etichate gigas.
Y (St. III). Specimen from Thor
St. 183: 5-58 mm.; anterior division 4-5;
urosome i-o8.

The rostrum and the frontal parts

are like those of the adult females; the

lateral corners are neither produced nor pointed; the first as well as the fifth thoracic tergites are well

marked out. The abdomen consists of two somites, of which the terminal one is almost twice as long

as the basal one.

The antennulae extend almost to the end of the abdomen; the ".i5isthetasken" are as in the
adults, but the Spr. was only observed in segment 19. The measurements are distinctly different, as
the distal segments are comparatively longer; the segment 19 is 1-3 as long as 17, and scarcely i-i as
long as 24'>3 25, which is 1-2 as long as 17. The mouth appendages, except the maxilltilae, are practically
like those of the adult; the Le had in the single specimen examined a single proximal long seta and
3 very delicate hairs distally; the Li I has only 10 setae, and the Re as usually 8.

The pes I differs distinctly from that of the adult by the more slender form especially of Ri;
both branches are undivided; the 3 Se are well developed, and a glandular pore is found in the third
division. The pes II has both branches unsegmented; the Re I — III has 6 Si and 4 Se; only at the
base of Se 3 Re III is a glandular pore found. The/rj IV \s comparatively more slender than pes II;
the Re I <Ni III have 3 Si and 3 Se, and a single glandular pore; the Ri I -^ III have 6 setae altogether.
In lateral view the labrum and labial appendages are scarcely different from those of the adult.

Text-fig. 44. Valdiviella hisigms Farr
a. f 9. Abdomen X 8. b. f 9. Pes III Ri III in anterior view with gland X 59-
c. Yo' (St. V). Left lateral comer X i6- d. Y d ^St. V). Pes V in ant. view X 18.

COPEPODA J rj

Occurrence etc. The S/S Thor has twice gathered a few specimens of this interesting species, viz:
"/? 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 3 f ? (one with 2, the others with single egg-
sac), 2 yd' (V), I y (III).
'% 1904 St. 180 6i°34 L. N. i9°o5 h. W. Yt. 1800 M. Wire 4 f ? (one with 2 egg-sacs), i yc? (V).

On the west coast of Ireland "three specimens of this species were taken at depths of 700, 730
and 1150 fathoms. By Wolfenden it has been recorded at about 20° L. S. and 20° I^. W. On account
of the longer antennulae and well developed Se Re I pes II I think with Farran, in contrast to
Wolfenden, that this species is well distinguished from V. oligarthra Steuer from the South Atlantic.

Euchaetidae.

Euchaete Philippi 1843.

A. Scott has established a new genus (1911 p. 64) Pareuchate with E. norvegica as a type in
contrast to the true Euchmte with E. marina as type species; the latter is characterized by the fifth
pair of the legs in the male, which has the Re III of the left foot elongated and pointed, and in
the females ''two of the six apical spines on the first maxilliped, in addition to being furnished with
rows of very short spinules have also a number of moderately long and conspicuous spinules". The
latter characteristic is very interesting, but probably not important enough for the establishment of
a new genus, especially as a single apical seta of the mentioned structure was found in E. hebes, in
which pes V of the male is of the E. norvegica type; in E. acuta only a single seta of this structure
was found.

In spite of specific variations the structure of the epistoma, and the anterior and posterior surface
of the labrnm show, as seen by comparing the figures on PI. VI and the descriptions, common features;
the arrangement of the hairs in front of the lamina labialis is fairly characteristic.

The arrangement of the glandular pores in the legs does not show specific difference of great
value. In the outer margin of Re III pes I, somewhat beyond the middle, a glandular pore was found,
alike, but less distinctly developed than the corresponding pore in Valdiviella insigtiis Farr. (PI. VI fig.
2 a). In the second pair of legs a pore is found at the base of Se Re II and Se 3 Re III as well as
one minute one near the tip of Ri III; in the third and fourth pair, in addition to these, a pore is
found at the base of Se Re I.

In this genus the adult females show the most characteristic systematic features, especially
in the structure of the genital somite; it must be remembered, however, that the usual inspection of
the genital area from the side and from below is not quite satisfactory for a full estimation of the
characters. A full dissection is often necessary to understand the complicated structures of the vulva;
unfortunately, I have not had the opportunity of doing so at the present. The characters found in the
number of setae in the maxillulae, as well as in the relative length of the spines in the exopodite of
the second pair of legs are of value, but often show some variations. To refer the copepodites as well
as the adult males to the right species is often impossible.

158

COPEPODA

As a good deal of confusion exists as regards the determination of several species, I think the
following synoptic key of the adult females may be useful.

j_ One of the apical setae of the maxillae with numerous short spinules and

a few long ones. Lateral corner rounded.
2. The genital somite on the left side with a conical process. 4 mm. E. acuta.

2. The genital somite on the left side dorsally a hairy process. On the right

side of the vulva a laminous process. 3-5 mm. E. licbcs.

I. All the apical setae of the maxillae of the usual structure.

2. Si of the furca distinctly shorter and thinner than St. 2. Lateral corner rounded.

The posterior process of the vulva longer than the anterior. 10 mm. E. glacialis.

x. Si of the furca distinctly longer than St 2.

4. Lateral corner pointed.

5. Lateral corner triangularly pointed without tuft of hairs 6-6 nun. E. tonsa.
e. Lateral corner with a well defined pointed process; distinct tuft of hair.s. On

each side of vulva a median process. 8'8 mm. E. norvegica.

4. Lateral corner rounded.

6. 3 distinct processes on each side of the rather low genital protuberance.

56 mm. E. bisinuata.
6. Without 3 distinct processes on the same level.

7. Genital protuberance very deep, almost squarely truncate with a small median

process on each side of the vulva. 67 mm. E. gracilis.

7. Genital protuberance not very deep. On each side of the vulva in front of

the posterior edge a laminous process.
8. Dorsally and behind on the protuberance small process. Le maxillulae with

9 setae. Se Re I pes I long and slender. 8-9 mm. E. Hansenu.

8. No such process observed.

9. On the left side of the genital somite a conical process found

10. The Se 2 Re III pes II does not extend to end of segment 11 mm. E. Farraiti.

10. The Se 2 Re III pes II extends beyond end of segment 8 mm. E. barbata.
9. On the left side of the genital somite no conical process found. Se Re I

pes I small or wanting.

11. The genital protuberance is prominent with short anterior frange. 8'2 mm. E. Brady.
II. The genital protuberance not very prominent

12. Shape of body clumsy. 6 mm. /:. Scotti.

12. Shape of body rather slender. 9-5 mm. E. Sarsi,

46. Euchaete norvegica Boeck.

(PI. VI figs 3 a— f; text-figs 45 a— s.)

1S64? Euchaete pestandreae Philippi. Boeck, p. 12.

1872. — norvegica n. sp. Boeck, p. 40.

1873. — carinata n. sp. Mobius, p. 271, tab. VII.

1885 pars. Euchaete norvegica Boeck. G. O. Sars, p. 234, t. 19.
1892. — — — Giesbrecht, p. 246, taf.

15, 16 and 37.

COPEPODA

159

1898. —

1899. —
1900 pars. —
1902? —
1903. —

1903. —

1903. —

1904. Euchsete uorvegica Boeck. Wolfenden, p. 133.

1898 pars. Euchsete norvegica Boeck. Giesbrecht & Schmeil, p. 40.

— — AuriviUius, pp. 89—90.

— — Th Scott, pp. 24S -249.

— — G. O. Sars, p. 58. pi. XIV.

— — Mrazek, p. 515.

— — G. O. Sars, pp. 38 — 39, pi.
XIV— XVI.

— — Norman, p. 137.

— — Jensen, Johansen, Levin-

sen, p. 86, tabel II.

Description, f ?. Size: One of the largest specimens (Thor St. 183) anterior division (276 + 3-68);
posterior division 2-42; total length 8-86 mm. Sars' females measnred 8 mm. and Giesbrecht's 8-5.

1905-

1905-

1907.

1906 pars.

1908.

1908.

1911.

1913.

G. O. Sars, p. 5.

Farran, p. 35.

Damas & Koefoed, p. 396, 407.

Pearson, p. 16.

V. Bremen, p. 52— 53 %• 59-

Farran, p. 40.

Farran, pp. 95 — 96.

Stephensen, p. 320.

] a D o p

Text-fig. 45. Euchnte norvegica Boeck.
a. 19. Pes I in anterior view X 57- b. In posterior view X 57- c. fd". Lateral corner of the thorax from the left X 18.
d. From the right X 18. e. Pes V Ri sin. iu internal view, f— g. Y9 and yS (Stage V). Abdomen X 12. h. YcJ {St. V).
Furca X 18. i. Pes V X 28. j-k YQ-d" (St. IV). Abdomen X i6- 1- Vc? (St. IV). Pes V X 65. m. Y (St. III). Rostrum X 59.
n. Y (St. II). Rostrum X 59- o. Y (St. II). Animal in dorsal view X 18. p. Y (St. II). Abdomen in lateral view X 59- q- Y
(SL II). Maxillipes sin. in posterior view X 59- r. Y (St. II). Pes I sin. in post, view X 57- s. Y (St. II) Pes III sin. in post.

view X 57-

The last thoracic somite has laterally a minute tooth as figured by Sars; in one specimen it
was wanting on the right side. The genital somite has in front of the prominent ventral protuberance,
which possesses a small tooth on each side of the vulva, a characteristic small tubercle.

The /?nf/ pair of legs (text-figs 45 a — b) has the articular line between Re I and II rather com-
plete posteriorly; anteriorly it is wanting, except inwards, where a cliitinous line is observed, to which
a muscle is attached. The glandular pores are rather indistinct; in the /^'i- // they were only observed
at the base of Se Re II and Se 3 Re III and terminally in the middle of Ri; in the two following pairs
pores, even if indistinct, were observed besides at base of Se Re I.

l6o COPEPODA

Between the insertion of the antennae, (PI. VI figs 3 a— c.) an epistoma, directed forwards
and terminally covered with long, stiff bristles is found; between this and the well developed labrum,
which is gradually sloping anteriorly, a rather shallow portion is found; anteriorly the labnnii is
marked off by a chitinous transverse convex list, where the longitudinal muscles are fastened, which
move the marginal fringe of setae. The labrum bears in the middle two rather irregular rows of more
or less slender bristles. The marginal fringe consists in the middle on the well developed lobes of a
right and left group of fairly long hairs; more laterally a group of shorter hairs is found; orally an in-
distinct transverse row is found (cf. PI. VI fig. 3 a). The chitinous framework which supports the oral
surface of the labrum is in the main like, but less developed than, that of Euchirclla messhiensis (cf.
PI. IV fig. 2 a). In addition to the usual four central spots, 6 spots are present on each side. Just be-
hind the spots Nr. 4 a transverse group of short spines is found. The first lateral group of the longi-
tudinal series of delicate hairs is placed transversely, and fairly well separated from the more longitudinally
placed group 2; this again is well separated from the more or less fused groups 3 — 5, as seen in fig. 3 a.

The lamina labialis (fig. 3 b) is divided into a median and, on each side, two lateral serrations,
which are connected with a chitinous skeleton. The area in front has, as shown in fig. 3 b, a rather
complicated structure; on each side, in the middle, a granular area converging in front, is found, and
more laterally several slightly convex longitudinal series of delicate hairs as well as a square spinous area
just in front of the serrula 6-dentata; the latter is, as seen in fig. 3 b, placed on a well developed chitinous
system. Behind and between the branches of the lamina labialis about 5 oblique rows of delicate hairs
are found on each side. M 6 b i u s has given a fairly good description of the oral surface of the labrum
and the lamina labialis. The labial lobes (fig. 3 c), which are well developed and rather prominent, pos-
sess about 5 somewhat irregular longitudinal series of comparatively short hairs, which, posteriorly, are
fused into fairly big median groups. The region behind the area labialis proper does not possess any
group of delicate hairs, but somewhat medially to the articular cavities of the maxillae is found a
group of 15—20 long, stiff setae, directed inwards and almost attaining the middle; in the middle, more
posteriorly, a group of 10 shorter setae, directed forwards, is found.

f c^. Size: In one of the largest specimens (Thor St. 183) the total length was 6-34; anterior divi-
sion (2-53 + 1-95) 4-48; urosome i-86 mm. Sars' males measured 7 mm. and Giesbrecht's 5-45.

The lateral corner of the fifth thoracic somite (text-figs 45 c — d) is distinctly more produced on
the left side than on the right; dorsally, a small marginal tooth is found, more developed on the left
side. The first abdominal somite has the genital pore on the left side, and is somewhat produced on
the right side; on the same side laterally and dorsally near the base of the somite a triangular tooth
is found. The segments 12—13 of the aiifeniiulac are well separated on the left side, but have on
the right side the articular membrane indistinct, posteriorly. The measurements are practically like
those in the adult females. The Ri of the ai/fcmiac has on the interior lobe 5 plumous setae, even
longer than in the female, in addition to two short ones. The mandibulac -possess, m co\\ixa.s,t to Sars'
and Giesbrecht's description, a well developed, but .soft-skinned, manducatory part with 4 short mar-
ginal teeth (PI. VI fig. 3e). The viaxillulae are better developed than described by Sars and Gies-
brecht, though they are probably without value for mastigation. The Le has 5 strong setae; the
Li I possesses at least three delicate bristles, the Li 2 a single short one and the Li 3 a single

COPEPODA

l6l

somewhat longer; the Basp. 2 has 4, and the Ri at least 5 setae. The Re has 10 + i setae. The max-
illae are quite rudimentary soft-skinned, somewhat twisted organs possessing the usual number of
lobes, which bear soft appendages, on the distal lobes most like setae. The maxillipeds are less powerful
than those of the female, the L,i I of the basipodite i csi 2 has one hair, lyi 2 one short hair, Li 3 two
hairs and Li 4 a single hair in addition to a hooked organ surrounded by fine hairs like that of E.
bisinuata Farran (PI. VI fig. iic).

The second pair of legs differs distinctly from that of the female by the short Se Re II, which
only reaches the end of the segment, far removed from the base of Se i Re III.

The Re II— III sin. of th.& Ji/lh pair of legs (PI. VI fig. 3d) are in the main like Giesbrecht's
fig. 24 (Taf. 16), differing from Sars' by two not one, rows of serrations, between which the seg-
ment is distinctly more hollowed than in the two following species. The left endopodite consists of
two segments (text-fig. 45 e).

The epistoma and labrum are in lateral outline seen to be distinctly lower than those of the
females; by further examination (PL VI fig- 3 e) it was found to be poorly developed, without labial
lamina and distinct labial lobes; the complicated system of hairs found in the females seems to be
completely wanting.

Yq (St. V). Size of specimen from Thor St. 183: the total length 5-57 mm.; anterior division
(2'46-|- 179) 4-25; urosome 1-42.

The shape of the anterior portion differs from that of the f ? by triangularly pointed lateral cor-
ners (text-figs 45 f — g). The abdominal somites show the usual differences; in constrast to the f$, the Si
of the furca is distinctly shorter than the St. 2 (text-fig. 45 h). The antennulae are comparatively shorter,
but the arrangement of the appendages is completely like that of the f$; the measurements are,
however, slightly different; the segments 24^25 are at least as long as the segment 19, not i-2 shorter,
as the segment 23 is i-i as long as, not i-i as short as, the segment 16. The Re of the maxillulae
possess only 10 setae. The Re I — II of the first pair of legs are completely fused without trace of
segmentation.

The male of this stage is easily distinguished from the female by the presence of a fairly well
developed two-branched fifth pair of legs (text-figs 45 g and i).

Y^(St. IV). Size of a big specimen from St. 183 was 3-6 mm.; anterior divisiou (17 -|- i-o) =
27 ; urosome 0-90 mm.

This stage differs from the preceding one by the urosome, which consists of three somites only
(text-figs 45J— k), of which the last is the longest, the first the shortest; the subapical seta is, as in
the preceding stage, shorter than St. 2. The antennulae have the appendages like the adult females, and
the measurements show corresponding differences; the segments 24cn3 25, f. inst., are distinctly i-2 as long
as the segment 19. The Re of the maxillulae possess only 9 setae, as usual in this stage. The exopodite
of the first pair of legs is alone unsegmented, as not only Re I— II are fused but also Re II— III. The
Re II— III of pes II— III are fused with 3 Se, of which Se i Re II csi III pes II is comparatively long,
probably corresponding to Se Re II. The Ri II— III are fused in pes III— IV.

The Ingolf-Expedition. III. 4-

1 52 COPEPODA

The male of this stage differs from the female by the fairly well developed fifth pair of legs
(text-fig. 45 1).

St. III. Size of specimen from Ingolf SL 19 was 2-65 mm. long; anterior division (1-26 -|- 0-63)
= 1-89; urosome 076 mm.

The rostrnm is less prominent (text-fig. 45 m), and the lateral corners are regnlarly ronnded;
the abdomen consists of two somites only; the snbapical seta is, as in f$, mnch longer than St. 2. The
antennulae extend almost to the end of the furca; the usual long setae, which are more powerful in the
segment 7, are found, but the number of the short setae is much smaller, as the fused segments (4^5)
(2<^3) have only a single seta, as the segment 6 — 10 do not posses an)-, and as Spr. is only found in
segment 19. No "^5isthetasken" were found in segment 12, but, as usual, in segments 5, 9, 14 and 18. The
measurements are distinctly different as the segments 19 — 24 are comparatively longer than in the pre-
ceding stages; the segments 24<Ni25 are 1-3 as long as segment 19. The mouth appendages are in the
main like those of the adult females, but the number of the setae is as a whole a little .smaller, f. inst,
the Re of the maxillulae has only 8 setae. The two first pairs of legs are scarcely different from stage
IV; the pes III has in Re II "^ III only 2 Se and 4 Si, and the Ri is undivided; the pes IV has Re I— III
fused with a basal Se well separated from two distal ones.

St. II. Size of specimen from Ingolf St. 19 was 179 mm. long; anterior division (0-92 + 0-41)
= 1-33; urosome 046.

The lateral corner of the anterior division is not regularly rounded, and the rudimentary fourth
pair of legs is found as a wing-like expansion (text-figs 45 n — p). The subapical seta (Si) is thicker and
longer than the St. The antennulae, which almost extend to the end of the urosome, have several of
the proximal segments (1 — 18) more or less fused. A long distal seta is found in segments 3'nj4, 6c:^7,
14 and 18. No "iEsthetasken" were found. Beyond the segment 18 the segments become suddenly longer;
the 19 is almost twice as long as the 18; the segments 19 — 23 are of almost equal length; the seg-
ments 7,\'Si 25 are 13 as long as 19. The mouth appendages show similar differences as in the preceding
stages; the maxillulae have onlj' 7 setae in Re; the maxillae are less powerfully developed, as seen in
fig. 3 f. The maxillipeds have only 2 setae in the middle of basipodite 3, as the median one is wanting.
The Ri possesses only 5 setae.

The pes J is comparatively more clumsy; 3 Se are present, as in the preceding stages. The
pes II has the Re I indicated with well developed Se; in addition, 2 Se and 4 Si were found. 'Y\iQ pes III
is like 'Ca.^ pes IV oi the preceding stage, with 3 Se and 3 Si (text-figs 45 r— s).

Occurrence. Davis Strait. The Danish Ingolf Expedition has in the southern part of the Davis
Strait as far north as 65° L. N. from ^s/e — "7? ^^95 taken 9 samples containing Euc/i. norvegica ; in the
following 5 a fairly big number was found. In the table (p. 163) a few stations south and south east
of Greenland are dealt with.

As the species was found neither in any surface sample nor more north than 65°, there is reason
to suppose that the form does uot belong to the fauna of the surface, but belongs to the northern
prolongation of the Atlantic fauna. Propagation has been found to take place at the mentioned season
in this region.

COPEPODA

—

163

iSgS-

Ingolf

L. N.

I..W.

Depth in
fathoms
and net.

Temp, at
surface.

VI

V

IV

III

II

I

Number of
specimens
examined.

Cf

9

d

9

d

9

V7

SL28

65°i7

55°42

V.I 100— 0

1-15° C.

1
10

10

16

I

—

St. 27

64°54

55°ro

V.' 200—0

3-9° C.

4

4

7

2

3

I

=5/6

St. 25

63°3o

54°25

V.I 200—0

2-9° C.

20/0

24°/o

5°/o

7>

i4°/o

i5°/o

3o°/o

3%

115

=5/6

St. 24

63°o6

56°oo

V.I 200—0

4-2° C.

7°/o

34°/o^

200/0

30°/o

50/0

3°/o

I °/d

163

28/^

St. 36

6i°5o

56°2i

Trawl.

^

I

•■

—

—

.

V.I 100— 0

8-5° C.

34°/o

31%

i5°/o

i5°/o

5°/o

120

3°/7

St. 38

59° 1 2

5i°o5

V.' 100— 0

10° C.

II

8

5

2

6

-/6

St. 22

58°io

4S°25

V.I 200—0

5-35° C.

4

3

3

I

I

=°/6

St. 20

58°2o

4o°48

V.I 200 — 0

61° C.

6

10

18

6

6 .

19

I

•8/6

St. 19

6o°29

34° H

V.I 300—0

9° C.

8°/o

20 0/0

33°/o

20 0/0

90/0

9%

I 0/0

151

■7/6

St. 18

6i°44

30°29

V.I 200 — 0

10° C.

5°/o

240/0

220/0

260/0

9%

9°/o

SO/o

163

' Mean

s that sper

matophoies

were found att

chcd to the gt

nital somite of tliL

females or to pes

V of the males.

2

"••gg-

sacs

—

—

—

Denmark Strait. The Ingolf Expedition ha.s in Denmark Strait {^"'^^/e 96) taken 5 samples con-
taining E. norv.^ but only few specimens (stage V most numerous; a single i$ was found); in 1895 a
single sample (St. 11) with a fairly big number of specimens was found. The S/S Thor has at four
stations from '8-20^^ j^q^ taken numerous specimens with the young-fish trawl, among which were several
adult males with spermatophores attached to the fifth pair of legs, as well as females with eggs and
spermatophores. The table shows the relation between the different stages.

Ingolf 21/5 95
Thor 1% 04
18/6 04
I9l6 04
=0/6 04
=1/6 04

St. II
St 150
St. 152

St. 153
St. 154

L. N.

L.W.

64°34

65°5o

65°oo

65°27

65027

3I°I2

26°53
28°io

27°I2
27°IO

Depth and
net.

V.I 200—0 fm.
Yt. 400 M.Wire
Yt. Soo M.Wire
Yt. 1000 M.Wire
Yt. 800 M.Wire
Yt. 800 M.Wire

Temp,
at sur-
face

8-2° C.

VI

200/0
I
15

I

24

V

d"

33

i6°/o

27 0/0

I

5

7-5 °fo

I

4°/o

27
15

7°/o

5°/o

IV

<s

5
II

22-50/0

2

25

360/0

6

3
27 0/0

5
25

270/0

III

II

I 0/0

Number of

specimens

examined.

365

South of Iceland. South-west of Iceland the Ingolf has taken a few, mostly young, specimens in
5 samples; a single sample from the deep sea contained an adult female with spermatophore, in the
others from surface-hauls copepodites of stages V— IV, were found, but no adult.

In the Atlantic, south of Iceland, the Ingolf Expedition has (J-^/e 96 and 9/3 95) taken 4 surface
samples with a few young specimens of stages IV— V; and in addition to these 7 samples from lower
layers, of which 5 contained adult specimens. The S/S Thor has in this region taken 11 samples (^Vs
1904, V7— ''*/7 1903—04 and Vg 1904), which all contained adult specimens.

164

COPEPODA

Ingolf 3/6 96

3/6 96
"/6 96
9/8 95

'Vs 96
Thor 9/7 04

.0/7 04

'/9 04
"/y 04
24/s 04

St. 68
St. 69
St. 63
St. 40
St. 49
St. 47
St. 178
St. iSo

St. 285
St. 183
St. 104

L. N.

62°o6
62°4o
62°4o
62°oo
62°o7
6i°42
63° 1 1
6i°34

62°49
61-30

62°47

L.W.

2 2 "30

22°17

i9°o5
2i°36
i5°o8
I3°i4

2I°30

19=03

iS°46
i7°o8
i5°03

net

V.' 100— o fin.

V.' 100 — o fm.

V.' 100 — o fm.

V.' 100— o fm.

V.' 100— o fm.

V.I 100— o fm.
Yt. 78oM.Wire
Yt. 400 M.Wire
Yt. iSoo M.Wire
Yt. 500 M.Wire
Yt. 1800 M.Wire
Yt. 1500 M.Wire

Temp,
at sur-
face.

8-8° C.
7-3° C.
8-3° C.

13-5° C.

9-3° C.
ro-6° C.

VI

I°/o

4

6°/o

I

l°/o

I

loo/o

51 "/o

9

4°/o
25'

2I>

33°/o

20'

I

35°io

1*2
19 0/0

I'2

39%

15

120/0
22%

5

I

2

200/0

22

I
210/0
32°/o
i-5°/c

36

75°/o

63%

4

20

8

23%

ID

1 1 0/0
240/0

1-5%

IV

2
5°/o
60/0

2
I

120/0
16

ly/o
80/0
20/0

I
3°/o
4>

60/0
12

15 °/o

7°/o
5%

III

II

Number of

specimens

examined.

100
174

163

170

1235
217

The presence of adult males and the presence of females with spermatophores and egg-sacs
certainly indicate that propagation takes place or has taken place; at St. 183, where among 230 f$ 60
had spermatophores and had 3 egg-balls, but especially at St. 104, where 30 of no fc^ had sperma-
tophores attached to the fifth pair of legs, and 50 of 85 f ? wore spermatophores and 15 wore egg-balls, a
great number of specimens certainly are active in propagating the species.

Iceland-Fseroe Channel. The Ingolf Expedition has not found any adult specimens in two
samples taken near the surface from the Iceland-Fseroe channel, but in those (four) from the deeper

L.N.

L.W.

St 52

63°57

i3°32

St 57

63°37

I3°02

-

6i°32

io°47

St 45

6i°3i

9°43

St. 102

6l°4I

i3°3i

St 163

62°36

I2°05

St. 99

6i°i5

9°35

St. 63

64°o5

9°38

St 78

6i°o8

9°20

St 70

63°33

6°20

St 124

6i°o4

4°33

Depth and net

Temp, at
surface.

VI

IV

III

II

Number of
specimens
examined.

Ingolf 15/5 96
20/596
"/s 96
"/5 96

Thor 23/5 04
28/8 05
^^504

s/.i 04
'V504

9/.104
33/7 05

V.I 200 — ofm.

V. 100 — o fm.
Cyl. 14

V.2 100 — o fm.
Yt 15 M. Wire
Yt 300 M. Wire

Trawl. 900 M.
Yt. 1000 M. Wire
Yt 1700 M. Wire

Yt 1 00 M. Wire
Yt 1000 M. Wire

8-3° C.
8-2° C.

91° C.

9%

I
28

I

120/0
9

1

5
15

4
4

I

120/0
I
2

24

1-2

22

55 °/o

1-2

37

1-2

36

I

13

960/0
2
II

I

1

I
5°/o

3
19

I
20/0

I

6

1-5 °lo

7
35
II

460/0

17
6

1 1 0/0
7

2°-5°/o
2

3
3
7

80/0

3
4

5°/o

I

II

14
6

6°/o
6
2

120/0
8

I

Iio/o

3°/c

3%

156

COPEPODA

165

layers had always found adult females. The S/S Thor has taken samples at 15 stations; adult specimens
were found at all except two. Adult males have been found from the month of May till August.

North of Iceland. North and north-east of Iceland the Ingolf Expedition has at 4 stations
taken a few young specimens, and at one adult females. The S/S Thor has at a single station
taken a fairly large number of adult specimens.

Ingolf Vs 96 St. 128 66°5o L. N. 2o°02 L. W. Trawl. i ^ (V), i ? (V).

'% 96 St. 102 66°23 L. N. io°26 L. W. V.^ 100— o fm. Temp, at surface 0-3° C. 2 f ?, i (III).

^3/^96 St. ii7 69°i3L.N. 8°i3L.W. V.^ loo-ofm. — 4-1° C. i (III), 2 (II).

2i/7 96i2.3oa. m. St. ii8 68°27L. N. 8°20 L. W. Closing net 1030 fm. — i ? (V), i ? (IV).

Thor "/^ 04 St. 214 67°i9 L. N. i7°55 L. W. Yt. 800 M. Wire 11 f c?, 35 $ (eggs

sperm.), 2 ? (V), 2 c? (IV).
South of the Faeroes. The S/S Thor has in the Atlantic, south-west of the Faeroes, at six
stations taken adult males and females; in the samples enumerated below the number of specimens
was fairly big; at 5 of 6 stations south-east of the Fseroes adult females were found.

1905

Thor.

L.N.

L.W.

Depth and net.

VI

V

IV

III

II

I

Number of
specimens
examined.

d-

9

cf

9 •

■<^

9

3V8

-/6

St. 167

St. 72
St. 88
St. 90

St. 172
St. 173

57°46

57°52
48°09

47°33

57°33
57°52

9°55W.

9°53W.
8°3oW.
7°4oW.

4°26 E.
8°oi E.

Yt. 300 M. Wire
Yt. 1500 M. Wire
Yt. 1500 M. Wire
Yt. 300 M. Wire
Yt. 300 M. Wire
Yt. 500 M. Wire
Yt. 300 M. Wire
Yt. ScK) and 300 M. Wire

I

12
43°'o

I

38
10

35

1

3

10

1-2
46

1-2

32 Wo

I

36

I

18

I

1-2
30

7

3

14

8%

20

5

5

I

3

7

11%

9

4

7
8

5
2-5 %

I

5
I ,

2

5

2-5%

I
5

1%
4

3"

East-Greenland Expedit. That scarcely any specimens were taken in the numerous surface
hauls during the crossing of the Danish East-Greenland Expedition 1900 (June— September), in the
Norwegian Sea, in the ocean east of Greenland, in Denmark Strait and the Atlantic south of Iceland,
seems to indicate that the species is extremely scarce at the surface.

In vertical samples from near the coast of Greenland a few specimens were found. As so few
specimens have been taken, I think a full account of the stations may be useful.

25/6 1900 Jan Mayen. Closing net 60 -50 fathoms i y (III).

V7 3 P- !"• 7?)°?)'^ N- 2>"2P W. Vertical. 300—0 m. i f $.

8/7 2 p. m. 74°28 N. i5°36 W. — 400-0 m. i f c?, 5 f ?, i c? (V), i ? (V).

•% 6 a. m. 74°28 N. i5°36 W. — 100— o m. i c? (V), i ? (V).

— — — — Closing net no— 40 fath. i c? (IV).

j66 copepoda

3/9 12 p. m. 68°22 N. if IS W. F. 300 I ? (V).

■8/9 12 p. m. Kap Dan F. 347 i cT (V).

^4/9 10 p. m. 6i°o6 N. i6°26 W. F. 391 i J" (V); i c? (IV).

12 p. 111. F. 392 I ? (IV).

Distribution. Eucho'te norvegica is recorded from the Atlantic at least as far south as 51° L,. N.
from the west coast of Greenland at little Karajak-Fjord (Vanhoffen), and north of Iceland (Paul-
sen). It has been found abundantly in the Fceroe channels, and in the Norwegian Sea, but onl)' in the
northern part of the North Sea. It is, according to Sars, frequent in deeper layers along the whole
coast of Norway, and so it is in the Skager Rak. It is recorded as common in the Barents Sea. The most
common species of Euchwfe found in the Polar basin crossed by Nan sen was E. glacialis^ not nor-
vegica as originally proposed by Sars, but the latter sjDecies was nevertheless (Sars 1903 p. 39) found
occasionally in two different places. As Mrazek says that his specimens attain a length of about
10 mm., he has probably confounded the two species.

Etichfete norvegica has been taken by the Due d'Orleans (from 7/^ — i/g 1905) at most stations
between c. 10° Long. East and the east coast of Greenland as far north as 80° I^at. North, but was never
common. The species was never common between c. 300 — 100 meters, where adult females with ovi-
sacs or spermatophores and males (sometimes with spermatophores attached to pes V) were often found;
between o — 100 met. mature specimens were never found, but now and then a few young ones (1907
p. 407). Wolfenden has found the same to be the case in the Atlantic and writes (p. 133) "Young
and undeveloped specimens are not uncommon near the surface, but the adult animal appears to prefer
the deep water down to 500—600 fathoms". My material, as far as it goes, tells the same story.

Though the species has a wide distribution in the northern seas, and though it is occasionally
found propagating here, I think we are right in regarding it as a species which belongs to the North
Atlantic, and by the Atlantic currents are carried to the polar regions; it seems in any case to be
distinctly more common in the Fseroe channels and the west of Iceland than in the ocean between
Norway, Greenland and Spitsbergen.

47. Euchaete tonsa Giesbrecht.
(PI. VI figs 4 a— b; text-figs 46 a— g).

1895. Euchsete tonsa n. sp. Giesbrecht, p. 251, pi. IV figs 9 — 10.
iSg8. — — Giesbr. Giesbrecht & Schmeil, p. 40.

1904. — — — Cleve, p. 190.

1905. — — _ G. O. Sars, p. 5.

1905. — — — Farran, p. 35.

1906. - — — Pearson, p. 17.

1906 Euchaete tonsa Giesbr. EsterK-, p. 64, pis 9 — 10.

190S. — — — V. Bremen, p. 55, fig. 62.

1908. — — — Farran, p. 40.

1909. — — — A. Scott, p. 72, pi. XIV figs 8—15.
191 1. — — — Wolfenden, p. 298, text-figs 50 a-d.

Description. % Size of specimen from St. 72 Thor 1905 was 6-4 nun.; head -|- first thoracic
tergite 2-8, four posterior thoracic somites i-8; urosome i-8 mm.

The lateral corner is like Wolfenden's figure, and more pointed than figured by Scott and
Esterly for Pacific species; the point is, as shown in text-figs 46a— b, more prominent on the left than
on the right side; no lateral tuft of hairs is found.

COPEPODA

167

The genital somite is, as seen in fig. 46 a, distinctly produced below, but the outline is not quite
like any of the published drawings. The structure of the vulva seems to be a good deal more com-
plicated than figured by Wolfenden. The subapical seta is more slender, but longer than St. 2.

The antennulae are like Scott's fig. 11; the segments 24<Ni25 are distinctly shorter than seg-
ment 19, and 23 than 16. The mouth-appendages are scarcely different from those of E. norvegica.

The pes I is in main features like E. v., but distinctly different from »Scott's fig. 13; the arti-
cular membrane between Re I — II is fairly developed anteriorly, but posteriorly is wanting, except
medially; the Se Re I is fairly developed. The pes //is like Wolfenden's fig. 50c, but in details
is different from Scott's figure; the Se Re II scarcely reaches the base of Se i Re III, and Se 2 al-
most reaches the base of short Se 3. On the posterior surface of the second basipodite iu the fourth
pair of legs a number of delicate hairs are found in the middle.

The epistoma and outer surface of the labrum are in the main like those oi Ench. glacialis {ci. p. 169)
and slightly different from E. iiorv. The oral surface of the
labriiin is like E. norv.^ except the two first groups of
hairs, which are placed as .shown in fig. 4 a. The area
in front of the lamina labialis is like that of E. norv.^
but inwards delicate spines are found instead of granules;
the most lateral group of hairs is almost as wide as long.
The lobtis labialis possesses in similarity with Euc. glacialis
a posterior lateral groujD of hairs.

c?. Size: 5-89 mm.; anterior division (2*56 4-i'6);
urosome 173.

Shape of the body is scarcely different from E.
norv. The rostrum is a little more obtuse and somewhat
shorter. The lateral corners are rounded and somewhat
less produced, but more produced on the left than on
the right side; the difference is, however, less marked

than in E. norv. (text-fig. 46 c). «■

_,, , , 1 1 1 ii J Text-fig. 46. Euchate tonsa Giesbr.

The antennulae reach somewhat beyond the end ^ ^^ ^^^^j^^, ^^^^5^^ ^ ^^ ^ ^^ ^^^^^^^ ^^^^^^

of the thorax and are scarcely different from those of from the right x 16 and x 52. c. f d". Lateral comer

from the right X 18. d. Pes V Ri sin. from the right
E. norv. (iu situ) X 59- e. Ycfl?) (St. V) with abnormal pes V

The pes I has a well developed articular mem- X 16. f. YcJ(?) (St. V). Abnormal pes V x 39- g- y<S

(St. V). Pes V in anterior view X 33-
brane between Re I— II, and the Se Re I is very short,

scarcely three times as long as wide. The pes II differs from ? by the slightly different shape of the
Se Re II— III, and by the Se 2, which does not reach the base of Se 3; the base of the process, pos-
sessing the Se 2 Re III, is, in E. norv., placed almost as near the end as the base, but is here placed
distinctly nearer the base than the tip.

The Ji/th pair of legs differs from that of Euc. norv. by the different shape and serration of
the process of Re II sin, which is distinctly longer, not shorter, than the ringed appendage (fig. 4 b),
and by the slightly different shape of the left endopodite (text-fig. 46 d).

j68 copepoda

Yq (St. V). Size of specimen from Thor St 82 1904 was 4-42 mm.; anterior division (2-07 + 1-23)
= 3-3; urosome i-i2 mm.

The body is somewhat more slender; the first abdominal somite is in some specimens rather
prominent ventrally; the lower surfaces of two last abdominal somites possess tufts of the fairly long hairs
sometimes represented in E. norv. The lateral corner of the thorax is less acutely pointed than in E. norv.
(text-fig. 46 e). The pes I has no articular membrane between Re I — II, and the Se I is extremely short;
the pes II is scarcely different from the adult females. The male only differs from the female by the
presence of a well developed fifth pair of legs; the Re sin. is rather obtusely truncate (text-fig. 46 g).

Yq (St. IV). Size of J* — ? from St 88 Thor 1905 was 334 mm.; anterior division (1-56 -|- 0-90)
= 2'46; urosome o-88 mm.; male from St 82 3-28 mm. and female 3-54 mm.

The body is more slender than in corresponding stage in E. norvegica^ and the lateral corners
are less distinctly pointed. The Se 2 of Re II ^ III in the pes II almost reaches the base of Se 3 in
contrast to E. norvegica. The pes V of the male is scarcely different from that of the other species.

Variation. A young male (St 82) (text-figs 46 e — f) had, as shown in fig., the fifth pair of legs
developed in a rather curious way; in another specimen the left lateral corner was evenly rounded,
but the right one pointed in the usual way.

Occurrence. The Thor Expedition has taken the species from the following stations in the
Atlantic south of Iceland (one west of Iceland), all in fairly deep layers.

"/7 1904 St 183 6i°30 L. N. i7°o8 L.W. Yt 1800 M. Wire i fc?, 4 f? (egg-balls + sperm.).

^Ve 1904 St 154 67°27 L. N. 27°io L.W. if?.

■5/6 1905 St 82 5i°oo Iv. N. ii°43 L.W. Yt 1200 M.Wire 11 f? (2 with sperm.), 2 ? (V), 6 ^ (V), 2 ?

(IV), 4 c? (IV).
31/8 1905 St 167 57°46 L.N. 9°55 L.W. Yt 1500 M. Wire i f? (sperm.), i ^ (IV).

8/6 1905 St 72 57°52 L.N. 9°53 L.W. Yt 1500 M.Wire 41?.

='°/6 1905 St 88 48°09 L. N. 8^30 L. W. Yt 300 M. Wire 2 f ?, i ? (V), i ^ (V), i ? (IV), i d* (IV).

Distribution. This species, or a nearly related, somewhat larger one, was recorded from the
Pacific by Giesbrecht and Esterly between 150 and 300 fathoms (1912, p. 321); it was gathered at
several stations in Malay waters by the Siboga Expedition. The Gauss Expedition has gathered the
species at two stations in the South Atlantic (c. 35° L. S. c. 10° L. W.), and at two stations in the Mid
Atlantic. Ou the west coast of Ireland it is, according to Far ran, "a rather characteristic species in
deep water tow-nettings ranging from 400 — 1000 fathoms".

Remarks. That the described female is identical with that mentioned by Farr an and Wol f e nden
is scarcely doubtful. Farran's specimens measured 4-95 — 5-25 mm., Wolfenden's specimens measured
5 — 5'3 nmi. The specimens from the Pacific are a good deal larger (Giesbrecht's 6-i, Esterly's 6-i and
Scott's 7 mm.), but as my adult females from the North-Atlantic measured up to 6-4 mm., the character
found in size is scarcely of great importance. The only character in which my specimens seem to
differ from Scott's etc. is the more pointed lateral corners and the structure of pes I —II, especially
the long Se 2 of Re III pes II. At present I do not deem the.se characters important enough to
establish two species.

COPEPODA 169

That the copepodites of the stages V — IV belong to the same species as the adult females is
especially borue out by the curious structure of the Re III pes II. That the described male, which as
realised from the above remarks is rather difficult to distinguish from E. norvcgica, is really the hitherto
undescribed male, is not quite certain; but, as K. tonsa also in other respects (e. g. structure of the labrum,
of the young specimens) shows greater similarity to E. norvcgica than to any other species, I prefer for
the present to refer the males and females to the same species.

48. Euchaete glacialis H. J. Hansen.
(PI. VI figs 5a-d; text-figs 47 a — n.)

1886. Euchsete glacialis n sp. H. J. Hansen, p. 74, pi. XXIII

figs 5—5 k, pi. XXIV figs I — I d.
1900 pars. — norvegica Boeck. G. O. Sars, p. 58, pi. XIV.
1902 pars. — _- _ Mrazek, p. 515.

1903. — glacialis Hansen. G. O. Sars, pp. 40 — 41, pi.

XXVII.

1904. Euchaete glacialis Hansen. Wolfenden, pp. 134 — 135, figs

I, 2, 7.

1905. — — — Th. Scott, pp. 222—223.

1907. — — — Damas & Koefoed, p. 408.

1908. — — — V. Bremen, p. 54 fig. 60.
1913. — — — Stephensen pp. 319 — 320.

Description. Size of specimen from Thor St. 154 1904 was 10-4 mm. ; anterior division (4 + 3'5)
= 7-5; urosome 29 mm. Sars' specimens measured 10 mm.

The lateral corner of the thorax is somewhat triangular, and possesses in most .specimens a
minute rounded process, which is not figured by Wolfenden and Sars (text-figs 47 a — c). The genital
protuberance is very prominent, and has on each side of the vulva, the ventral surface of which has
been figured by Wolfenden (p. 134), two distally rounded, lamelliform processes, of which the hindmost
is the longer. The subapical seta is distinctly shorter than the St. 2. The aiitennulae and niouth-liiiibs
do not differ from those of Eiic/i. norvcgica in any features of importance.

The articular line between Re I and II pes I (text-figs 47 d— e) is anteriorly wanting in the
middle, and that between Re II and III is only slightly developed, especially anteriorly. The Se i is
scarcely shorter than in E. ttorvcgica (cf. Wolfenden p. 134); the Se Re II is perhaps somewhat longer
than the corresponding Se in E. n.; but the difference is not so marked that any character can be
found in this feature.

The structure of the labrutn is in the main like that of E. norvegica; the arrangement of the
hairs on the oral surface differs in minor details; the lateral anterior group is placed transversely, and
consists of about 20 rather stiff, short hairs ; a sixth group, fairly well separated from the fifth, is found.
The lamina labialis and the serrula 6-dentata are scarcely different, but the hairs in front of the lamina
are distinctly different, as seen in fig. 5 a PI. VI, especially the lateral group, which consists of 3—4
longitudinal rows. The arrangement of the hairs on the labial lobes is somewhat different, as seen by
comparing figs 5 b and 3 c; especially the lateral basal group is better developed.

i^. Size of specimen from Thor St. 214 was 6-2i mm.; anterior division (2-65 + 1-95) = 4-6;
urosome i-6i mm. Hansen's specimens measured 77 and Sars' 8 mm.

The lateral corners (text-fig. 47 f) are, in contrast to those of E. norvegica, almost symmetrical
and only slightly produced, as on the right side in the species mentioned; the dorsal marginal tooth
is only indicated, or is very short. The first abdominal somite does not on the right side possess
any dorsal lateral process.

The Ingolf'Expedition. III. 4.

170

COPEPODA

The antenimlae extend about to the middle of the abdomen; the segments 12—13 are posteri-
orly fused, not only on the right but also on the left side, "^sthetasken" are found in all segments
except 23, even in the segment 20, in which they are wanting in E. 7torvegica. The measurements are
only in minor details different from those of the female. The interior lobe of the Ri of the antennae
has medially, in addition to the 5 + 2 setae, an extremely delicate one. The mandibulae and maxillae
scarcely differ from those of E. norvcgica. The maxillulae are, as seen in fig. 5 c PI. VI, better developed
than in other species; the Li i has, f. inst, 9 fairly long setae, and so has the Ri. The maxillipeds are
like those of E. norvegica, but the usual hooked process of lob. IV Basp. II seems to be represented
by a rather slender, straight, conical process.

Text-fig. 47. Eucliate glacialis H. J. Hansen,
a— c. f9. Left lateral comer in tliree specimens; most setae missing X 18. d— e. f9. Pes I dext. in anterior and posterior
view X 57- f- frf- Left lateral corner X iS. g. fcf. Pes V Ri sin. in internal view, h— i. Yc?— 9 (stage V). Abdomen X 16.
j. Yc? (st. V). Furca X 18. k. Yd" (st. V). Pes V X 33- 1— m. Ytf— 9 (st. IV). Abdomen X 16. n. Ycf (st. V). Pes V X Sg.

Pes I has the articulation between the Re I— II better developed than in the female, but the
Se of Re I is wanting; the pes II shows a similar sexual difference.

Pes V dext. has, about in the middle, an almost complete articular line between Re I and II;
proximally to this a short tooth is found exteriorly, which is indicated in E. norvegica; the Re III is
terminally somewhat hollowed, and less widened. The Re II — III pes V sin. are distinctly shorter; the
ringed appendage is comparatively short, and the serrated process is moderately hollowed between the
two rows of teeth ; the left endopodite has only one single segment (text-fig. 47 g).

Y5 (St. V). Size of specimen from Thor 1904 St. 154 was 771 mm.; anterior division (3-51 -j- 2'3)
= 5-81; urosome 1-9 mm. Hansen's specimen measured 7 mm.

This stage is easily distinguished from the corresponding stage of E. norvegica by the more
obtusely pointed lateral corner of the fifth thoracic somite (text-figs 47 h— j). The differences in the

COPEPODA 171

measurements of the terminal segments of the antennulae are like those of E. norvegica though less
marked ; the articular membrane between Re I — II of pes I is not completely lost

The fifth pair of legs in the male shows minute differences, as realised by comparing figures
(text-fig. 47 k).

Yo (St. IV). Size of specimen from Thor St. 154 was 5-02 mm.; anterior division (2'3 + i'43) ^ 373;
urosomn 1-29 mm.

This stage differs from the corresponding stage of E. norvegica by the more rounded lateral
corner of the thorax. The appendages show differences similar to those of E. 7iorvegica (text-figs 47 1 — n).

Occurrence. The Ingolf Expedition has taken the species at three stations only, viz:

2% 1896 St. 94 64°56 L. N. 36°i9 L. W. P. 100— o Temp, at surface 2-5° C. 4? (V), i yc? (V), i y d* (IV).
^5/^ 1896 St. 121 66°59 L. N. i3°ii L. W. V.' loo-o — 4-8° C. i f?, 4y? (V), 2 yd" (V) i y (HI).

27/^ 1896 St. 117 69=13 L. N. 8°23 L. W. V.2 loo-o - 4-1° C. i y (V).

The Danish East Greenland Expedition 1900 has taken it at three stations.

4/7 3 p. m. 73°32 L. N. 3=30 L. W. 300—0 meters i f? (with sperm.), i y? (V), i y? (IV).
8/7 2 p. m. 74°09 L. N. ii°3i L. W. 400-0 - i f?, 3 y? (V), i yS (V).
'% 6 p. m. 74°28 L. N. i5°36 L. W. 400-0 — i fc?, 2 y? (V), 3 yc? (V), i y? (IV), i y<? (IV).

The S/S Thor has taken the species at 8 stations.

2% 04 St. 153 65°20 Iv. N. 27°i2-5 L. W. Yt. 800 M. Wire i y? (V), 6 yc? (V).

"/e 04 St. 154 65°27 E. N. 27°io L. W. Yt. ? 16 f? (2 with sperm.), 2 y? (V), 2 yd* (V), 2 y?

(IV), 4yc? (IV).

Yt. 800 M. Wire 12 f?, 2 f c?, 4 >'? (V), 4 Yc? (V).

"/; 04 St. 210 66°43 L- N. i8°io L. W. Yt. 400 M. Wire i f?, 3 y? (V), i y? (IV).

"/; 04 St. 214 67°i9 L. N. i7°55 L. W. Yt. 800 M. Wire 19 f? (3 with egg-balls), 3 fc?, i yd" (V), i yc? (IV).

5/5 04 St. 63 64°o5 L.N. 9°38 L. W. Yt. 300 M.Wire 8 f ?, 6 y? (V), 6 yc? (V).

4/8 04 St. 230 63°ioL. N. 7°3i L.W. 2 f ?.

9/5 04 St. 70 63°33 L. N. 6°20 L. W. Yt. 100 M. Wire 27 f? (2 with sperm.), 5 f J", 5 7? (V), 3 Yc? (V),

3y? (IV), iy<? (IV).

^3/^05 St. 124 6i°04L. N. 4=^33 L.W. Yt. 1000 M. Wire if?.

Distribution. The species is very common in the Polar basin crossed by Nan sen, "from 300
metres to the very surface of the sea". By the Due d' Orleans it was taken at 15 stations in the sea
between Spitzbergen and Greenland between 79=56 L. N. 1=29 L. E. and 7i°22 L. N. i8°58 L.W. ("/7— 's/g
1905). Adult males and females partly with eggs and spermatophores were found at 5 stations between
200 and 500 metres; the young specimens were sometimes found in higher layers, but scarcely at the
surface ; in the lower layers between 500-1000 metres young ones only have been found. In the Norwegian
Sea it has, according to Sars, been taken a few times between 200-1000 metres. Damas & Koefoed
write (p. 408) without mentioning the source: "Dans la mer de Norvege: jamais a la surface; princip-
alement au dela de 600 metres". According to Wolfenden (1904, p. 133) "it is of rare occurrence in

j»2 COPEPODA

the pEEroe channel, and only once it occurred in the warm Atlantic area", and according to Da mas
& Koefoed "entre les Faeroer et I'lslande: pas an dessiis de 400 metres" (p. 408).

My own records show that the species was fairly common in the ocean north of Iceland, and
in Denmark Strait; it has been found a few times in the Iceland — Fseroe channel and a single
time south-east of the Faeroes. It is rather odd that it has not been taken in Davis Strait, but as
comparatively few deep sea samples have been examined from this region it is too early to exclude
the species from the fauna of this region. As it never occurred in any of the numerous samples brought
home by Thor and the Ingolf Exp. from the Atlantic south of Iceland, we are probably right in ex-
cluding it from the ordinary fauna of this region.

49. Euchaete Farrani n. sp.
(PI. VI fig. 6 a; text-figs 48 a— d.)

1883. nee. Euchaete barbata n. sp. Brady, p. 66, pi. 22 figs 1 1906. uec. Euchjete barbata Brady. Pearson, p. 17.

6—12. I 1907. — — — Damas & Koefoed, p. 409.

1892. nee. — — Brady. Giesbrecht, p. 246.

1894. nee. _ _ _ Th.Scott, p.5S,pl.VIfig. 17.

1898. nee. — — — Giesbrecht&Schmeil, p. 40.

1900. pars. — norvegica Boeek. G. O. Sars, p. 234, pi. 19.

1903. ~ barbata Brady. G.O.Sars, p. 41, pi. XXVIII.

1904. pars. — — — Wolfenden, p. 135.

1906.

nee.

1907.

1907.

nee.

1908.

pars

1909.

nee.

1909.

nee.

— — — G. O. Sars, p. 3.

— — — V. Bremen, pp. 54-55.
Pareuchsete barbata Brady. A. Seott, p. 70, pi. XVIII

figs 1—8.
— Sarsi Farran. A. Seott, pp. 75 — 76, pi.

XXI figs 9—15.

Description. f$. Size of specimen from Thor St. 230 was 1075 mm.; anterior division 8 mm.;
urosome 275 mm. Sars' specimens measured 12 mm.

The shape of the body is scarcely different from Sars' figure; the anterior division, which has
a rounded lateral corner with a tuft of long hairs, is 2-5 as long as the urosome. On the ventral surface
of the third to fifth abdominal somites tufts of powerful hairs are found. The comparative length be-
tween the 3 first somites is as 50, 30, 25.

The genital somite (text-figs 48 a— c), which is 1-2 as long as wide and i-i as long as deep, is al-
most as long as the following two combined; the ventral surface has a big protuberance for the vulva,
placed almost in the middle of the somite. In lateral view the ventral outline is anteriorly rounded,
in the middle almost straight, and posteriorly produced into a somewhat triangular process, which by
an incision is well separated from a "posterior process", which really is the posterior limitation of the
vulva; this posterior process is basally marked by an incision. Somewhat more posteriorly and dorsally
than the base of the genital protuberance on the left side a small rounded process is found; this
process has been found in all the examined specimens, and is best seen when the somite is examined
in not quite lateral view. In ventral view the vulva is seen to be limited by a slightly prominent edge
behind; laterally it is partly covered by a wing-like expansion, which is rounded in front, and pro-
duced behind. In the middle of the vulva a chitinous "plate" is found, which in the posterior margin
has a median incision, laterally is partly fused and covered by a somewhat trilobated process, and in
front is in the middle covered by a posteriorly triangularly pointed plate. The St. 2 of the furca is
almost twice as long as the St. 1—4, but much shorter than the distinctly geniculate Si.

The antc7irmlac, antennae, mandibulae, maxillae and maxillipeds do not show any feature of

COPEPODA

173

interest The I^e of the maxillulae show, however, some variation. In one specimen a single very
short hairy seta, a longer one and 5 very long ones were present on each side; in another specimen
I fairly long -f 5 very long were fonnd on the left side, bnt 2 short + 5 long on the right side; in 3
specimens 2 short -|- 5 long setae were fonnd on each side, and in one, on the left side, in addition to
the 5 long ones, one fairly long and one very short seta. The basipodite has 5 setae, the Ri I 3, Ri II
4 (one very delicate), and the Ri III 3 setae.

The pes I has the articular membrane between Re I — II fairly well developed anteriorly (text-
figs 48 b— c), and the Se Re I is fairly well developed. The Se Re II scarcely extends to the end of
the short Se i Re III, and the Se 2 Re III extends somewhat beyond the middle of the third division
(cf. Wolfenden's fig. 9, p. 134). The epistoma, anterior surface of the labrum, and the labial lobes

Text-fig. 48. EucliiEte Far rani n. sp.
a— b. f9. Abdomen in dorsal and lateral view X 18. c. fQ. Vulva from below X 180. d. f9. Pes I dext. in post, view X 57-

e. Pes I dext. in ant. view X 5°. f. YQ. Lateral corner X 18.

seem in main features to be like E. norvegica; the oral surface of the labrum is somewhat different
from E. norvegica, as seen by comparing figs 6 a and 3 a; the lateral anterior group has about 60 rather
strong short spines, the groups 1—6 are more regularly placed. The area in front of the lamina labi-
alis differs by the less square, more rounded, lateral group of short hairs.

Y$ (St. V). Size 8-3 mm.; anterior division 6 mm.; urosome 2-3 mm.

The lateral corners of the thorax are regularly rounded; in other respects, except the usual ones,
this stage is scarcely different from the adult females (text-fig. 48 f).

Occurrence. This species was gathered at the following stations by the Ingolf Expedition.
^/7 1896 St. 104 66^23 L. N. 7°25 L. W. P. 100— o fathoms Temp, at surf. 63° C. 5 f ?.
"/; 1896 St. 105 65°34 L. N. 7°3i L. W. - , 5-8° C. if?.

jy, COPEPOBA

24/y 1896 St. 117 69°i3 L. N. 8°23 L. W. V^ 100— o fathoms Temp, at surf. 4-1° C. i f?.

25/^1896 St. 118 68°27lv. N. 8°2oL.W. — 4'9° C. 2 f?(eggs + sperm.),

ly? (V).
^5/^ 1896 St. 120 67=29 L.N. ii°32 L.W. — 5-1° C. if?.

10/8 1896 St. 138 63°26 L. N. 7°56 L.W. i f? (eggs).

Deichmann has taken 2 f? (with egg-balls) 7o°32 L. N. 8°io L.W. Depth 470 fathoms.
The S/S Thor has taken a single specimen south of Iceland at a typical Atlantic station as
well as from a few stations in the Iceland— Fseroe channel.

"/? 04 St. 183 6i°3o L. N. i7°o8 L.W. Yt. 1800 M. Wire i f?.

■3/7 03 St. 164 62°io L. N. i9''36 L.W. Trawl. i f?.

23/7 05 St. 124 6i°o4 L. N. 4°33 L.W. Yt. 1000 M.Wire i f?.

9/5 04 St. 71 63°o6 L. N. 6°20 L.W. Yt 1500 M. Wire 7 f? (i egg-ball), i y?.

4/8 04 St. 230 63°io L. N. 7°3i L.W. Trawl. 1090 M. D. 27 f? (2 with sperm., 4 with egg-balls).

Distribution. This species, according to Sars, has been taken several times in the Norwegian Sea
"by the aid of trawl" "and always in great depth down to 2000 fathoms". By the Ducd'Orleans it was
taken "j-j 1200 — 1800 metres 79=34 L. N. 2=40 L. E., and ^^jy 800—1350 metres 78=05 L. N. 5=21 L. W.
The species seems most often to have been taken with the trawl ; the few observations indicate that
the species belongs to the northern deep sea plankton, with its main distribution in the seas lying
between Iceland, Norway, Greenland and Spitsbergen, but it is sometimes found south of Iceland.
Curiously enough it has not yet been found either in Denmark nor in Davis Strait

Remarks. Though the lateral tubercle of the left side of the genital somite is distinctly shown
neither in Sars' nor in Wolfenden's figures, I do not doubt that the described species is identical with
that described by the two authors. On account of the structure of the pes II, Far ran regards Wolf-
enden's species as identical with his E. Sars/; the size 10 — 11 mm. and the structure of the vulva
(fig. 5) make it necessary to refer at least some of the specimens to E. Farrani.

50. Euchaete barbata Brady.
(PI. VI figs 8 a— b; text-figs 49 a— p.)

1883.? Euchaete barbata n. sp. Brad}', p. 66, pi. XXII figs 6— 12. 1906. Euchsete barbata Brady. Pearson, p. 17.

1892
1894,

18

1903
1903.
1904,
1905

— — Brady. Giesbrecht, p. 246.
nee. — — — Th. Scott, p. 58.

— — — Giesbrecht & Schmeil, p. 40.

? — — — Thompson & A. Scott, p. 244.

nee. — — _ G. O. Sars, p. 41, pi. XXVIII.

1907. nee. — — — Danias & Koefoed, p. 409.
1907.? — — — G. O. Sars, p. 3.

1908. pars. — — — V. Bremen, pp. 54 — 55 fig. 61.
1908. — — — Farran, pp. 40—41, pi. Ill figs

13—14-

? — — — Wolfenden, p. 135. I 1909.? Pareuch;ete barbata Brady. A. Scott, p. 70, pi. XVIII

? — porrecta n. sp. G. O. Sars, p. 16. | figs 1—8.

Description, f?. Size of specimen from St 183 was 7-87 mm.; anterior division 575 mm.; uro-
.sonie 2'i2 mm. Another specimen measured 8-3 mm. Far ran' s specimens measured 8-i — 88 mm.

The shape of the body is practically like that of the preceding species; the ventral surface of
the abdominal somites are less heavily hirsute. The comparative length between the 3 first abdominal
somites is as 42, 24, 24; the genital somite is 1-3 as long as wide and scarcely i'3 as long as deep;

COPEPODA

175

the ventral protuberance is in lateral view scarcely different from E. Farraui ; the anterior process is
comparatively shorter, but the posterior margin and the dorsal lateral process are scarcely different.
In the transverse chitinous plate no median incision was found posteriorly; covered by this plate a
chitinous system was found with a median incision (text-figs 49 a — d).

Text-fig. 49. Eitchiete barbata Brady.

a-b. f9. Genital somite of two specimens in lateral view X 16. c. f9. Genital somite X 16. d. Vulva X 180. e. f 9- Pes I

dext. ant. view X 53. f-g- fd"- Lateral corner from the left and right X 18. U. fcj. Pes V dext. Re X 57- i- Pes V Ri sm.

from inner side X 59- j. Y9 (St. V) Abdomen X 18. k. Furca of same specimen X 33- 1- Yrf (St. V), Pes V X 33- m. \c?

(St. IV). Abdomen X 16. ". Yd (St. IV) Pes V X 57- o-p. Y (St. III). Rostrum and abdomen X 16.

The measurements of the antenmdae show in the examined specimens a slight difference from
E. Farraui; the segments 24^25 are slightly longer than, (not=) segment 19 and the segment 21 is
almost ri as long as 17 (not as long as). The Le of the maxillulae possesses in the examined specimens,
in addition to the usual 5 long setae, 2 shorter ones, showing from fairly long to very short variations.

176

COPEPODA

The pes I (text-fig. 49 e) is scarcely different. The pes II differs distinctly by the Se Re II, which al-
most extends to the end of the fairly long Se i Re III, and by the long Se 2, which extends to the
tip of the segment and to the base of the Se 3.

The anterior surface of the labrum shows an arrangement of the hairs most like that of E. Sarsi
(fig. 7 a). The oral surface is like that of E. Farrani; the lateral group consists of about 40 hairs, placed
inwards in two rows, and outwards in one; about the difference in the arrangement of the other
groups I refer to fig. 8 a. In the arrangement of the hairs on labial lobes etc. no features of great
interest were found.

c?. Size of specimen from St. 183 was 7-37 mm.; anterior division 5-3 mm.; urosome 2"07 mm.

The shape of the body is practically like that of E. norvegiea ; the rounded lateral corner is
more produced on the left side than on the right; the dorsal lateral process is more distinct on the
right side than on the left. The first abdominal somite has the dorsal process near the anterior border
prominent on the right side, and just indicated on the left (text-figs 49 f—g). The antenmilae reach
just beyond the end of the cephalothorax; the segments 12 — 13 being without any articular membrane
posteriorly on the left side, but with a fairly distinct articular membrane on the right side in some spec-
imens. No "^sthetasken" were found in segment 20. The segments 24^25 are I'l as long as segment
15. The antennae, mandibulae and maxillae scarcely show features of interest; the maxillulae have 8
setae in Ri, but do not differ from E. norv. in other respects. The maxilUpeds do not possess any
hooked process in the lob. IV of basipodite II, but 2 setae, of which the one is thicker. The Se of
Re I pes I is extremely short and delicate. The pes II differs by the short Se Re II, which does not
reach the middle of the third division. The pes Fdext. is scarcely different from E. norv.] it has a well
developed Se Re I, and trace of articular membrane between Re I and II. The pes Fsin. has the Re
II — III comparatively shorter than E. norv., and has the serrated process fairly pointed, rather shallow,
and with a few distal teeth, comparatively strong, as .shown in figure 8 b. The left endopodite is
rather clumsy and has only a single segment (text-fig. 49 i).

Yg (St. V). Size: 6-14 mm.; anterior division 4-6 mm. ; urosome 1-54 mm.

The lateral corner of the fifth thoracic somite, which is fairly well marked, is produced into a
rather blunt point. The first of the 4 abdominal somites is distinctly produced below in the females,
not in the single male. The appendages do not show features of great interest; the pes II is scarcely
different from that of the adult female. The pes V (text-fig. 49 1) is like that figured in E. tonsa, but
the St. are more developed. In a single female several of the furcal setae were more or less bifurcate
(text-figs 49 j — k). The two last abdominal somites bear ventrally groups of rather short hairs.

Yq (St. IV). Size: 4-49 mm.; anterior division 3-39 mm.; urosome i-io mm.

The lateral corners are sHghtly more pointed than in the preceding stage (text-fig. 49 m) ; the
first of the 3 abdominal somites is barely produced below; only a single tuft of hairs is observed
near the hinder border of the last abdominal somite ventrally. The appendages show differences similar
to those described in E. norv., f. inst, the segments 240^24 of the antennulae are 1-3 as long as the
segment 19 (text-fig. 49 n).

Y (St. III). Size: 3-06 mm. ; anterior division 2-37 mm.; urosome 069 mm.

COPEPODA

^11

H

Apart from the bigger size and more straight rostrum, the stage is scarcely different from that
of E. norvegica (text-figs 49 o — p).

Occurrence. The S/S Thor has "/^ 04 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire taken
9 f?, 2 fc?, 4 y? (V), I yc? (V), 2 y? (IV), i yc? (IV), i y (III) and '% 09 St. 180 6i°34 L. N. i9°03 L. W.
Yt. 1800 M.Wire i f?.

Distribution. Remarks. About the distribution of this species only very little is known, as will
be understood from the following remarks. By Farrran it has been recorded as occurring "in small
numbers on five stations of from 700 to xooo fathoms" off the west coast of Ireland. As neither Sars nor
Scott says anything about the characteristic tubercle on the left side of the genital somite, and as their
descriptions are not very perfect, I do not think that we should be right in including the Mid Atlantic
and the Indian Ocean within the range of this species. Far ran, with some reluctance, refers his species
to Brady's old species from 36° L. S. 46° L.W., on account of the corresponding size and similar structure of
pes II; Brady's figure of the genital protuberance and the smooth ventral surface of the abdominal somites
III — IV seems to me to speak against the correctness of this view. The same opinion is shared by Wolf-
end en, who regards E. barbata as more related to E. Wofendenii than to any other (cf. 191 1, p. 300); as,
however, the name is now applied to a well defined species, and as there is no reason to hope for a
sure identification, I prefer to follow Far ran in this respect.

51. Euchaete Sarsi Farrau.
(PI. VI figs 7 a — b; text-figs 50 a — f.)

1908. Euchaete Sarsi n. sp. Farraii, p. 41, pi III figs 15—16.
1909? — — Farr. A.Scott pp. 75-76, pi. XXI figs 9—15.

Description. ?. Size of specimen from St. 183 was 10 mm.; anterior division 7-3 mm.; urosome
27 mm. Farran's specimens measured 9-8— 10-2 mm.

The shape of the body etc. scarcely .show features of interest. The anterior division is 27 as
long as the urosome; the proportional length of the abdominal segments is 45, 27, 27. The genital
somite has not on the left side the characteristic tubercle found in E. Farrani, and the ventral pro-
tuberance has the anterior process slightly concave in the middle, and the posterior process less
prominent than in the other species (text-figs 50 a— e). The vulva is in the ventral surface quite dif-
ferent from that of E. Farrani and barbata. The median chitinous plate has posteriorly a median
incision, but the area in front is irregularly wrinkled, and the triangular plate is only indicated; the
trilobate process is very indistinct (text-fig. 50 f). The segment 19 of the antennulae is ri as long as
24 00 25. The Le of the maxillulae possess 2 extremely short and one longer seta proximally, and in addi-
tion to these the usual long ones distally. The pes I has a very short Se Re I. The Se of Re II extends
to the end of Se i Re III, and the Se 2 Re III extends somewhat beyond the middle of the third division.

The anterior surface of the labruin is distinctly different from that of E. norv. and Farrani, as
realised by comparing fig. 7 a and the description of E. norv. The oral surface of the labrum is very
much like that of E. norv. The lateral group consists of 30—40 short spines; the groups 1—2 are placed
near to each other; the 3-5 are fairly well separated. The arrangement of hairs in front of lamina

The Ingolf-Expedition. III. 4. ^

178

COPEPODA

labialis is most similar to that of E. Scott i (fig. lob); the large lateral group is almost completely fused
with the median, which, however, has longer hairs.

c^. Size: 8-3 mm.; anterior division 5-5 mm.; urosome 2-8 mm.

The rostrum is directed more forwards than in E. barbata Brady; the lateral dorsal teeth of
the last thoracic tergite are only slightly developed. The antennulae extend distinctly beyond the end
of the cephalo-thorax; the segment 20 has a well developed "^sthetask"; in other respects these organs
are scarcely different from those of E. barbata. The niaxillipcds have in the lobe IV of Basp. II a well
developed, rather slender, hairy conical process, which terminally is produced into a delicate lash. The Se
of Re I pes I is wanting. The pes II is practically like that of E. barbata. The pes V dext. is scarcely
different from that of E. barbata ; the pes V sin. is in most respects like that of the other species ;

Text-fig. 50. Etichcete Sarsi Fairan f?-
a— e. Abdomen of different specimens X 16. f. Vulva in ventral view X iSo.

the differences are best realised by comparing figs 7 b and 8 b; the best character is found in the ser-
rated process which is more slender, and has a less regular serration.

Occurrence. The S/S Thor has taken this species at the following deep sea stations.

"/7 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 3 f?.
'% 1904 St. 180 6i°34 L. N. i9°03 L. W. Yt. 1800 M. Wire i f ?.
378 1905 St. 167 57°46 L. N. 9°55 L. W. Yt. 1500 M. Wire i f d".

Farran has recorded this species from three deep sea stations off the west coast of Ireland.

Remarks. That the described females are identical with E. Sarsi Farran, I regard as quite evi-
dent; in contrast to Farran I do not regard it as identical with Wolfenden's E. barbata (cf. p. 174). The
described male is certainly different from that which has been referred to E. barbata, and belongs cer-
tainly to E. Sarsi or another species of similar size nearly related to it. I do not think that the male,
which A. Scott refers to E. Sarsi is identical with the described one, on account of the well developed
lateral dorsal teeth of the fifth thoracic tergite and the different shape of the serrated process.

COPEPODA

179

52. Euchaete Scotti Farran.
(PI. VI figs 10 a — c; text-figs 51 a— j.)

190S. Euchcete Scotti n. sp. Farran, p 42, pi. Ill figs 11 — 13.

191 1.? — — Farr. Wolfenden, pp. 301 — 302, pi. XXXV fig. 2, text-figs 533—0.

Description. f$. Size of specimen from St. 183 was 5-99 mm.; anterior division 4-36 mm.; iiro-
some 173 mm. Farran's specimens measured 57— 6-3 mm., Wolfenden's specimens measured 4-3 —
4-85 mm.

The shape of the body is more robust than in the preceding species, as the anterior part is
only c. 2'3 as long as wide, and as wide as the urosome is long. The lateral corner of the cephalo-
thorax is not quite regularly rounded, but somewhat triangularly produced; the anterior division is 2-5
as long as the urosome, which shows the following proportion between the three first somites (15, 8-5,

e I

Text-fig. 51. Euchate Scotti Farrau.
a— d. f9. Genital somite >; 18. e. f9. Vulva from below X 180. f. fd". Left corner X iS. g— li. Y^—(S (St. V). Abdomen
from the left X 24. i. Ycf (St. V). Lateral corner X i5- j- Yd (St. V). Pes V X I5-

8-5). The genital somite, which is 13 as long as wide and 1-2 as long as deep, is in dorsal view slightly
asymmetrical, and has the lateral margins strongly convex, somewhat in front of the middle. The
genital protuberance has in lateral view a wing-like anterior process, sometimes slightly concave in the
middle, and a more dorsal and posterior process, separated from the former by a distinct incision (text-
figs 51 a— e). In ventral view the vulva shows some .similarity to Wolfenden's figure 53 a, which is,
however, too incomplete for a detailed comparison, and is distinctly different from the mentioned
species of this group. The posterior incision in the median plate is not observed; the anterior tri-
angular point, of which an oval plate is found, is just indicated.

The antennulae extend just beyond the end of the third thoracic tergite, but not to the end of
the cephalo-thorax ; the segments 24cn3 25 are as long as the segment 19; the appendages scarcely show
differences from those of E. norvegica. The mouth-limbs are scarcely different from those of E. barbata;

23*

j8o copepoda

the Le of the viaxilhdac possess 5 long -f 2 shorter setae. This is in contrast to Wolfenden, who has
only found 5 setae in his specimens. The articular membrane between Re I— II of pes I is barel}- in-
dicated, and the Se is, as pointed out by Wolfenden and Farran, extremely minute. The pes II \s
like Farran's description; the Se Re II almost extends to tlie end of Se i Re III, and the Se 2 Re III
extends a little beyond the middle of the third division; in most of Wolf en den's specimens the Se 2
reaches the end of the segment.

The anterior surface of the lahrum is in the arrangement of the setae scarcely different from
E. Sarsi (fig. 7 a); the oral surface is most like that of E. norvegica (fig. 10 a); the lateral group consists
of about 10 fairly long, densely placed, setae. The first group of the longitudinal series, which is some-
what convex in front, is connected with group 2, which possesses fairly long setae, by delicate hairs
scattered inwards and outwards; groups 3—6 are fairly well separated, without difference between outer
and inner portion. The arrangement of the hairs on the area in front of the lamina labialis (fig. 10 b)
is in the main like that of E. norvegica, but shows, however, as realised by comparing figures, distinct
difference; the lateral group, f. inst, is almost completely fused with the median.

c?. Size of specimen from St. 183 was 5-56 mm.; anterior division 3-93 mm.; urosome 1-63 mm.

The shape of the body is more clumsy than in E. norvegica; the anterior division is only 25
as long as wide, and 2-4 as long as the abdomen, the first somite of which is about i-i as long as
broad. The left side of the thorax is distinctly produced, and the dorsal lateral spine is represented
by a minute rounded eminence; on the right side no lateral spine is found (text-fig. 51 f). The dorsal
lateral process of the first abdominal somite is, as usually, best developed on the right side, but is not
very prominent The anfennulae extend distinctly beyond the end of the cephalo-thorax ; segments 12 — 13
have no articular membrane posteriorly; the segment 19 is 1-9 as long as 240325; no "^Esthetask" was
found in segment 20. The lob. IV of the Basp. II of the maxillipeds has in addition to a fairly long
slender seta a moderately long hairy process and a rather small conical protuberance; the other mouth-
limbs are scarcely different from those of the type-species. The pes I has an extremely short Se in Re I;
the pes II is like that of E. larbata.

The pes V is shorter and more clumsy than in the mentioned species; the Re I — II pes V sin.
are most like the corresponding segments in E. harbata (fig. 10 c); the serrated process is narrow with
regular marginal serration.

Yq (St. V). Size of $ from St 183 was 4-83 mm.; anterior division 3-63; urosome 1-2 mm. c?
(St. 183) measured 4-54 mm.

The shape of the body is, as in the adult specimens, more clumsy than the corresponding stages
of the related species. The lateral corner is, as shown in figure, triangularly, but obtusely, pointed. The
Se of the Re I pes I is comparatively long and slender. The females examined are distinctly different
from the male by the produced lower margin of the first somite; the pes V does not show characters
of great interest (text-figs 51 g — ^j).

Y$ (St. IV). Size of specimen from St 183 was 334 mm. ; anterior division 2-48mm. ; urosome
0-86 mm.

This stage differs from corresponding stage in related species by an obtusely pointed lateral corner.

Occurrence. The Thor Expedition has gathered this species at two stations only viz:

COPEPODA

i8i

"/; 1904 St. 183 6i°3o L. N. i7°o8 L. W. Yt. 1800 M.Wire 37 f? (3 with egg-balls, 2 with sperm.), 8 fc?,

8y?(V), 4yc? (V), ly? (IV).
=^4/5 1904 St 104 62°47 ^- N. i5°03 L. W. Yt. 1500 M. Wire 4 f ?.

This species has previously been gathered off the west coast of Ireland "at depths of from 700
to 1000 fathoms" at five stations "but very few specimens were found on each occasion". Wolfenden's
specimens, which on account of the different shape of the genital somite (PI. XXXV fig. 3) cannot with
security be referred to the same species, were gathered under the equator ca. 20° L,. W. (depth 3000 m.)

53. Euchaete Hansenii n. sp.

(Text-figs 52 a — b.)

Description. Size: 8-9 mm. ; anterior division 6-5 mm.; urosome 2-4 mm.

The shape of the body is like that of B. norvegica. The anterior division is 27 as long as the
urosome, which is only a little longer than the width of the thorax. The proportional length of the
abdominal somites is 45, 26, 25. The genital somite is, laterally, more suddenly convex than in E. Sarsi,
and, as in this, the greatest width lies in the proximal part; the genital somite is 1-3 as long as
wide, but only i-i as long as deep.
The lateral conical process which
characterises E. barbata and Farraiii,
is wanting. In lateral view the geni-
tal protuberance differs distinctly
from that of E. Sarsi by the straight,
not concave, anterior process, and by
a fairly distinct process behind and
above the second one, sometimes
indicated in E. Sarsi, which, as usu-
ally, represents the posterior border
of the vulva. The ventral surface
is quite different; the triangular
plate in front is divided into three
processes; the transverse plate has
posteriorly a median incision, on each
side of which are two lobes (text-figs

52 a— b). — The a?ttennulae scarcely extend to the end of the cephalo-thorax ; the appendages are
scarcely different from those of E. norvegica; the segment 19 is ri as long as the segments 24<>^25.
The maxillulae possess in Le i two basal, fairly long and slender, setae, followed by 6 powerful seta
and one terminal somewhat shorter one; the Basip. has 5, the Ri I 3, Ri II 4 and the Ri III 3 setae.
The articular membrane between Re I— II is barely indicated, and the Se is long and slender. The Be
of Re I is fairly long, and extends almost to the base of Se i Re III, and the Se 2 Re III extends to
the base of Se 3.

Text-fig. 52. Ettchccte Hansenii n. sp.
a. fQ. Abdomen X i6. b. Vulva in ventral view X 180.

l82

COPEPODA

Remarks etc. Of this species the S/S Thor has ^^/g 1905 St. 165 6o°oo L. N. io°35 I^. W. taken
a single mutilated female. This species is nearly related to E. Sarsi^ but it easily distinguished by the
smaller size, by the structure of the genital somite, by the 9 setae in the Le of the maxillulae, and
by the well developed Se Re I pes I.

54. Euchaete Bradyi n. sp.
(Pi. VI fig. 9 a; text-figs 53 a — b).

Description. vSize: 80 mm.; anterior division 5-5 mm. ; iirosome 2'5 mm.

The anterior division is about 2'2 as long as the urosome, which is about as long as the
abdomen is wide. The lateral corner is rounded, with a heavy tuft of hairs. The proportional length

between the abdominal so-
mites is 40, 25, 25. The ventral
surface of the three last ab-
dominal somites possesses a
number of short delicate hairs.
The genital sojiiitc is i-6 as
long as wide, but, on account
of the high ventral protuber-
ance, only i-i as long as deep;
no posterior process is found
on the left side. The snbapical
seta is broken, but is probably
longer than St. 2. The ante-
rior flange on the side of the
vulva is rather short, with
a somewhat convex outline, when observed in lateral view; the posterior margin is rather prominent.
The vulva is covered by the lateral flanges, in any case in front, to a greater extent than in the other
species; the triangular plate in front is indistinctly developed; posteriorly a median incision is found,
on each side of which a complicated chitinous framework is found (text-figs 53 a — c).

The antennulac extend somewhat beyond the end of the abdomen; the appendages are like
those of E. norvegtca; the segments 24cn3 25 are i-i as long as segment 19. The Le of the maxillulae
possess two short and 5 long setae; the basipodite has 5, and the Ri 3 -]- 4 -(- 3 setae. The other mouth-
limbs do not show features of any interest.

The articular line between Re I — II pes I is indistinctly marked; the Se Re I is wanting, and
the concavity distal to its usual insertiou is only moderate. The exterior outline of the Re III, which
in most species is more or less straight, is moderately convex towards the middle, and tiie usual
glandular pore is not seen. The Se Re II of the pes II extends almost to the tip of the Se i Re
III, and the Se 2 of this segment extends somewhat beyond the middle of the third division, but not
to the end of the segment.

Text-fig. 53. Euchcete Bradyi n. sp. fQ.
a— b. Abdomen X l6. c. Vulva from below X 180.

COPEPODA

183

The anterior surface of the labruin has on each side, posteriorly, an area covered with fairly
long hairs; this group is almost fused with a transverse row of rather short hairs, which, without
interruption, is continued from right to left. The oral surface has in the lateral group 40—50 short
spine-like hairs placed in a curved row; in the middle two distinct transverse rows, as seen in fig. 9 a.
The groups I— II, in the longitudinal series, meet as in Euc. norv. under an angle; the groups
III— IV have a smooth area in the middle, while the groups V— VI are compact The groups of hairs
in front of the lamina labialis are in most respects like fig. 3 b, but the lateral posterior group is more
elongate, and consists of fewer hairs.

Remarks etc. Of this species I have only examined a single female, taken ^4/^ 1896 St. 118
68°27 Iv. N. 8°20 Iv. W. Closing net 1030 fathoms by the Ingolf Expedition; it is probably nearly related
to E. barbala, but differs distinctly from it by the deep genital protuberance.

55. Euchaete bisinuata G. O. Sars.
(PI. VI figs II a— e; text-figs 54 a— j).

1907. Eucheete bisinuata u. sp. G. O. Sars, p. 12.

1908. — — G. O. Sars. Farran, p. 45, pi. Ill figs

17—19. Pl- IV fig. 4-

1909. Euchsete bisinuata G. O. Sars. A. Scott, pp. 70—71, pl.

XVI figs 10—17.

Description, f?. Size: 5-62 ram.; anterior division (2-58 -(- 1-59) == 4-17; urosome 1-45 mm. Sars'
specimens measured 5-2 mm.; Scott's 5 mm.

The anterior division, which is distinctly twice as long as the urosome, is rather short and
clumsy with the lateral corners regularly rounded.

The genital somite is, seen from above, slightly asymmetrical with a well marked convexity
in front, somewhat behind the base of the somite (text-figs 53 a— c). The ventral outline shows 3
characteristic lobes, as figured by Farran and ScotL The posterior border of the vulva is formed
by a transverse, somewhat hollowed, ridge, which is gradually sloping forwards. In front of this, and on
each side are a median and an anterior laminous process, of which the latter is the longer and thinner; the
processes on the left side are comparatively shorter, and are placed more posteriorly; in ventral view they
are seen to be turned towards the middle, thus partly covering the vulva. The third and fourth somites
are almost smooth, and without any hairs below, in contrast to the fifth somite, which has ventrally a
tuft of hairs; it is dorsally almost completely covered by the preceding tergite. The subapical seta is
thinner but not very much longer than the St. 2, and it is not geniculated.

The antenmdae extend almost to the tip of the anterior part; they are in the main like E. norv.,
but the segments 240^25 are just as long as segment 20, and 23 is a little longer than 16, which is as
long as 17. The antennae and mandibulae do not show any features of interest. The Le i of the inax-
iUulac bears 6 bristles of almost equal width basally, but the distal bristle is much shorter than the others,
which are much longer thau tlie breadth of the maxillulae. The Li i has the usual 10 hairs anteriorly,
but only two posteriorly; the Li II as well as Li III is well developed, and each bears a long seta. The
basipodite III has 3 setae with short hairs, of which the distal is the longest. The Ri I has 2 rather
slender and a single powerful seta, while the Ri II >= III have 4 powerful ones. The convexity of the
exterior margin in the basal segment of the maxillae is just indicated (text-fig. 54 d). The /^j / has

i84

COPEPODA

only the limitation between Re I — II indicated, where the mnscle is fastened inwards; the articulation
between the Re II and III is well marked anteriorly, but only indistinctly so posteriorly (text-fig. 54 e).
The exterior border has a well marked concavity (as shown in Farran's fig. 18 in contrast to Scott's
fig. 15) and a long and slender Se i, almost reaching the base of Se 2. The pes II is like the figures
of the two authors; the Se Re II scarcely reaches the end of the Se i Re III, and Se 2 Re III scarcely
reaches the end of Se 3.

The epistoma and the anterior surface of the lahruDi are scarcely different from those of E. norv.

The oral surface of the labruiii (fig. 1 1 a)

a b c e

shows a distinct difference from that of
E. norv.^ as is realised by comparing fig-
ures; the most characteristic feature is the
lateral position of the first group, in front
of which, behind the marginal fringe, a
granular area is found. The usual spinous
area behind the median spot Nr. 4 is
wanting. The laiiii/ia labialis is, as seen
in fig. II b, somewhat different from
E. norv., but more interesting is the large
lateral group of hairs almost completely
fused with the median group, situated in
front of the lamina. The lobus labialis has
the posterior lateral group well developed.

d*. Size: 4-8 mm.; anterior division
(2'2 + i'4) = 3'6 nmi. ; urosome 1-2 mm.

The body is rather clumsy, and about
3 times as long as the urosome; no dif-
ference was found between the lateral
corners on the right and left side, and
no tooth was observed. The genital so-
Text-fig. 54. Eiichiete bisinuata G. o. Sars. mite is distinctly asymmetrical, as it is

a. f9. Abdomen X 18. b-c. fQ- Furca X 18 and 57. d. f9. Maxilla dext. produced behind on the right side. The

from behind X 57- e- f9- Pes I X 57- f- f cf- Pes V in anterior view

X75. g-h. y 9-0? (St. V). Abdomen X 16. j. yd (St. V). Pes V X 57- subapical Seta is as usual in the male

short and thin.

The viaxillulae are as a whole less developed than in the male of E. norv.., and differ in minor
points. The Le I has, in addition to the 5 long setae, a delicate basal one, and the Basp. has only a
single seta. The Basp. II of the maxillipcds has in the lob IV only a single hair in addition to a
hooked clumsy organ surrounded by delicate hairs (fig. 11 c).

The pes I has no Se in the first segment, which is well separated from the second by a com-
plete articular membrane; the Se 2, which is short and strong, is placed on the somewhat produced
exterior corner of Re II. The pes II has, in contrast to the female, the Se Re II very short

COPEPODA 185

and the Se 2 Re III does not reach the end of the segment. The pes V (fig. 54 f) resembles in most
respects that of E. norv. The Ri dext. is long and slender, consisting of a single segment, bnt divided
into two, about equal, divisions (of which the posterior is the more slender) by an exterior rounded emi-
nence, which is indicated in E. glacialis. The Re I (v^ II of the right leg, which is 1-5 as long as the
Re III, shows by an indistinct incision indication of subdivision into a ba.sal and a terminal segment;
a small Se Re I is found. The Ri sin., which is short and club-shaped, shows trace of segmentation
only towards the tip, and has terminally a very minute spine. The tip of the left exopodite is, as seen
by comparing the figures (PI. VI figs 11 d— e), hke that of E. norv.^ but differs distinctly by the short
and clumsy form of the serrated interior lobe with two distal rows of larger and smaller teeth con-
verging towards the end, and by the comparatively long hairy appendage (text-fig. 54 f).

Y^ (St. V). Size: $ 4-11 mm.; anterior division (2-09 -|- I'Oi) = 3-1; urosome I'Oi mm.

In two female specimens the first abdominal somite is distinctly produced below, in a single
male scarcely so (text-figs 54 g — h). The measurements of the antenniilae and the structure of pes I — II
are scarcely different from those of adult females. The pes V c? does not provide features of great
interest (text-fig. 54 j).

Y$ (St. IV). Size: 3-36 mm.; anterior division 2'5 mm.; posterior o-86 mm. A single female, which
ought perhaps to be referred to tliis species, was examined.

Occurrence. The S/S Thor has taken 'V7 1904 St. 183 61^30 L. N. i7°o8 Iv.W. Yt. 1800 M. Wire
9f?, 4fc?, 2y? (V), I yd' (V), i y? (IV).

It has previously been recorded by Sars from several stations, from the Monaco Expedition, by
Far ran "in small numbers at three stations" off the west coast of Ireland as far north as 55° N.
(io°45 W.) "at depths between 700 and and 1150 fathoms", and by Scott, taken by the Siboga Exp.,
from 5 stations (i — 2 specimens) in considerable depths.

Remarks. As the described males and females were found together, as they corresponded fairly
well to each other in size, and as I did not find any species to which the males are more naturally
referred, I have referred them to the same species, in spite of a rather curious difference found in the
structure of pes I. The young specimens, on account of rounded lateral corners, size and similar
structure of pes I— II, were referred to the same species.

In spite of minor differences from Sars' and Scott's descriptions, scarcely any doubt can exist,
that the specimens examined by the different authors belong to the same species.

56. Euchaete gracilis G. O. Sars.
(Text-fig. 55.)

1894. Euchnite barbata Brady. Th. Scott, p. 5S, pi. VI fig. 17- ; 191 1- Euchsete quadrata Farraii. Wolfeuden, pp. 297-29S, fig.
1905. - gracilis n. sp. G. O. Sars, p. 16. 39, Taf. XXXV fig. i.

1908. — quadrata n.sp, Farran, p. 43, pi. Ill figs 20— 21. |

Description, f?. Size of specimen from St. 88 was 674 mm.; anterior division (276 + 1-96) =
472 mm.; urosome 2-02 mm. Sars' specimens measured 6-6, Farran's 6-9, Wolfenden's 5-85— 6 mm.

The shape of the body is practically like that of E. norvegica. The lateral corners are not
regularly rounded as stated by the authors, but somewhat squarely truncate (text-fig. 55). The genital

The Ingolf-Expedition. III. 4. ^

i86

COPEPODA

somite, which is distinctly shorter than the following two, but 1-5 as long as the second, has a very
prominent and characteristic genital protuberance. The vulva is surrounded by a chicinous system
distinctly more complicated than figured by Wo If en den; more exteriorly, along the lower margin,
is found on each side a chitinous plate pointing forwards, which, somewhat in front of the middle, possesses
a short, rounded process (cf. Wolfenden). As stated by Wolfe nden, in contrast to Sars and Farran,
hairs were found on the ventral surface in the third and fourth abdominal somites in most specimens.
The antennulae extend scarcely to the end of the thorax; the appendages are scarcely different
from those of E. norv., and the measurements are not very characteristic; the segment 20 is as long
as the segment 24 <N3 25, and the 23 as long as the 16. The antennae and mandibulae are scarcely dif-
ferent from those of E. norv., while the maxillulac, as pointed out by Farran, possess, in the Le 9
bristles, of which the 2 proximal are moderately short; the Basp. Ill has four setae and the three seg-
ments of Ri have three setae each. The maxillae and maxillipeds are like those of E. norv., but the
latter differ by the more slender spines of Ri.

The articulation between the Re I and II of pes I is anteriorly indicated outwards, and posteri-
orly inwards; the Se Re I is represented by a small protuberance. The Se Re II
pes II extends almost to the tip of Se Re III, and the Se 2 extends just to the
base of Se 3.

The shape of the epistoma is scarcely different from that of E. norv.
The anterior surface of the labruvi has the hairs somewhat differently placed;
anteriorly, in the middle, a transverse row of short hairs is found, in addition to a
more lateral group of rather long setae; laterally and more posteriori}- an area
Text-fig. 55. Euchste covered with densely placed short spines is observed. The oral surface of the

^ "^ ' ■ ■ labrutn and the labial lobes are scarcely different from E. norv., and the area in

Abdomen X 16.

front of the lamina lahialis only differs by less regular lateral groups of hairs.

Occurrence. The Ingolf Expedition has not taken this species, but it has been gathered by

the Thor at the following stations.

"/; 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M.Wire i f?.

'5/6 1905 St 82 5i°oo L.N. ii°43 L. W. Yt 1200 M.Wire 3 f ?.

8/6 1905 St. 72 57°52 L. N. 9°53 L. W. Yt 1500 M. Wire i f ?.

2°/6 1905 St 88 48°09 L. N. 8°30 L. W. Yt 300 M. Wire 5 f? (2 with sperm).

^761905 St 90 47°47 L. N. 8°ooL. W. Yt 300 M. Wire 2f?.

This species "was taken in small numbers on five stations at from 350 to 700 fathoms" off the
west coast of Ireland. It has also been gathered by the Prince of Monaco and the Gauss at several
stations in the Mid-Atlantic.

Remarks. This species is probably identical with Sars^ E. gracilis, as no difference was found
between my specimens and Sars' rather incomplete description. From A. Scott's description it differs by
the shorter antennulae and the hairy ventral surface of the abdominal somites III— IV. From Wolf endeu's
description of most of his specimens it differs by 9 instead of 7 setae in Le of the maxillulae, and by
the comparatively shorter Se 2 Re III pes II; as, however, one of Wolf en den's specimens had compara-

COPEPODA

187

tively long antennulae and comparatively short Se 2 there is reason to suggest that the value of these
characters ought not to be exaggerated.

57. Euchaete acuta Giesbrecht.
(PL VI figs 12 a— c; text-figs 56 a— b.)

1892. Euchtete acuta n, sp. Giesbrecht, p. 246, Taf. 16 and 37. I 1905. Euchfete acuta Giesbr. Esterly, p. 157 fig. 23.

i»9».
1903.

1903-
1904.
1904.
1905.
1905.

Giesbr. Giesbrecht & Schmeil, p. 38.
J. C. Thompson, p. 18.
J. C. Thompson & A. Scott, p. 244.
Wolfenden, p. 1 1 1.
Cleve, p. 190.
G. O. Sars, p. 4.
Farran, p. 35.

1906.
1908.
1 90S.
1909.
1909.
1911.
1912.

Pearson, p. 17.

Farran, p. 40.

V. Bremen, p. 51, fig. 56.

A. Scott, p. 65, pi. XX figs 1-9.

Pesta, p. 23.

Wolfenden, p. 299.

Pesta, p. 22.

Text-fig. 56. Euchiete acuta

Giesbr. Yc? (St. V).

a. Abdomen X 18. b. Pes V

in anterior view X 33-

Description. i% Size: 4-02 mm.; anterior division (17 + 0-97) = 2-67 mm.; urosome 1-35 mm.
Giesbrecht's specimen measured 4-1 mm., Farran's 4-4 mm. and Scott's 4-2 mm.

The genital area has on each side of the vulva a lamina-shaped process, somewhat larger on
the right side; the outline i.s, as shown in fig. 12a, somewhat different from Giesbrecht's fig. 47 (Taf. 37).
Scott's fig. 4 of the abdomen in dorsal view differs distinctly by the presence
of a right lateral process (may possibly be the process on the right side of the
vulva, which is visible when the animal is not examined in complete dorsal
view). The subapical seta is much longer than the St. 2.

The antennulae, mouth-limbs and natatory limbs are scarcely different
from Giesbrecht's description.

The epistoma and the anterior surface of the labrum do not show any
features of interest. The hairs on the oral surface of the labrum show a rather
simple arrangement. The group i is, as usual, placed somewhat laterally, but
is not distinctly separated from the group 2; the groups 3—4 are small and well
marked out; the groups i^ fairly big. The transverse row behind the median spot Nr. 3 is .short and
narrow. No lateral group was observed (of. fig. 12 b). The lateral group in front of the lamina labialis
(fig. 12 c) consists of small granules, and is well separated from the median groups; these consist, as
shown in fig., of fairly long hairs; the inner group of granules anteriorly was not observed.

Yd' (St. V). Size: 372 mm.; anterior division 2-68 mm. ; urosome 1-04 nmi.

The lateral corners are rounded. The subapical setae are, as in the adult females, stronger as
well as much longer than the St. 2. The antennulae extend scarcely to the end of the anterior division.
The appendages are scarcely different. The structure of \h& fifth foot is seen in text-figs 56 a— b.

Occurrence. The species was not gathered by the Ingolf Exp.; but, as it was found by the Thor
at the following 3 stations, I have included it here.

•5/6 1905 St. 82 5i°32 L.N. ii°43 L. W. Yt. 1200 M. Wire if?.

2% 1905 St. 88 48°09 L. N. 8=30 L. W. Yt. 300 M. Wire 15 f ? + i yd*.

"/6 1905 St. 90 47°47 L.N. 8°oo L. W. Yt. 300 M.Wire if?.

24*

i88

COPEPODA

Distribution. This species has been taken off the west coast of Ireland, in the Mediterranean,
in the South Atlantic as far south as 25° L. S., in the Indian ocean, and in the Pacific.

58. Euchaete hebes Gicsbrecht.
(PI. VI figs I3a-b; text-Hg. 57.)

1S88. Euchffite hebes n. sp. GiesbrecUt, p. 337- j I9°5- Euchaete hebes Giesbr. G. O. Sars, p. 4.

1S92. — — Giesbr. Giesbrecht, p. 246, Taf. 15 and 37 ! 1906. — — — Norman & Scott, p. 128.

figs 15-16. ! 1908. _ _ _ V. Bremen, pp. 51-52 fig. 57.

1894.? — — — Th. Scott, p. 59, p!. VI figs 18 — 19. 1 1909. _ _ _ Pesta, p. 24.

1S9S. — — — Giesbrecht & Schmeil, p. 39. 1910. _ _ _ Steuer, p. 24.

1903. — — — Lo Bianco. j i9"- — — — Farran, pp. 94— 95.

1905. _ _ — Gough, p. 336, figs 4—7. I 1912. _ _ _ Pesta, p. 22.

Description, f?. Size: 3-54 mm. ; anterior division (1-56 + 0-99) = 2-55 mm.; nrosome 099 mm.

Giesbrecht's specimens measured 285 — 2-95 mm.

Near the lateral margin of the last thoracic somite is found, dorsall\-, a membranous fringe bearing

short hairs; it is not equally prominent in all specimens, but generally more so than shown in fig. 13 a. The

abdominal somite I <n) II has, dorsalh', a characteristic process, and, on each side of the

vulva lamelli-form processes more developed, on the right side. One of the 6 apical setae

of the maxillae shows the structure characteristic of Pareuchatc with several short

teeth and a few larger branches. The number of glandular pores in the legs scarcely
Tcxt-fifif. S7«
Euc/ueiehebes Gbt. differs from those of E. norv., except by the absence of any pore at the base of Se i Re III.

YdT (St. V). Pes V The epistoma and the outer surface of the labrum are in main features like

X 39.

those of E. norv. The oral surface has the two first groups placed rather longitudinally,

and the three following ones fairly well separated. The area in front of the lamina labialis is, as shown

in fig. 13 b, rather characteristic, especially by the lateral group of hairs, which is a longitudinal series

in continuation of the serrula 6-dentata.

c?. Size: 3-03 mm.; anterior division (i'35 h 078) = 2-13 mm.; urosome 0-9 mm. Giesbrecht's
specimens measured 275 mm.

Lateral corners are rounded and somewhat more produced on the right than on the left side;
on both sides is, dorsally, the usual fairly well developed tooth. The first abdominal somite has on each
side, dorsally, a similar tooth as in E. norv. The ajifcnmilae reach distinctly beyond the end of the
cephalo-thorax; the segments 12 — 13 are, posteriorly, indistinctly separated, and more so on the left side.

The Re I of pes V has a fairly well developed Se.

c? (St. V). Size: 2'68mm.; anterior division (1-19-1-075) = 1-94; urosome 074 mm.

The lateral corners of the thorax are regularly rounded without the mentioned hairy fringe.
The subapical seta of the furca is onl\' a little longer than the St. 2. Pes V differs from E. norv. by a
more rounded Ri sin.; the outlines of the exopodites are, as realised by comparing text-figs 471 and
57, somewhat different.

Occurrence. Within the area explored by the Ingolf Exp. this species has uot been taken; but,
as it has been gathered by the S/S Thor "/e 05 St. 90 47°47 L. N. 8°oo L. W. (viz: 23 f? (2 with egg-
sacs), 2 fc?, I yd* (V)), I have included it here. As the species has only been found in the Mediterranean

COPEPODA

189

and the East Atlantic, especially with moderate frequency off the month of the English Channel, and
as it has not been recorded by Farran from the west coast of Ireland, Farran is probably right in
regarding it as a member of the Mediterranean fauna in its wider sense (of. p. 95).

Scolecithricidae.

59. Scaphocalanus magnus Th. Scott.
(PI. VII figs 8a-d; PI. VIII figs 6a-g; text-figs 58 a-k.)

1S93. Amallophora magna 11. sp. Th. Scott, p. 55, pi. VI figs 5-9.
1894. Scolecithrix cristata n. sp. Giesbrecht, pp. 252,Taf. II— III.
1898. — — Giesbr., Giesbrecht & Schmeil, p. 48.

igoo. Scaphocalanus acrocephalus n. sp., G. O. Sars, p. 36, pis

VII- IX.
1903 Amallophora magna Scott. G. O. Sars, pp. 51 — 53, pis

XXXIV— XXXV.
1903. 9 nee. cT Scolecithrix cristata Giesbr., J. C. Thompson,

p. 21.

1905. Amallopbora magna Scott. G. O. Sars, p. 5.

1905. Scolecithrix cristata Giesbr. Farran, p. 36.

1906. — magna Scott. Esterly, p. 66, pis 9, 11 — 13.

1906. Amallophora — — Pearson, p. 17.

1907. — — — Koefoed & Damas, p. 410.

1908. Scolecithrix — — Farran, pp. 51 — 52.

1908. — — — V. Bremen, p. 76 fig. 89.

1909. Scaphocalanus magnus Th. Scott. A. Scott, p. 97.
191 1. Amallophora magna Scott. Wolfenden, p. 262.

1904. Amallophora magna Scott. Wolfenden, p.m. 1913- — _. _ Stephensen, pp. 313—314.

Description. f$. Size of .specimen from Thor St. 183 was 5-23 mm.; anterior division 4-08 mm. ;
urosome 1-15 mm. Sars' specimens measured 5 mm., Giesbrect's and Scott's 4-5 and Wolfenden's
37 to 4-25 mm.

The lateral corners of the thorax are triangularly produced and more or less rounded; but the
shape is, however, as seen in text-figs 58 a — i, rather variable, and in some specimens rather suddenly
produced. The third basipodite of the niandibidae is less elongate than figured by Sars, and has two,
not one, setae interiorl)-; the first inner segment has two terminal setae, and the second has nine. The
viaxillulae are scarcely different from Sars' figure; the third basipodite has five setae as shown in
Giesbrecht's fig. i PI. Ill, not 4 as mentioned in the text. The Li i bears 10 setae anteriorly and 3
posteriorly. The maxillae and maxillipeds scarcely differ from Sars' figures.

The second pair of legs shows a few features not mentioned in Sars' description. On the anterior
surface of the three outer as well as of the three inner segments groups of short teeth are observed;
the first inner segment has, as seen in fig. 8 b, a small outer tooth, which was, however, wanting in
another specimen. The first outer segment shows also a few spines on the posterior surface. The an-
terior surface of the third as well as the fourth foot is, as mentioned by Giesbrecht, covered all over
with small teeth. The marginal setae of the second basipodite in the fourth pair of legs are poorly
developed or wanting. Glandular pores were not observed, except one in the outer margin of the third
outer segment of the first pair of legs. The fifth pair of legs is in most specimens like that figured
by Sars, but it is often rather asymmetrical, and the outer seta extends sometimes beyond the end of
the segment, and is sometimes much shorter.

The elevation in front of the labrum, corresponding to the antennal segment, is slightly raised
(PI. VII fig. 8 a); the labrum proper, which is produced in front as a rounded protuberance; is by an

igo

COPEPODA

anteriorly convex line divided into an anterior and a posterior smaller part; the labrum proper is beset
with a number of shorter and longer bristles, the somewhat complicated arrangement of which is most
easily understood by studying fig. 8 c.

The oral surface of the labnim (PL VII fig. 8 d) shows a rather characteristic structure; the
longitudinal series on each side consists anteriorly of an oblique group of fairly long and strong spines;
behind this two or three groups of comparatively long and slender setae are found, followed by a more
medially placed, almost square, area of short spines; behind the last mentioned group, which is only
separated from the corresponding one of the other side by a narrow smooth area, an oblique one covered
with delicate hairs is found. The lamina labialis seems to be represented by a very short transverse

plate; in front of it and the serrula 6-dentata a medial short row of fairly long
setae and a longer curved lateral one of shorter setae are found. Behind the
lamina labialis and between the serrulae is found on each side a short group
of strong spines, almost fused with the corresponding one of the other side, as
well as a more posterior and lateral group. The arrangement of the delicate
hairs behind, as well as upon, the labial lobes consists, as in X ovatus (fig. 14 b)
of a median and, on each side, a lateral group, in addition to more laterally
placed scattered setae.

i$. Size of specimen from Thor St. 214 was 474 mm.; anterior divi-
sion 3-14 mm. ; urosome i-6 mm. Sars' specimens measured 4-5 mm.

The fifth thoracic somite is well marked out, and its lateral corner is
rounded. The comparative length of the abdominal somites and the furcal
rami is 15, 83, 47, 52, 10 and 20.

The antennulae extend somewhat beyond the end of the thora.x, and
are distinctly attenuated towards the end; they are proximally to segment 14
slightly curved, and the proximal portion forms an obtuse angle with the
more attenuated distal portion. The segments 8^9 are completely fused with
segments 10 — 12; the segment 13 is well separated, and the segments 21 — 21
generally so. "^sthetasken" are beyond segments 8 cn^ 9 only observed in seg-
ments 12, 14, 15, 16 and 25. The antennae have comparatively long setae,
and the second outer segment is distinctly restricted in the middle. The manducatory part of the
mandibulae is more soft-skinned than in the female, and has less powerful teeth ; the third basipodite
is much wider than in the female, almost as wide as long, and has the inner setae short and delicate.
The vtaxillulae are more elongated, and their setae are less powerful than in the female; the Li II has
only a single seta, the Basp. Ill has only 4, and the Ri I has 2 for 3. The maxillae are in general
shape like those of the females, but their appendages are less developed. The maxillipcds are as figured
by Sars, but are more slender and delicate.

The natatory legs are scarcely different from those of the female.

The Jifth pair of legs is scarcely different from Sars' figure; the terminal attenuated part of
the right endopodite is articulated, and corresponds to the third segment.

Text-fig. 58.
Scaphocalanns magmis T. Scott,
a— i. Left lateral corner in S
different adult females X 59.
j— k. Same of two young males

(St. V) X 59-

COPEPODA igi

Yq (St. V). Size of male from Thor St. 183 was 3-94 mm.; anterior division 3-04 mm.; urosome
0-90 mm. Another specimen measured 4-12 mm.

The shape of the body is in tlie main Hke that of the adult females, but the articular line be-
tween the head and the first thoracic tergite is fairly distinct; the fifth thoracic somite is well marked in
front with produced pointed lateral corners directed somewhat downwards (text-figs 58 j — k; Pl.VIII fig. 6f).

The antennulae almost reach the end of the body; the other appendages are scarcely different
from those of the adult female; the spinulation of the anterior surface of the natatory legs is well
developed.

The only difference between the sexes is found in the fifth pair of legs, which in the male has
2 fairly elongated basal segments and a two-segmented exopodite in addition to a somewhat shorter
endopodite (PI. VIII fig. 6 g).

Variation. In an adult female from Thor St. 183, which had the lateral corner of the thorax
produced as in text-fig. 58 g, but in no other respects differed from the described specimens, the fifth
pair of legs was distinctly asymmetrical with a rudimentary endopodite (Pl.VIII fig. 6 c); in another
female (Nr. 2) with the same shape of the lateral corner, the pes V was symmetrical and like the right
leg in Nr. i, but with strong inner seta and rudimentary outer one; in a third specimen, like the
others from St. 183 (Nr. 3), a fairly well developed endopodite was found, and two Se were present in
the exopodite; in a fourth specimen from Thor St. 152 (Nr. 4) with the lateral corner like text-fig. 58 b,
the third outer segment has two terminal setae, but no endopodite was found. The pes IV in an ab-
normal specimen is seen in fig. 6 b (PI. VII).

Occurrence. The Ingolf Expedition has not gathered any specimen of this species, probably
because it prefers the deeper strata, at least in the northern regions; by the Thor it has been gathered
at a good many localities. It is rather curious, that the young males of the penultimate stage are much
more common than the young females; of the examined 34 young specimens only 5 were females.

In Denmark Strait:

'9/6 1904 St. 152 65°oo L. N. 28°io L.W. Yt. M. Wire 18 f?, 3 yc? (V).

Yt? 2 yd* (V).

^Ve 1904 St. 154 65°27 L. N. 27°io L.W. Yt? i i^.

^% 1904 St. 150 65°5o L. N. 20°53 L.W. Yt? 12 f? (i sp.), i yS.

South of Iceland the species was taken at 3 stations viz:
Vg 1904 St 285 62°49 ^- N- i8°46 L.W. Yt 500 M. Wire 6 f?, 2 y?, 6 vc?.
"/? 1904 St 183 6i°30 L.N. i7°o8 L.W. Yt 1800 M.Wire 28 f? with rounded lateral corner, 15 f?

with lateral corner more or less produced and 3 i% with Ri pes V, i fc?, 2 y? (V), 11 yc? (V).
=4/5 1904 St 104 62°47 Iv- N. i5°03 L.W. Yt 1500 M.Wire 25 f?, i yS.
In the Iceland— Faeroe channel it was taken at 4 stations viz:

29/8 1905 St 165 60^00 L.N. io°35 L.W. Yt 1000 M.Wire i f?.
Vg 1905 St 167 57°47 L.N. ii°33 L.W. Yt 1500 M.Wire 27 f?, i y?, 2 yd'.
9/5 1904 St 70 63^32 L.N. 6°20 L.W. Yt 100 M.Wire i f?.
^3/7 1905 St 124 6i°04 L.N. 4°33 L.W. Yt 1000 M.Wire 2 f?.

J02 COPEPODA

North-east of Iceland:

^7; 1904 St. 214 67°i9 L. N. i7°55 L. W. Yt. 800 M. Wire 19 f?, i fc?, i yc? (V).
Outside the Ingolf area the species was captured:

'5/6 1905 St. 82 si^'oo h. N. ii°43 L.W. Yt. 800 M. Wire i f?, i yc? (Vi.

Yt. 1200 M.Wire 4!?, 4 yd" (V).

% 1905 St. 72 57°47 L. N. ii°33 L. W. Yt. 1500 M.Wire 35 f?, i fd", 2 y?, 10 y5.

2% 1905 St. 88 48=09 Iv. N. 8°30 L. W. Yt. 300 M.Wire i f?.

Distribution. This species seems to have a world-wide distribution; it has been found, though
rather scarce, generally in considerable depths in the Antarctic seas (65° S. 85° E.), in the Atlantic, south
as well as north, even at the Equator (c. 30° L. W.), in the Arctic seas, in the Malay Archipelago, in the
Gulf of California between 50 and 300 fathoms (Esterly 1912, p. 321) and in the Pacific (35° L. N. 125°
L. W. o— 300 m.). According to Farran (p. 52) it is "a very common and noticeable species in deep
water" off the west coast of Ireland, "it occurred on every station and in almost every tow-netting be-
tween 280 and 1 150 fathoms". The species was sometimes found in the Norwegian Sea between 200
and 1000 metres as well as in the deep Norwegian fjords. By the Due d'Or leans it was taken at eleven
stations (in about 15 samples) in the ocean east of Greenland between about 200 and 1800 metres; it
is rather curious that it was never found farther east than 9°oo L. W. at 75°55 L. N. ; it was found
near the coast of Greenland and as far north as 78°i3 L. N. It was found as far south as 71=22 L. N.
(i8°58 L. W.); only in a single sample St. 43 '/b 1905 78=13 L. N. i6°3i between 310—475 meters was it
found fairly common, males as well as females. By the Nanseu's Expedition it was found fairly,
abundant, sometimes up to the very surface of the sea as far north as 84° L. N. between 134 and 76
Long. E. These different facts indicate, as pointed out by Sars, that this form has its main area of
distribution in the Polar basin, though it is found in small numbers in the deeper layers of the dif-
ferent seas.

Remarks. As the variations in the lateral corners, as well as in the fifth pair of legs in the
females, are rather common, I did not find any reason to establish a new species for the three men-
tioned specimens with a well developed endopodite. The features which distinguish ni)- specimens
from Giesbrecht's Sc. cristata are enumerated above, and are too unimportant for establishing two
species. Wolfen den's spechuens from the Atlantic measured 37, and those from the Antarctic seas
4*25 mm., but he could not find any other characters, except in the comparative length of the spines
of the fifth pair of legs, which, as shown above, are very variable.

60. Scaphocalanus brevicornis G. O. Sars.
(PI. VII figs 7 a— b; textfigs 59 a— b).

1900. Scolecithrix brevicornis n. sp. G. O. Sars, pp. 46—47, pi. X.
1902? — _ G. O. Sars. Th. Scott, p 452, pi.

XXV figs 1-2.
1903. Amallophora brevicornis G. O. Sars. G O. Sars, pp. 53—54,

pi. XXXVI.
1904? — _ _ Wolfenden, p. 137.

1907. Amallophora brevicornis G. O. Sars. Daiiias & Koefoed,

p. 410.

1908. Scolecithrix graciHpes n. sp. Farran, pp. 52—53, pi. VI

figs 1-4.
1908. — brevicornis G.O. Sars. v. Bremen, p. 78, fig. 90.

1913. Amallophora brevicornis G. O. Sars. Stephensen, p. 314.

COPEPODA

193

Description, f ?. Size of specimens from Ingolf St. 105 was 2-23 mm; anterior division i-66 mm.;
urosome 057 mm. Sars' specimen measured scarcely 2 mm.; Farran's 2'3 — 2-5 mm.

The shape of the body is scarcely different from Sars' figures; the appendages, as far as they
were examined in the single mutilated specimen, were scarceh- different; posteriorly, near the end of the
second outer segment of tlie first pair of legs, a transverse row of short spines was found. The fijtii
pair of legs has on the left side the Se standing opposite the Si, as in Sar.s' figure, but on the right
side it stands somewhat more distally.

fc?. Size of specimen from vSt. 82 Thor was 2-5 mm.; anterior division 1-65 mm.; urosome 0-85 mm.
A male from St. 183 measured 3-3 mm.

The shape of the body is rather slender, very much like that of S. viagnus. The distinction
between the head and first tergite is indicated dorsally, and the fifth thoracic tergite, which is rounded,
is well marked out. The rostruiii consists of a basal bifurcate part, which
is prolonged into a thin rather stiff filament on each side; the outline
is, above the rostrum, at least in the single, somewhat mutilated specimen,
somewhat concave. The abdomen (fig. 7 aj is distinctly half as long as the
anterior division, and the comparative length of the somites is 7, 43, 27,
30, 4, and 10 for the furca, which is about 1-3 as long as wide.

The antenmilac, which were broken, have the proximal segments
like those of A^. iiiagiiiis. The <nitrnnac are scarcely different from those of
the female. The manducator\- part of the mandibulac is rather slender; the
third basipodite is very short and robust; it possesses, somewhat beyond
the middle, a single short hair and, more terminally, at least one quite rudi-
mentary one. The ii/axill/ilac are well developed and in most respects like
those of the female. The long well developed Li I has 10 short setae at
least, the Li II has one, the Li III has 3 at least, and the third basipodite
has 5; the Ri I has 2, and the Ri III ~ II liave 5 setae; the exopodite
has 7 well developed setae. The maxillae and luaxillipeds are in most
respects like those of the preceding species.

The natatory legs were scarcely different from those of the female;
on the posterior surface of the third outer segment in the first pair of legs no spines were observed.
The fifth pair of legs (fig. 7b and text-fig. 59b) is in the main Hke those of the preceding species,
but differs, however, in a few respects. The inner terminal process of the first outer segment of the
right foot is somewhat pointed, not rounded; the right endopodite has the two first segments some-
what convex with a small inner terminal process, which was not observed in the bigger specimen; the
terminal segment is better articulated. The left right leg is scarcely different from that of the preceding
.species except in minor details, as seen when comparing figures (text-fig. 59 b); the left Re III has 3
fairly long setae.

Occurrence. The Ingolf Expedition has gathered a single mutilated female with closing net
700 fathoms '■/- 1896 St. 105 65°34 L. N. 7°3i L. W.

The S/S Thor has gathered a single male:

Tile Ingolf-Expedition. ill. .\. ^

Text-fig. 59. Scaphocnlanus bre-

vicornis G. O. Sars. f d'-
a. Pes V dext X c. 150. b. Pes
\' in situ from the left; termi-
nal segments >' c. 250.

IQ. COPEPODA

"/y 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire.
'Ve 1905 St. 82 5i°oo L. N. ii°43 L. W. Yt. 1200 M. Wire.

Distribution. This species has been found at a single station in the Polar basin at about
84° h. N. and 90° L. E. In the sea between Spitzbergen and Greenland the Due d'Or leans has between
"/j, and 5/3 gathered it at 4 station.s, and sometimes in considerable numbers, males as well as
young ones, f. inst. at St. 43 78°i3 L. N. i6°3i L. W. 310—475 meters depth; the three other localities
were at 79°39 L. N. 2°4o L. E. 1200— 1800 Meters depth, at 78°o5 L. N. 5°2i L. W. 500—1350 M. deptli,
and 7i°22 L. N. i8°58 L. W. It has once been recorded from the Norwegian Sea in a depth of about
400 M., and from the west coast of Ireland at a deptli lying between 280 and 680 fathoms, and always
rather scarce.

Remarks. Though the males and the female were found at widely separated localities, I am
fairly convinced that they belong to the same species, and without doubt to S'. brcvicornis. As the male
described by Scott is only 1-5 mm., and as the fifth pair of legs seems to differ in several respects,
I am not convinced that it ought to be referred to this species.

I am fairly convinced that Farran's species S. gracilipts^ which was established with due
reservation especially on account of "the more distal position occupied b\- the outer-edge tooth of the
second joint of the fifth foot," is identical with thi.s. Farran has (p. 53) found a rudimentary endopodite,
like that observed in specimens of i'. magnus (cf. p. 191) in a specimen of his Scolecithrix gracilipes as
well as of his 6". valida^ which he regards as an anormality. In this, as well as in his opinion of
Giesbrecht's genus Racovttzanus, I agree with him (cf. Wolfenden 1911 p. 259).

61. Scaphocalanus obtusifrons G. O. Sars.
(PI. VII figs 9a — d; PI. VIII figs 8 a— e; text-figs 60a— c and 61 a — d).

1905. Amallophora obtusifrons n. sp. G. O. Sars, p. 22. 190S. Scolecithrix obtusifrons G. O. Sars. v. Bremen, p. 25, fig. 87.

1905. Scolecithrix eniarginata n. sp Farran, pp. 36— 37, pi. VII 1909. Scolecithricella obtusifrons G. O. Sars. A.Scott, p. 92, pi.

figs 6-17. ; XXXI figs 1—9.

1906. Amallophora obtusifrons G. O. Sars. Pearson, p. 17. 191 1? Scolecithrix requalis n. sp. Wolfenden, pp. 255— 256, text-
1906? Scolecithrix inornata n. sp. Esterly, p. 67, pis 9, 1 1 and 13. fig. 33.
1908. Scolecithrix obtusifrons G. O. Sars. Farran, p. 54.

Description, f^. Size of specimen from Thor St. 72 was 4-4 mm.; anterior division 3*55 ; uro-
some 0-85 mm. Sars' .specimens measured 5-6 mm., Farran's 4-3 mm. and Scott's 45 mm.

The shape of the body etc. is scarcely different from Farran's description; each filament of
the rostrum is as stated by Sars and Scott terminally bifurcate (text-fig. 59a). The genital somite
is sHghtly produced below, and has a well developed curved receptaculum (PI. VIII fig. 8 a).

The antcnmiles^ which extend a little beyond the end of the furca, are in measurement almost
exactly like Farran's figures; the segments 24 and 25 are fairly well separated, the proximal seta is
wanting in segni. 10 as well as in 17, and the Sp. of segment 24, which is placed near the tip, extends only
slightly beyond the end of segment 25. The exopodite is distinctly longer than the endopodite of the
antennae, and this has 7 setae in the Li of the second segment and 5 setae in the Le. The Diai/di-
hilae are scarcely different from those of S. iiiagnus. The iiinxilhilac are like Farran's figure, with 8
setae in the exopodite and 7 long setae and a shorter more delicate one in Le. The maxillar have the

COPEPODA iQc

exterior margin distinctly produced, and have, in addition to powerful vermiform sensory appendages,
at least 5 amalliform or brush-shaped ones. The maxillipeds are like those of 5. magnus, and have,
in contrast to Farran's, a sensory seta in the middle of the second basipodite.

'Y\i^ first pair of legs has, as stated by Far ran (fig. 14 PI. VII), a well developed Se in Re I,
attaining the middle of Re II. The second pair of legs is in main features like Farran's fig. 15 (of. text-
fig. 60 b), but the outer marginal tooth of the second basipodite is well developed, and the inner margin
is near the tip produced into a short curved tooth; the arrangement of the spines on the posterior surface
differs only in minor details, f. inst. by the presence of spines in Re I, but in addition to the spines
areas of short teeth were found on the posterior surface of the exopodite; the anterior surface seems
to be smooth; the first inner segment has a well developed Se; the St of the third outer segment has
about 70 partly fused teeth (fig. 9 a) without the characteristic basal fenestra. Glandular pores seem
to be present in Re II and III. The third pair of legs has the inner margin of the second basipodite,
a little proximally to the Si, produced into a longer or shorter, generally broken, styliform process,
corresponding to that of the second pair of legs; this process is beset inwards as well as terminally by
the most distally placed marginal bristles, and in this way
forms a prolongation of the inner margin proper; the
third basipodite is anteriorly and terminally produced into
a distinct slender spine medial to the insertion of the endo-
podite (text-fig. 60 c), like that of Scottocalanus. On the anterior
surface of the third feet, except in the third outer segments,
a delicate spinulation is foimd; the spinulation of the

posterior surface is like Farran's description, but a basal Text-fig. 60. ScaphocaianusobtusifronsQ..o.^^r','Lri.

a. Head X 33- b. Pes II sin in ant. view X 58.
group is found in the third outer segment. The fourth c. Pes IV sin in ant. \aew x 58.

pair of legs (text-fig. 60 c) has the second basipodite very

clumsy without marginal bristles, and is suddenly restricted near the tip; on the posterior surface trans-
versely placed .short spines were observed in Ri II, and in a less' degree in Ri III, but the anterior
surface is covered all over with areas of more or less delicate teeth; the serrations of the terminal
setae are more or less fused in the middle; a glandular pore is observed not only in Re II and III,
but in Re I as well. The fiftii pair of legs has the exopodite divided into a short basal and a longer,
somewhat enlarged outer segment, possessing a shorter terminal and a longer more proximal seta.

The anterior portion of the labrnvi proper is distinctly more produced in front than seen in
fig. 8 a of 5. i/iagiiiis; the arrangement of the setae is, as seen in fig. 9 b, rather characteristic; the an-
terior curved group of long delicate setae is posteriorly on each side divided into an outer and inner
portion; in the middle an anteriorly convex row is found; for further details I refer to the figure.
The oral surface of the labrum (PL VII fig. 9 e) .shows a rather characteristic structure, bearing most
resemblance to that oi Scottocalanus; the first oblique group of the longitudinal series is smaller than
in .S'. magnus, and it is followed by two or three more or less fused groups of fairly long setae, between
which the transverse median rows are placed, behind the mentioned groups an oblique one of more
slender hairs, corresponding to the square one of ^: viagnus is found. Laterally, in front, two groups of
delicate hairs are found. No distinct lamina Inbialis was observed; in front of the serrula 6-dentata an

25*

196

COPEPODA

inner and an outer longitudinal series were found (PI. VII fig. gd); the arrangement of hairs Ijetween
and behind the serrulae was not studied in details. In the middle, between the labial lobes, a large
median o-roup of setae was found, which on each lobe is continued into two lateral series placed
closely to each other; more laterally, well separated from this system, a lateral row of shorter setae,
starting from a basal group, was observed.

The intestinal tract is anteriorly produced into a rather slender rostral coecal sac; posteriorly
the wide stomach is attenuated, and is, somewhat in front of the abdomen, continued through a slight
curvature into the straight intestine proper.

f<^. Size of specimen from Thor St. 180 was 3-84 mm.; anterior division 2-65; urosome 1-19 mm.

The body is somewhat more slender than in the female, with rounded lateral corners of the

well marked short fifth somite; the rostral filaments are scarcely different. The /^wi-WA/r is almost half

as long as the anterior division, and the comparative
length of its .somites is 23, 40, 34, 44 and 4 (PI. VIII
fig. Be).

The aiifeniiu/ac scarcely extend to the end of
the furca; the number of free segments is scarcely
different from that found in S. ii/agiiiis\ but the seg-
ments 13 and 15 are partly fused with the preceding-
ones, as the articular line is wanting behind; the
measurements and the appendages are ver\' much
like those of S. globiceps. The antciinoc and iiiondi-
biilac are scarcely different from those of X magims.
The Diaxillulae are fairly well developed; the Le
possesses 9 setae; the Li I has at least 8 rather
delicate setae, the Li II has 2 setae and the Li III has 4 setae; the third basipodite lias 4 setae; and
the Ri 2 + 5 setae; the exopodite has as in the female 8 setae. The maxillae are fairly developed,
with 4 setae in each of the four proximal lobes; the lobe V has one spine somewhat stronger than
the corresponding one of the lobe IV; the endopodite has 6 soft sensory setae, but not amalliform ones,
the maxillipcds are like those of the male of S. viagniis^ but no setae were observed in the middle of
the second basipodite.

The natatory legs show in all features of interest complete similarity to those of the female.
T\ie. Ji/th pair of legs is verj' characteristic, as seen in text-fig. 61 a; on the right side (PI. VIII
fig. 8 c) we have a long and slender first basal segment, followed by a well enlarged second segment.
The right endopodite (text-fig. 61 b) is. rather short, somewhat clavate, and has a slender, delicate seta
almost half as long as the segment; the right exopodite consists of three long slender one.s, of which the
first is much the longer and thicker, while the third, somewhat plate-shaped one, is the shortest and
most slender (text-fig. 61 c). The two basal segments on the left side are, like those of S. magnits, long
and slender; the left exopodite has 3 segments (text-fig. 61 d), of which the third one, which is much
the shortest, is distinctly attenuated, with a terminal seta; the left endopodite is long and slender
and extends distinctly beyond the end of the exopodite.

Text-fig. 61. Scaphocalamis obhisifrons G. O. Sars fd"-
Pes V X 58. b. Pes V dext. Ri X 150. c. Pes V
dext. Re III X 150- d. Pes V sin. Ri X i5o.

COPEPOUA

197

Yq (St. V). Size of specimen (male as well as female) from Thor St 152 was 3-65 mm.; anterior
division 2'96mm. ; urosome 0-69 mm.

The abdomen has four somites, but in other respects scarcely any difference was observed from
the adult females, except by the better developed articulation of the exopodite of the fifth pair of legs
in the females (fig. 8e). The fifth pair of legs of the males is clumsy, and most similar to that of
Scottocalaims, but has the setae better developed (fig. 8 d PI. VIII).

Occurrence. The Ingolf Expedition has not gathered this species, but the vS/S Thor has brought
it home from several localities.

In Denmark Strait it was found :

-"/e 1904 St. 154 65°27 L. N. 27°io L. W. 3 f?.

■9/6 1904 St. 152 65°oo L. N. 28°io L. W. Yt. 1000 M. Wire 12 f?, i y? (V), 3 y^ IV).

In the Atlantic, south of Iceland:

'/g 1904 St. 285 62°49 L. N. i8°46 L. W. Yt. 500 M. Wire i y? (V).

>°/7 1904 St. 180 6i°34 L. N. i9°o5 L. W. Yt. 1800 M. Wire i f?, i fd".

'V7 1904 St. 183 6i°3o L. N. i7°o8 L. W. Yt. 1800 M.Wire 7 f?, i fc?, 2 y? (V), 2 yc? (V).

24/5 1904 St. 104 62°47 L. N. i5°03 L. W. Yt. 1500 M.Wire 10 f?, i yc? (V).

In the Iceland-Faeroe channel :

29/8 1904 St. 165 6o°oo L. N. io°35 L. W\ Yt. 1000 M.Wire i f$.

"/5 1904 St. 99 6i°o5 L.N. 9°35 L. W. Yt. 1700 M.Wire 2 f?, 6 fd".

Vq 1905 St. 167 57°46 L. N. 9°55 L. W. Yt. 1500 M.Wire 151?, i y? (V), i yc? (V).

8/6 1905 St. 72 57°47 L.N. ii°33 L. W. Yt. 1500 M.Wire 14 f?, 5 y,? (V).

Distribution. "This species is a noticeable feature of the deep water plankton off the west coast
of Ireland" "at depths of from 330 to 1150 fathoms" (Farran); it has been taken by the Monaco Ex-
pedition as well as in the Malay Archipelago.

Remarks. That this species is identical with Farran's Sc. emarginata is scarcely doubtful; Far-
ran's specimens were identified by Sars with his A. obtusifrons, which is, however, distinctly bigger
and has the fifth feet somewhat different "muni en dedans d'une epine assez forte et allongee, et en
autre de 2 petits denticnles, I'un apical, I'autre sortant du bord exterieur". It differs from Scott's de-
scription by the wanting delicate spinulation of the posterior surface of the fourth exopodite.

This species is nearly related to, if not identical with, Wolf en den's 5. aeqitalis from the South
Atlantic (191 1, p. 255), as well as with S. inoriiafa Esterly (1906, p. 67), but the descriptions are too insuf-
ficient for solving the question.

The species is characterised by the robust shape of the body and the antennnlae, which are longer
than the body, without Spr. in segment 17, and without setae in segment 10. The Se Re I pes I is
comparatively short, and only attains the middle of the following segment, while the Se Ri I pes II is
long and pointed. The St. Re III pes II has about 70 partly fused teeth. The inner terminal seta of
the anterior surface of Basp. Ill— IV is well developed, long and slender. The second basipodite of the
third pair of legs has a distinct lateral tooth, but no spinous lamina.

igS

COPEPODA

52. Scaphocalanus validus Farran.
(PI. VII figs II a— b; text-figs 62 a— f.)

1908. Scolecithrix valida n. sp. Farran, pp. 55-57. pi. V figs 14—15, pi. VI fig. 7.

Description. f$. Size of specimen from Thor St 183 was 395 mm.; anterior division 31 mm.;
urosome 0-85 mm. Farran's specimens measured 3-8 — 3-95 mm.

The body is more slender, and the head less suddenly raised in lateral view than in S. obhisi-
frons, but more distinctly so than in .5". globiccps (text-figs 62 a — b). The rostrum is most like that of
the former species, with the basal part less enlarged and with fairly long, apparently undivided, filaments.
The lateral corners are slightly produced and rounded (text-fig. 62 c). The genital somite is better produced
below, and its receptaculum seminis appears more slender than in the preceding species ; the comparative

length between the abdominal somites and the furcal rami is
45, 28, 25, 9 and 17; the furcal rami are 1-5 as long as wide;
along the hinder border of somites II — 1\' a marginal seam
with delicate serrations is observed.

The ant£7inulai' do not reach the end of the furca; the
segments 24 — 25 are fairly well separated ; "^sthetasken" are
found in segments 80^9, 12, 14 and 19; the segment 10 has a
distinct seta, and a proximal seta is found in segments 12 — 14
18, and sometimes in segment 15, but never in segment 17;
the Sp. of segment 24 is somewhat longer than segment 25.
The segment 19 is distinctly 12 as long as segments 8 "^9

Text-fig. 62. Scaphocalamis valiiius Farr. fO. , i-i ^ \ j_ iii-L ,. /■ ■

and 15, which are of almost equal length; segment 16 is 12
a. Head X 33- b. Rostruui from the right X 59.

c. Genital somite X 33- d. Pes II sin. in anterior as long as 15. The third basipodite of the iitandibulae seems
view X59. e. Pes III sin. X 59- f- SL pes II ^^ j^^^.^ ^^^1^. ^ ^^^^^ uiediallv ; in Other respects the mandi-
sin. X 150- ■ ■

bulae as well as the antennae are like those of the preceding

species. The maxilhilae have 7 — 2 setae in the Le, 10 — 2 in the Li I, 2 in Li II, 4 in Li III and 5

in the third basipodite; the Ri I has 3 setae, the Ri II ^ III 5 and the Re has 9 setae. The niaxilUw

and maxillipeds are scarcely different from Farran's description.

The first pair of legs has the Se Re I extending to the base of Se Re II; in the outer edge of

the Re III, proximally to the middle, a distinct glandular pore is found, better developed than in other

species. The second pair of legs (text-fig. 62 d| is like Farran's fig. 16 PI. V; the Se of Ri I is

rather short and clumsy, and the St. of Re III has about 35 serrations, some of which are fused at

their base (text-fig. 62 fi; the anterior surface of the appendage is minutely granular, and the posterior

one has, in addition to the usual spines, areas of smaller teeth. No glandular pores were observed.

The tfiird pair of legs (text-fig. 62 e) has no distinct st^liform process at the inner margin of the second

basipodite, and the slender terminal tooth of the anterior surface of the third basipodite medial to

the insertion of the endopodite is very short and clums}- ; the posterior surface of the third basipodite

has a number of short spines in contrast to that of the second foot, which is smooth; in other respects

this pair is like that of the preceding species. The /o/tri/i pair of legs has a long and slender second

COPEPODA igg

basipodite without marginal setae. The fifth pair of legs is like Farran's figure, with a long and
strong inner seta, a rather short terminal seta, and a very delicate outer one; all segments are fused,
but the two basal ones are indicated.

The anterior portion of the labritm is, in lateral \iew, less prominent than in preceding species;
in front of the labrum proper behind the transverse line, which limits the antennal somite, a tuft
of long setae is found. The arrangement of setae on the anterior surface of the labniin iPl. VII
fig. II ai is, as seen by comparing figures (cf. gb), like that of S. obfnsifroiix^ but the lateral posterior
group is better developed, and the central group has only a few setae. The oral surface of the labrum
is most like that of .S". globicips (PL VII fig. loa), but the granular area in front has much smaller
granules, and it is much smaller. The structure of the lamina labialis etc. is completely like that
of 5". globiceps.

Yd' (St. V). Size of young male from Thor St. 183 was 3-25 mm.; anterior division 2'5i mm.;
urosonie 074 mm.

The only difference, except the usual one in the shape af the abdomen, is found in the more
obtuse inner tooth of the third basipodite of the fourth foot. The segment 10 of the aiitenniilae has
a seta, but the segment 17 has no proximal seta. The fifth pair of legs is more .slender than in ^9. nb-
tusifrons, but is alike in other respects.

Occurrence etc. The S/S Thor has gathered the species at a single station viz: ''/y 1904 St. 183
6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 5 i% 2 yd* (V). It has only been recorded once by Farran,
who has examined six specimens, taken at a depth of 700 fathoms off the west coast of Ireland. As to
the differences from the related species I refer to S. globiceps. The species is characterized by anten-
nulae about as long as the body, with a seta in segment 17. The Se of Re I pes I is fairh' long and
slender, and the Se Ri I pes II is rather short and obtuse. The St. of Re III pes II has 35 partly
fu,sed teeth. The inner terminal seta of the anterior surface of Basp. Ill pes III— IV is only poorly
developed. The second basipodite of the third pair of legs has no spinous lamina.

63. Scaphocalanus globiceps Farran.
(PI. VII figs 10 a— b; fig. 11 b; PL VIII figs ga-c; text-figs 63 a— b.)

1905. ? Scolecitbricella gracilis n. sp. G. O. Sars, p. 2.

190S. Scolecithrix globiceps n. sp. Farran, pp. 54— 55. P'- ^' f'gs 8 — 13, pi VI fig. 8.

Description, f?. Size of specimen from Thor St. 183 was 4-48 mm.; anterior division 3-38 mm.;
urosome i-io mm. Farran's specimens measured 4-3 — 4-5 mm.

The body is more slender, and the abdomen comparatively longer than in the preceding species;
the fifth thoracic tergite is somewhat produced, but rounded. The rostral branches, arising from a short
basal part, are almost straight, stiff and fairly long, apparently longer than the pointed slender fila-
ments (text-fig. 63 a). The genital somite is onh- slightly produced below, and has an elongate, distally
not enlarged, receptaculum seminis (text-fig. 63 b). The comparative length between the abdominal
somites is 53, 35, 30 and 10. The serration along the posterior margin of the somites is distmct, at
least dorsalh-. The anfriiuiilar extend to the end of the furca; the appendages differ from those of

200 COPEPODA

S.vah'dtis by the presence of a proximal seta in segment 17; the measurement is like that of the pre-
ceding species, but for the segments 8'>3 9 and 19 which are of equal length. The manducatory part
has 3 setae in the third basipodite, but in other respects the /i/ai/dibulae as well as the antennae and
niaxillulae are scarcely different from those of the preceding species. The maxillae and inaxillipeds
show, as pointed out by Far ran, a few rather unimportant differences.

The first pair of legs is scarcely different from Farran's description, and the second pair is
very similar as well; the Se of the first outer segment is short and i-obust; the anterior surface of the
third basipodite as well as of the two branches is covered all over with areas of small spinules; on
the posterior surface the number of teeth is like F"arran's fig., but a patch of distinct teeth is found
near the apex of the third basipodite. The terminal seta is adorned with about 20, well separated, coarse
serrations. A glandular pore was observed at the base of Se 3 Re III. The third pair of legs has, along
the exterior border of the second basipodite, a low lamina, which, in the middle, has a row of 15— 20
fairly long spines not observed in the other species, and most distinct when
observed in situ; the spinulation, especially of the anterior surface, is better marked
than in the second pair; on the posterior surface of the third basipodite it is
scarceh' better developed. The inner tooth of the anterior surface of the third
basipodite is short and rounded. The second basipodite of the foiirtli pair of legs
is comparatively less slender tlian in tlie preceding species; the inner tooth of
the third basipodite is just indicated; the spinulation of the anterior surface of
the basipodites as well as of the first outer and inner segments is well developed ;
the distal segments of the exopodites as well as the endopodites are wanting,
fext-fig. 63. 'pjjp fifth pair of legs is scarcely different from Farran's description.

Scaphocalanus glohiceps

Farran. f9. The anterior surface of the labrmn seems, in most respects, to be like

a. Head X 33 ^- Ge- jj^^j gf _(,• obtusifrons (PL VII fig. 9 b), but the oral surface differs distinctly from
nital .somite X 33-

that species (PI. VII fig. 10 a, cf. fig. 9 c); the most characteristic feature is found

in the distinct spinulation behind the marginal setae around the two first median circular spots and

as far lateral as the first well developed group of short spines; as to the other features I refer to the

figure. The laviina labialis is scarcely indicated; in front of it, the usual inner and outer row is seen

(fig. 10 b); posteriorly, between the serrula 6-dentata, a median group of short spines is found, as well

as a paired one more behind. In the middle, behind the labial lobe, two more or less separated groups

of shorter and longer hairs are found, laterally continued into a wide oblique row along the inner

margin of the lobe. More laterally the lobe possesses an angle-shaped series of densely placed hairs

as well as a basal group without direct connection.

fc?. Size of specimen from Thor St. 180 was 4-44 mm. ; anterior division 2-99; urosome 1-45 mm.

The body is somewhat more slender than in the female, and the abdomen is about half as long
as the anterior division; the comparative length of the abdominal somites is 15, 45, 40, 45, 4 and 14;
the furcal rami are about 1.3 as long as wide. The antcnmilac reach somewhat be)'ond the end of the
third abdominal somite; the segment 13 is fairly well separated from 12, and segment 14 from 15, but
segments 20 and 21 are completely fused on the right side, but well separated on the left; beyond
segments 8<^9 2 setae were found only in segments 12 and 14. vSegmeut 22 is 1-4 shorter than seg-

COPEPODA

20I

iiient 19. The mouth-appendages are comparatively slightly transformed; the third basipodite of the
iiiandibulae has, in addition to a fairly long Se i and a quite rudimentary Si 2, a small rounded process.
The iiiaxilhdae and the niaxillnc are scarcel\- less developed than in the female; the iiiaxillipcds are
comparatively less slender, but tlie amalliform seta of the second basipodite is well developed as in
the female. The natatory legs are practically like those of the female, but the spinulation, especially,
of the anterior surface is less developed, and the medial terminal tooth of the anterior surface of the
fourth pair of legs is better developed; the terminal seta of Re III pes II has about 60 serrations. Along
the outer margin of the second basipodite of the third pair of legs, a lamina with a row of short spines
is found.

T\\& Ji/th pair of legs, which in natural position is seen to extend a little beyond the end of
the abdomen is very much like that of S. obtusifrojis. The right endopodite (PL VIII fig. 9 b) is rather
short, distally somewhat triangularly produced, and rather suddenly attenuated to a fairly long spine.
The right basipodite (fig. 9 a) is, outwards, produced into a long process which is fused with the first
outer segment; a terminal process of somewhat triangular shape, as in S. i/iagiiHs, as well as a median
one is observed; the second outer segment is rather short and somewhat curved, and the third one is
short, flat, slightly curved and somewhat attenuated (fig. 9 a). The basipodites of the left foot are long
and slender; the comparatively short and slender endopodite is slightly curved, and indistinctly divided
into two proximal segments of about equal length as well as a short third segment with a fairly
slender terminal seta beyond a rounded process. The left exopodite is comparatively long and clumsy;
its first segment is the longer, and has two triangular processes, while the third one is the shortest,
and hairy (PL VII fig. lib).

Yq (St. V). Size of female from Thor St. 183 was 3-49 mm.; anterior division 271; urosome
078 mm.

The shape of the body shows the usual difference from that of the adult female; the distal
segments of the antennulae are comparatively longer; the segment 19 is i-i as long as segments So-* 9;
the fifth jDair of legs is somewhat smaller, but in other respects scarcely different.

Occurrence. The S/S Thor has taken this species at three stations in deep water viz:

1/9 1904 St. 285 62°49 L.N. i8°46 L. W. Yt. 500? M. Wire i f?.
10/7 1904 St. 180 6i°34 Iv. N. 19^05 L. W. Yt. 1800 M. Wire 2f? + ifd'-
'V7 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 2 f?, 3 f^, 2 y? (V).

Distribution. The species has only been recorded twice by Farran off the we.st coast of Ire-
land at 1000 and at 700 fathoms.

Remarks. This species is certainly identical with Farran's species, as they do not differ in any
features of interest. Though, as far as the description goes, it agrees completely with Sars' ScotcciY/in-
cella gracitis, especially in the structure of the fourth pair of legs, I prefer to refer it to Farran's
species, as it is well distinguished from Scolecitricella according to Sars' own definition.

The described male, which is well distinguished from that of .5". obtusifrons by its long and more
slender fifth foot, I have, on full consideration, referred to this species rather than to S. validns with

The Ingolf-Expedition. III. .\.

202 COPEPODA

which it agrees in a few features, on account of its size and the spinous lamina along the outer margin
of the second basipodite of the third foot.

Scaphocalanus globiceps, obtusifrons, validiis and robnstus seem to be nearly related, and are, without
detailed investigation rather difficult to distinguish from each other. In contrast to Scott, who refers
them to Scolecithricella, I follow vS a r s, and regard them as more nearly related to Scaphocalanus niag-
nus, with which they agree by the number of segments in the antennulae, by the appendages of the
maxillae, and b\' the structure of the fifth foot in the male. About the differences between S. robiisfiis
and globiceps I refer to the former species. The female of S. globiceps is characterised by slender shape
comparatively short antennulae, which have a single setae in segment lo and a vSpr. in segment 17.
Se Re I pes I is long and slender, and Se Ri I pes II is short and clumsy. St. Re III pes II has
about 20 well separated teeth. The inner terminal seta of the anterior surface of Basp. Ill pes III — \\
is only poorly developed. The second basipodite of the third pair of legs has, laterally, a spinous lamina.

64. Scaphocalanus robustus Th. Scott.
(PL VII figs 12 a— c; text-figs 64 a— c).

1S94. Ainallophoni roljusta n. sp. Tli. Scott, pp 56 — 57, pi IV 1H96. Scolecilhrix robusta Th. Scott. Giesbrecht& Schmeil, p. 47.

figs 24 — 26. 1908. — — — Farraii, p. 57, pi. VI fig. 3.

Description. f$. Size of specimen from Thor St. 167 was 278 mm.; anterior division 212 mm.;
urosome o-66 mm. Scott's specimen measured 3 mm. and Farran's 2-65 — 3-1 mm.

The rostrum has rather short filaments (text-fig. 64 a). The head is distinct!) raised, and the
body is rather robust; the first thoracic somite is fiised with the head, and the fourth and fifth thoracic
somites with each other; the lateral corners are slightly produced and rounded. The genital somite
is onh- slightly produced below; the receptaculum seminis i.*; elongated and slender, but rather short
(text-fig. 64 b). The comparative length of the abdominal somites and the furcal branches is 33, 20, 18
10 and 14; the genital somite is almost as wide and deep as long, and the furcal rami are a little longer
than wide. The serration along the hinder margin of somites 2 — 4 is well developed.

The antennulae extend to the end of the genital somite; the limitation between segments 24
and 25 is rather indistinct; the appendages are like those of S. globiceps, with a single seta in segment
10, and 2 in segment 17. The measurements are similar to those of the preceding species; the segments
19 and 16 are almost of equal length, and 1-3 as long as segments 8^9, which are, again, a little shorter
than segment 15. The anfennae, mandibulae, niaxilliclae and iiiaxillipeds are like those found in S.
globiceps. The maxillae possess 4 amalliform and 4 vermiform sensory appendages.

When the natatory legs sitting on the animal are examined from the side, a curious difference
is found between the 3 first pairs and the fourth pair of legs in the basipodites as in related species;
the posterior surface of the three first pairs is seen to be excavated, while that of the fourth pair
appears cylindric, and in lateral view is almost twice as deep as that of the third foot. T\\& first foot
is very much like that of S. globiceps, but the Se Re I scarceh- extends to the end of Re II (text-fig.
64 c). The second foot has the outer-edge spine of the first outer segment long and sickle-shaped, and
the outer-edge spine of the first inner segment short and rounded; the St has 30 short, well separated

COPEPODA

203

teeth; the armature of the anterior and posterior surface is scarceh- different from that of S. globiceps.
The third pair of legs is like those of the preceding species, but the outer-edge spinous lamina of the
second basipodite is wanting, and the posterior surface of the third basipodite has a patch of strong
spines, wanting in the second pair. The four ffi pair of legs is distinctly granular on the anterior sur-
face, but has fairly long spines in a longitudinal area on the two inner segments in addition to the
granulation; on the posterior surface of the two distal outer segments as well as on the distal inner one
a few short spines are observed; on the posterior surface of the second inner segment a transverse
row of 8 long spines is found. The /^//'// /r^'^*/ agrees fairly well with Scott's and Farran's description,
but the articulation is very indistinct.

The labrniii is comparatively slightly produced in front (PI. VII fig. 12 a). The arrangement of
setae on the anterior surface is rather characteristic; in front a median group of fairly long bristles,
3 — 4 deep continued into a lateral group of a number of shorter hairs, extending laterally to in front of
a posterior lateral group of densel)- placed hairs. In the middle, later-
ally partlv fused with mentioned anterior group, a transverse series
of comparatively few short setae. Add to this a marginal group of nu-
merous bristles.

The oral surface of the lahruvi (PI. VII fig. 12 b) shows some
similarity to .S". validris^ and in a less degree to S. globiceps; the granular
area around the first median circular spot is only small; the lateral
marginal and the first lateral group form a fairly long oblique group,
medially consisting of granules, and converging towards the second
median circular spot; the following lateral groups are in the main like
the structures in the preceding species. The arrangement of setae
around the "lamina labialis" . and upon the labial lobes, is very much
like that of S. globiceps.

Variation. In the first right foot in one of the specimens a median outer-edge seta was ob-
served in the third outer segment.

Occurrence. The S/S Thor has collected three females of this species at the following stations:

19/6 1904 St. 152 65°oo L. N. 28°io L. W. Yt. 1000 M. Wire.

■V7 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire.

Vg 1905 St. 167 57°47 L. N. ii°33 L. W. Yt. 1500 M. Wire.

Distribution. This species has only been recorded twice, namely from the Gulf of Guinea in a
gathering from 85 fathoms (5/^ 4°26 L. S. 10° L. E.), and from the west coast of Ireland "on four sta-
tions at depths of from 400 to 680 fathoms".

Remarks. Though this species differs from that described by Scott by less robust shape, by

4 for 5 amalliform setae of the maxillae, and by the slightly different shape of the fifth foot, it seems

natural to regard the two as identical. It seems to be nearly related to S. obttisi/rons, but differs by a

more robust shape, bv the structure of the third pair of legs, and by the longer antennulae.

26*

Text-fig. 64.

Scaphocalanus robtisttis Th. Scott fQ.

a. Head X 18. b. genital somite X 18.

c. Pes I sin. X I35-

204

COPEPODA

65. Scolecithricella minor Brady.
(PI. VII fig. 13; PI. VIII figs 10 a— c; text-figs 65 a— c.)

1883.? Scolecithrix minor n. sp. Brady, pp. 58—59. P'- ^VI

figs 15—16, pi. XVIII figs I 5.
1S92. ? — — Brady. Giesbrecht, p. 266.

1894.? - — — Th. Scott, p. 50.

1898.? — — — Giesbrecht & Schmeil, p. 46.

1902.? — Roineri 11. sp. Mrazek, pp 513— 515, Taf. 6,

text-figs II — 13.
1903. Scolecithricella minor Brady. G. O. Sars, pp. 55—56, pis

XXXVn— XXXVIII.

1904. Scolecithrix minor Brady. Wolfenden, p iir.

1905. — ^ — Th. Scott, p 223.

1905. — — — Farran, p. 35.

1906. Scolecithricella minor Brady. Pearson, p. 18.

1907. — — - Koefoed & Damas, p. 397.
190S. — — - Farran, p. 51.

1908. Scolecithrix minor Bradv. v. Bremen, pp.73 — 74,text-f. 85.
1913. Scolecithricella minor Brady. Stephensen, pp. 314 -315.

Text-fig. 65. Scolecithnccl/a minor Brady.

a-b. Yd'— 9 (St V'. Abdomen X 87.

c. Ycf (St. IV). Abdomen X 57-

Description, f?. Size of specimen from Ingolf St. 40 was 1-52 mm.; anterior divi.sion 1-22 mm.;
urosome 03 mm. Sars's specimens measured 1-40 mm.

The antennulae extend slightly beyond the end of the thorax; the segments i and 2 are in-
distinctly separated, and so are segments 24 and 25; the segments Sf^g are almost completely fused
with 10. The Sp of segment 24 is placed terminally, and extends distinctly beyond the end of segment
;, 1, c 25. The month-limbs are completely like Sars' figures, and so are

the natatory legs; the second basipodite of the fourth pair of legs
has 3 — 4 rather stiff, marginal setae. In lateral view the third as
well as the fourth foot has in the second basipodite an outer-edge
lamina, which terminally is produced into a small tooth, much big-
ger in the fourth foot; this lamina has in the third pair, almost in
the middle, about 5 rather .short and delicate teeth.

The labniiii and area in front of it is in lateral view very
much like Sars' figure PI. XXXVII; the labrum proper and its an-
terior portion, which is only slightly prominent, have onh' a slightly
pronounced concavity between them. The anterior surface of the labrum is like that of 6'. ovata (cf. PI.
VII fig. 14 b); most anteriorly a transverse row of long slender bristles is found, continued laterally and
posteriorly into a row of shorter setae; behind this, almost in the middle, a transverse row of shorter
setae is found.

The oral S7tr/ace of the labrum shows a great similarity to that of 5. ovata (cf. fig. 14 c), but
the anterior lateral group is not well separated from the marginal setae, and the following group is
not convex outwards, and is directed towards the second median circular spot. The rudimentary lamina
labialis (PI. VII fig. 13 a) scarcely shows features of great interest. The arrangement of hairs upon
and behind the labial lobes shows great similarity to PI. VII fig. 14 b, but the median and the lateral
groups of hairs are fused.

fc?. Size of specimen from Ingolf St. 40 was 1-34 mm.; anterior division 0-99 mm. ; uro,some
0-35 ram. Sars' specimens measured 1-40 mm.

The antennulae are like Sars' figure, but segments 200^21 bear only a single seta not two.
The mouth-appendages are very much like those of the female, except the mandibulae which have
the third basipodite distinctly longer than wide, the maxillae which have the sensory setae better
developed, and the maxillipeds which are shorter and more clums^•. The natatory legs are scarceh-
different from those of the female. The fifth font is like Sars' description; the left endopodite

COPEPODA

205

which is placed on a small protuberance, is short and clumsy, and indistinctly divided into two
segments.

Yq (St. V). Size of female from Ingolf St. 70 was 1-15 mm.; anterior division 090 mm.; urosome
0-25 mm. A yoiing male from same station measured 1-17 mm.

The shape of the body is practicall\- like that of the adult females; the first as well as the
fifth thoracic somites are fairly well marked in front. The antennnlae extend somewhat beyond the
end of the body, but the measurements are scarcely different. The third and fourth feet are like those
of the adult female, and so is the fifth foot, except for the very indistinct lateral seta. The only dif-
ference between male and female is found in the structure of the fifth foot, which is seen in PI. VIII
figs 10 a — b (textfigs 65 a— b).

Yg (St. IV). Size of female as well as of male from Ingolf St. 19 was 0-95 mm.; anterior division
074 mm.; urosome 0'2i mm.

The shape of the body is in main Hke adult female. The distal segments of the antennnlae are
comparatively longer. The only difference between the sexes is found in the fifth pair of legs, the
structure of which is seen in figures (text-fig. 65 c and PI. VIII fig. 10 c).

Occurrence. Of this species the Ingolf Expedition has taken a big number of specimens while
the S/S Thor has not taken any specimens in the samples taken with the young-fish trawl.

In Davis Strait and in the Atlantic west of Greenland, the Ingolf Exp. has gathered it at
6 stations.

5/7 95 St. 29 63°34 L. N. 54°3i L. W. V'. 50—0 fathoms. Temp. surf. 3-5° C. i f?.

_ — 3-9° C. 31 f? (i with sperm.), 10

fc?, 2 y? (V).
- — 4-2° C. 25 f? (2 with sp.), 13 f d-,

14 y? (V), 3 yc? (V), I yc? (IV).

V7 95 St. 27 64°54 L. N. 55°io L. W. V'. 200—0
25/(3 95 St. 24 63°o6 L. N. 56"oo L. W. V'. 100— o

276 95 St. 25 63°30 h. N. 54°24 h- W. V'. 200—0
28/7 95 St. 36 6i°5o L.N. 56°2i L. W. V'. 100— o

30

ij 95 St. 38 59°i2 L. N. 5i°o5 L. W. V'. 100— o

2-9° c. 82f?,i2fd',i7y?, isyc?-

8-5= C. 3f?, II y?, eye?, 3 3'?

(IV), 3 yc? (IV).

10° C. 95 f ? (lo with sp.), 15 f d",
5y?(V), loyc^(V).

In the Atlantic south-west of Iceland and east of Greenland the species was taken at 5 stations.

2% 95 St. 20 58°2o L. N. 40°48 L. W. V". 200—0 fathoms. Temp. surf. 6-i^ C. 40 f? (i with sp.), 16 fc?,

i3y?(V),ioyc?(V).

•% 95 St. 19 6o°29 L.N. 34°i4 L. W. V. 300-0 - - 9° C. 100 f? (10 with sp.), 30

i^ (3 with sp.), 15 y? (V), 5 yc? (V), i y? (IV).
•7/6 95 St. 18 6i°44 L. N. 30°29 L. W. V'. 200-0 fathoms. Temp. surf. 10° C. 55 f ? (5 with sp.), 25

fc?, I y?(V), I yc?(V).

'3/6 96 St. 80 6i°o2 L. N. 29°32 L. W. P. 100— o - — 8-5° C. i yc? (V).

"^/f, 94 St. 17 62°54 L.N. 26^34 L. W. V. 200—0 — — 9'i° C. 4!?, 2 fc?, i y?, i yd*.

°= Ay

2o6

COPEPODA

In Denmark Strait it was taken at 5 stations.

27/5 96 vSt. 95 65°i4 L. N. 30°29 L. W. Closing net. 700 fathoms 2 f ?.

2% 95 St. II 64°34 L. N. 3i°i2 L. W. V'. 200-0 fathoms. Temp. surf. 8-2° C. 10 f?, i fc^, 5 y?, 5 vc?.

2% 95 St. 10 64°i9 L. N. 28°52 L. W. V'. 200-0 — - 7-9° C. i f?, 2 f^.

=^0/5 95 St. 9 64°i8 L. N. 27°io L. W. V. loo-o - — 7-9° C. i f?, 3 f c?.

•9/, 95 St. 8 63°56 L. N, 24°4o L. W. V. 100-0 — — 8-5° C. 65 f? (2 with .sp.), 37 f d",

iy?(V).
In the Atlantic south of Iceland it was taken at 6 stations.

9/s 95 St. 40 62°oo L.N. 2i°36 L. W. V. loo-o fathoms. Temp. surf. 13-5° C. 60 f?, 15 fd", 24 y? (V),

1.5 yc? (V), 2 yc? (IV).
3/6 96 St. 68 62''o6 L. N. 22=30 L. W. V. 100— o — — 8-8° C. 4f?.

i/ft 96 St. 63 62°4o L.N. i9°o5 L. W. V. lOo-o - — 8-3° C. 26 f?, 6 fd*, 5y?(V).

'8/596 St. 54 63°o8 L. N. i5°40 L. W. V. 100— o — — 9° C. 10 f ?, 6 f d", 3 y?, 2 yj".

•3/5 96 St. 49 62°o7 L.N. 15=07 L. W. V'. 100— o — — 9'3° C. 15 f?, 5 fc?- ^ y$, 4 yd".

'==/^ 96 St. 47 61^32 L.N. i3°4o L. W. V'. 100--0 — - io-6° C. 58 f? (10 with sp.), 22

fd*, 3y?(V), 2y5(V).

The Danish East Greenland Exp. 1900 has in surface hauls taken a few specimens, viz:

24/g p. 390 8 p. m. 6i°o6 L. N. 15=26 L. W. 4 f ?.

F. 392 12 p. m. — — I f?, I fd*.

25/g F. 393 2 a. m. 60=29 L- N. i2°io L. W. 15 f ?, 6 f d''

F. 402 8 a. m. — — i f $.

F. 403 - - 3 f ?, I yd' (V).

2^/9 F. 412 8 p. m. 60=13 L. N. 9=42 L. W. r f?.

In the Iceland-Fseroe channel the Ingolf-Exp. has taken it in 5 samples.

'4/5 96 9-30 a.m. 64=13 L. N. 15=00 L. W. Apst. 6 Temp, at surf. 7-8° C. i f?, i yd* (V).

•5/5 96 St. 52 63=57 L. N. 13=32 L.W. V. 200-0 fathoms. — 8-3° C. 8 f?, 2 fd", 2 y?, i yd"-

2°/j 96 St. 57 63=37 L. N. 13=02 L.W. V. ioo~o — — 8-2° C. i f?, 3 fd", i y?, i yd".

"/? 96 St. 45 61=31 L. N. 9=45 L.W. V. 200-0 — — 9-1=0. 16 f? (4with sp.), Sfd",

9y?(V), 4yc?(V).

"/s 95 St. I 62°3o L- N. 8=21 L.W. V. 50-0 - — 10° C. 3 f?.

North-east of Iceland the Ingolf Exp. has taken it at two stations.

25/^96 St. 119 67=53 L- ^- io'i9 L.W. P. 100— o fathoms. Temp, at surf. 5' C. if?.
^^7 96 St. 117 69=13 L.N. 8=23 L.W. V. 100— o — — 4-1° C. iy?(V).

Outside the Ingolf area, specimens were examined from two localities, viz:

Dan. East Gr. Exp. 1900 "/„ i p. ni. 63=33 ^- N. 0=04 L.W. Closing net. 75—50 fathom.s. i f?.

J oh. Petersen 73° L. N. 8= L. E. 3f?, 2y?(V).

COPBPODA 207

Distribution. Brady's specimens were taken in the Indian Ocean 47° L. S. 45° L. E. at the sur-
face. By Th. Scott it was recorded from the Gnlf of Guinea, and, according to Farran, it is fairly com-
mon off the west coast of Ireland at depths of from 100 to 1000 fathoms; occasionally it has been found
at or near the surface. According to Sars it is a true pelagic form (often occurring close to the sur-
face of the sea), wliich is found along the greater part of the Norwegian coast as far north as Lofoten
Islands, as well as sometimes in the open sea. In the sea between Spitzbergen and Greenland as far
north as 8o°i7 L. N. the Due d'Orleans has gathered this species in 32 samples from about 80, between
7/7 and i5'8 1905, as well in cold as in temperate water. It was neither found at the very surface
nor below 500 meters, but in 12 out of 14 samples taken at a depth of from 100 to 200 meters, gene-
rally scarce never abundant; in 8 samples adult males as well as females were found at a depth of
from 20 to 400 meters.

Remarks. I have followed Sars in referring the northern form to Brady's species from the
Indian Ocean, though his description is too incomplete for a certain identification. In spite of minor
differences, f. inst. in the .shape of pes V of the adult female, I am fairly convinced that Mrazek's
S. Rovieri is identical with this species. As the species has not been found, as far as I know, in any of
the extensive collections from the vSouth- and Mid-Atlantic or Indian Oceans, I think we are entitled
to regard this species as one which has its chief centre of distribution in the North-Atlantic and in a
less degree in the Arctic seas cummunicating with it. It seems not to have been found in the North
Sea proper or adjacent waters; may be on account of lower salinity.

The records of the "Ingolf," which are all from the months Ma\- to July, and almost all with
the vertical net down to about 100 fathoms, tell the same story as the above mentioned records of the
Due d'Orleans; that the species in these regions and at this sea.son is only exceptionally found at the
surface ; if it were not so, it must have been found in several of the numerous surface samples from
the Ingolf or the Danish East-Greenland Exp. It is worth recording tliat the species was found in
several surface samples gathered from the mentioned expedition in the month of September, south-
west of the Faroes. The Ingolf material does not allow any final conclusion about the time of pro-
pagation, but as adult males were found in 19 out of 24 samples (in a percentage varying from about
10 to 50) taken from May to Juh-, and as spermatophores were often attached to the genital somite
of the female as well as sometimes to that of the male, it is almost certain that the species is propagating
then. The Due d'Orleans found only males in 8 out of 32 samples. Adult males were gathered south-
west of the Faeroes in the month of September. Young animals of the penultimate stage were found
in most samples, except in those from the month of September.

66. Scolecithricella Ingolfii n. sp.
(PL VIII figs II a— c).

Description. i% The shape of the body is practically like that of S. minor; the head is perhaps
a little more raised. The lateral corner is, like that of preceding species, somewhat triangularly produced.
The antfiimdae and oral appendages are completely like those of X mnior.

The first pair of legs is scarcely different; the first inner segment of the second foot has a

2o8

COPEPODA

fairly distinct pointed onter spine; the outer-edge lamina of the third pair of legs has no spines.
Along the inner margin of the second basipodite only two setae are observed ; the inner terminal tooth
of the third basipodite is longer and more slender. The /f//// pair of legs is fairly well developed, with
three indistinct segments (fig. iib); on the left side two indistinct terminal setae are found; on the
right side the endopodite is indicated by a small process, and the exopodite has, inwards, a distinct
spine. A similar asymmetric structure was also observed in a specimen from Ing. St. 19. In a spec-
imen from lug. St. 9, the left leg had a somewhat better developed endopodite, and the exopodite had
a terminal and an inner seta, fairly long and placed nearer the tip than the base. In the specimen
from 0. Exp. 1900, the legs were symmetrical, and showed, as seen in PI. VIII fig. 11 c, a somewhat
different structure.

Occurrence. The Ingolf Expedition has gathered this species at three stations viz:

V7 1895 St. 27 64°54 L. N. 55° 10 L. W. V". 200—0 fathoms Temp, at the surface 3-9° C. 2 f ?.
'Vs 1895 St. 19 6o°29 L. N. 34°i4 L. W. V. 300-0 — — — 6° C. i f?.

2% 1895 St. 9 64°i8 L. N. 27°io L. W. V'. loo-o - - — 7° C. 2 f ?.

The Danish East-Greenland Expedition has -s >, 2 p. m. 1900 6o°i9 L. N. 22°io L. W. F. 399
<rathered a single adult female.

As far as I was able to ascertain, this species has not been described hitherto. It is very much
related to 6". viinor^ and it is not without doubt that I have established it as a new species, as. at
almost all the localites it was found in conipau}- with that species; but as the character found in the
much longer fifth foot was found to be fairly constant in spite of small variations, I thought it
right to do so.

67. Scolecithricella ovata Karran.
(PI. VII figs 14 a— d; PI. VIII figs 12 a— f).

1905. Scolecithrix ovata u. sp. Farraii, p. 37, pi. VI figs 13 — 18, 1908. Scolecithrix ovata Farr. Farrau, p. 51.

pi. VIII figs 1 — 5. 1908. — — — V. Bremen, p. 72, fig. 83.

1906. Scolecithricella ovata Farr. Pearson, p. iS.

Description. Size of specimen from lug. St. 19 was 232 mm.; anterior division 1-84 mm.; uro-
some 048. Another specimen measured 2-5 nmi. Farran's specimens measured 2-3 mm.

The shape of the body is in main features like F^'arran's description; the head is fairly well
raised, and the rounded lateral-corners are slightly produced. The first and the fifth thoracic somites
are not marked out in front. The rostrum consists of two short, obtuse, slightly divergent teeth, arising
from a short lamelliform undivided process, to which are attached fairly slender and apparently obtuse
rostral filaments, several times longer than the rostrum proper and, in direction downwards and back-
wards, reaching beyond the insertion of the antennulae; these filaments are wanting in most specimens.

The abdomen has the genital somite only slightly produced below; the receptaculuni seminis
is elongated-pear-shaped, and generally very prominent. The comparative length between the abdominal
somites and the furcal rami, which are almost twice as long as wide is 22, 12, 14, 3 and 12.

The anie7iTnilae\\a.\-e 23 segments of which the segments 24 and 25 are completely fused; they reach

COPEPODA 26^

about to the end of the third abdominal somite. The anfeiDiulnc appear rather clumsy, and their
measurements are scarcely different from Farran's figures. A proximal seta, in addition to the distal
one, was found in segments 12, 14 and 18; in contrast to Farran's fig. 14 no seta whatever was ob-
served in segment 10; the posterior seta of segment 24 is sliort, and scarceh' extends beyond the end
of segment 25. The anterniac are like those of .S". iiiinor, but the inner lobe of the endopodite has only
7 setae. The mandibular have on the inner side of the long and slender third basipodite two long
setae placed close to each other, of which the basal is the longer and stronger; the last segment of
the exopodite has 9 long setae. The iiiaxilhtlae have 7 + 2 setae in the outer lobe. Li I has 2, Li II
3 setae, Basp. Ill has 4 setae and Ri I— III 3+3 setae. The exopodite has 5 setae. "1^^^ maxillae zx^
like Farran's figure, and possess numerous vermiform, but no amalliform, setae (PI. VII fig. 14a); the
maxillipeds are like Farran's figure, but the second lobe of the second basipodite bears a fairly long,
terminally hooked, and soft sensory seta.

The firstfoot has a well developed Se in the first outer segment, almost reaching the middle of the
following segment. The second foot has the second basipodite rather broad ; medially proximally to the
insertion of Si a small tooth is observed, and laterally the margin is proximally produced into a strong
tooth; the Se of the first outer segment is long and slender, and the St of Re III has about 55 basally
fused teeth. The spinulation of the posterior surface is better developed than indicated by Farran.
A glandular pore was observed at the base of Se 3 Re III. The third pair of legs has a well devel-
oped outer tooth in the second basipodite, and a short inner one, resembling that in the second foot
of 6". obtusifrons. The fourth pair of legs has no inner marginal bristles in the second basipodite, and
no outer tooth. The St has a rather curious structure, as the marginal serrations are not completely
coalesced basally, leaving an elongated fenestra. Spinulation, consisting of about 15 rather small teeth,
is found on the posterior surface of the second inner segment.

The: fit h pair of legs is in the main features like Farran's figure, with the first basal segment
well distinguished, and with the second more or less well separated from the broad lamellar third
segment. The legs are generally asymmetrical, partly because the articulation is better developed on
the left than on the right side, and partly because the number of setae is rather variable. On the left
side we generally find a shorter terminal and a longer distal seta as figured by Farran, on the right
sometimes the terminal and sometimes the medial seta is absent, but often both are present.

The anterior portion of the labriim is distinctly prominent in front; the anterior surface shows
a rather simple arrangement of the bristles (fig. 14 b) most similar to that of 5. obtusifrons, though
less complicated; in addition to the marginal rows of bristles an anterior transverse distinctly convex
row, composed of several units, and a posterior shorter one are observed. The oral surface of the labrum
has the anterior lateral group fairh' well separated from the marginal rows (fig. 14 c); the posterior
groups of the longitudinal series are, as seen in figure, more or less fused. As seen in fig., the trans-
verse median groups are rather poorly developed. The structure of the "lamina labialis" etc. is in the
main like that of the preceding species. The arrangement of the hairs upon and behind the labial lobes
show.s, as seen in fig. 14 b, a ver\- marked difference between a central and two lateral groups.

The intestine is not straight, but distintlv twisted, at least vertically, though in a le.ss degree

than in Lophnthrix frontalis.

27

The Ingolf-Rxppdition. III. i. '

2IO COPEPODA

Yo (St. V). Size of young female from lug. St. 19 was i-86mm.; anterior division 1-47; urosome
0-39. Another female from Thor St. 82 measured i-6 mm.

The shape of the body is Hke that of the adult female; the comparative length of the abdominal
somites and the furcal rami is 7, 9, 9, n and 9. The antennulae reach the base of the furca; the
distal segments are comparatively longer. The inner lobe of the last segment of the endopodite of
the anfennac has 8 setae, in other respects the mouth appendages were scarcely different; no dif-
ference of interest was found in the structure of the natatory legs. The Jifih pair of legs in the female
is scarcely different from that of adult, but showed in the male, as seen in fig. 12 f PI. \'III, a rather
characteristic structure, as the left leg is much longer than the right one.

Yc? (St. IV). Size of male from Ingolf .St. 27 was 1-38 mm.; anterior divi.sion i-i mm.; uro-
some 0'28.

The difference between this and the preceding stage is found in the abdomen, consisting of
three somites, the comparative length of which was 6, 9, 12 and 7. The antennulae reach only to the
middle of the last abdominal somite.

The first foot differs from that of preceding stage by the fused Re II — III; the second foot
showed the same feature, and its second basipodite has no outer tooth, while the spinulation was
scarcely different. The \&it fifth foot is somewhat longer than the right, and each foot consists of three
segments; no setae were observed.

Occurrence. The Ingolf has gathered this species at 4 stations in Davis Strait:

1/7 95 St. 27 64°54 L. N. 55°io L. W. V. 200—0 fathoms Temp, at surf. 3-9° C. 3 f?, i y c? (IV).
^Ve 95 St 25 63°30 L. N. 54=25 L. W. V. 200-0 - — 2-9° C. 9 f ?, 5 y? {\).

3% 95 St. 38 59"i2 L. N. 5i°05 L. W. V. 100— o — — io° C. 6f?.

25/6 95 St. 24 63^06 L. N. 56°oo L. W. V. 100— o — — 4-2° C. i f?.

In the Atlantic south-west of Iceland it was taken:

=>% 95 St 20 58°2o L. N. 40°48 L. W. V. 200—0 fathoms Temp, at surf. 6-i° C. 2 y? (V).

'8/6 95 St 19 6o°29 L. N. 34=14 L. W. V. 300-0 — - 9^ C. 25 f?, 3 yd" (V), 3 y?(V).

'7/6 95 St. 18 6i°44 L. N. 30^29 L. W. V. 200—0 — — 10° C. if?.

'6/6 95 St 17 62=54 L. N. 26°34 L. W. V. 200-0 - — 9-1° C. 5 f ?.

In Denmark Strait the Ingolf took it:
'% 95 St II 64°34 L. N. 31=12 L. W. V. 200-0 fathoms Temp, at surf. 8-2° C. i f?, 2 y? (V).

In the Atlantic south of Iceland:
■V5 96 St. 47 61=32 L. N. 13=40 L. W. v. loo-o fathoms Temp, at surf. io-6° C. 5 f$.

The "Thor" has gathered the species at a single station:

8/6 1905 St 72 57=47 L. N. ii°33 L. W. Yt 1500 M. Wire 2 f?.
'5/6 1905 St 82 5i°32 L. N. 12=03 L. W. Yt. 1200 M. Wire i y?.

Distribution etc. This species has previously been recorded only from the west coast of Ire-
land, where it seems to be of frequent occurrence over deep water from the surface to 1000 fathoms,

1

1
I

COPEPODA 2u

but only in small numbers. In spite of small differences I do not doubt that my specimens ought to
be referred to Farran's S. ovata. As the maxillae do not possess any amalliform setae, I have referred
the species to Scolecithricella, though in several respects it shows great similarity to Scaphocalanus
obtusifrons^ and perhaps is more related to this species than to .SV. minor.

68. Lophothrix frontalis Giesbr.
(PI. VII figs 7a-d; text-figs 66 a— f and 67 a— d).

1895. Lophothrix froutaHs n. sp. Giesbrecht, p. 254, pi. II. 1906. Scolecithrix frontalis Giesbr. Esterly, p. 65 pis 9&13.

1898. Scolecithrix frontalis Giesbr. Giesbrecht & Schmeil, p. 49. } 1908. Lophothrix frontahs Giesbr. Farran, p. 58.

'903' — — — J. C. Thompson, p. 21. 11908. Scolecithrix frontalis Giesbr. v.Bremen, pp. 79--80, fig. 93.

1904. Lophothrix frontalis Giesbr. Wolfenden , p. 120 pi. IX | 1909. Lophothrix frontalis Giesbr. A. Scott, p. 99, pi. XXVI figs

figs 41—42- i 11 — 20, pi. XXlX figs I -10.

1905. — — — G. O. Sars, p. 6. j 1911. — — _ Wolfenden, p. 268.

1906. — — — Pearson, p. 19. |

Description. f$. Size of female from Thor St. 72 was 6-45 mm.; anterior division 5-18 mm.;
urosome 1-27 mm. Giesbrecht's specimen measured 6-6 mm., Scott's 7-4, and Wolfenden's 5-5— 60 mm.

The genital somite is slightly produced below and has au elongate receptaculum seminis, which
is directed upwards and forwards (text-fig. 66 a). Along the hinder margin of somites 2—4 a well devel-
oped serration is found; the third and the fourth somites possess dorsally and anteriorly transverse
groups of short spines.

The antennulae, which extend beyond the end of the third abdominal somite, consist of 24 seg-
ments, as segments 24 and 25 are fairly well separated, "^sthetasken" are, in contrast to Scott's figure,
beyond segments 8<^9 onl)- found in segments 12, 14, 19 and 25. The segment 10 possesses a well
developed seta, and a proximal seta is beyond segment 8^9 only found in segments 12, 14 and 18.
The Sp of segment 24 e.xtends distinctl\- beyond the end of segment 25. Segments 8<^9 are only a
little shorter than segment 18, which is a little longer than segment 17 as well as 19, which is i-2 as
long as segment 20. The antennae are like Giesbrecht's figure, with the exopodite a little longer
than the endopodite, which has 8 setae in the Li and 6 in the Le. The third basipodite of the iiian-
dibulac has three long convex setae; the first inner segment has 2 setae, and the second has g. The
maxillulae are like those of 5. iiiagnus, with 7 + 2 setae in L,e, 14 setae in Li I, 2 in Li II, 5 in Li III
and 4 or 5 in basipod. III. The Ri I has 3 setae, the Ri II f^^ III 5 setae, and the Re has 9 setae.
The .shape of the maxillae is like that of fig. 14 a; amalliform as well as vermiform setae are found.
The maxillipeds are like Giesbrecht's description. The second, third and fourth pairs of legs do not
show the marked difference in the second basipodite when observed in lateral view in situ; in the
second and third feet an outer-edge lamina is found, but neither spines nor distal tooth. The first outer
segment of the first foot has no outer seta. The second foot has a well developed long outer spine in
the first inner segment, as figured by Giesbrecht; the anterior surface is smooth, but the posterior
surface has a number of short spines, as seen in fig. 7 a PI. VII. Tht fourth pair of legs has the inner
margin of the second basipodite smooth; the third basipodite has, like the third pair, a small inner
tooth on the anterior surface near the end ; a few teeth were found only on the posterior surface of the

two inner segments. The fiftli pair of legs is scarcely different from Giesbrecht's description.

27*

312

COPEPODA

k * O -

The lahruiii is, as seen in Wolfenden's fig. 41, more elongated than that of ^'. wagiuis (PI. VII
fig. 8 a), and strongly produced in front; the hinder portion of the labrum is, as in most other species,
marked by an anteriorly convex line. I am fairly convinced that the anterior as well as the posterior
portion of the labrum belongs to the mandibular and not to the antennal somite ; the anterior portion,
accordingly, does not correspond to the epistoma of Euchatc. The arrangement of bristles on the
anterior surface is very characteristic (PL \'II fig. 7 b). In the middle, most anteriorly, is a forward convex
row of about 30 long bristles. A little more posteriorly we have on each side a long row extending
laterally from the middle in front towards near the hinder margin; the setae of this row are decreasing
in length posteriorly; the right and the left parts establish an acute angle open posteriorly, and,

thus include a more posterior row, forming a more obtuse
angle, of shorter setae.

In addition to the marginal setae, posteriorh' irregular
groups of short setae are foinid on each side. The oral
surface of the labrum is rather characteristic, the first
group is poorly developed, consisting of small granules
and is well separated from the groups 2 — 4, which are more
or less fused and consist of fairly strong, densely placed
setae; behind, a group of small granules is observed (fig.
7 c, which is turned upside down). A lamina labialis (fig.
7 d PL VII), consisting of a median and two lateral parts,
is found. In front of the serrula 6-dentata are two rather
irregular rows of delicate setae, as seen in figure. Between
the serrulae at least two groups of short spines and a
longitudinal row are seen on each side. The lobus labialis
possesses a wide inner row of numerous hairs, and an
outer one of few hairs; both rows start posteriorly from
a median group consisting of an inner portion with
numerous densely placed hairs, and an outer portion with
scattered hairs. More posteriorly and laterally, two groups
of a few hairs as well as irregularly placed hairs are found. The intestinal tract is curiously twisted.
In front of the oesophagus a short coecal sac is observed ; behind, the stomach is gradually attenuated,
and forms a slight ventral convexity. At the insertion of the third pair of legs the intestine is
suddenly, in a sharp bend, turned upwards and directed forwards, being thus placed dorsally to the
mentioned part; somewhat in front of the maxillipeds it is continued through a second curvature
into the intestine proper.

Text-fig. 66. Lophothrix frontalis Giesbr.

a. f9. Genital somite X 33- b. Y9 (St. V) Pes V

X 59- c. Yd" (St. V). Abdomen X 33. d. YcflStV).

Pes V X 59. e. Yo" (St. IV). Abdomen X 3.v f. Yd"

(St IV). Pes V X 59-

i^. Size of male from Thor St. 183 was 5-66 mm.; anterior division 4-19 mm.; urosome 147 nnu.
Scott's specimens measured 575 mm.

The body is slender and attenuated in front as well as behind; in dorsal view, scarcely in
lateral, a trace of rostrum, is observed. The rostrum is on each side continued into two fairlv long:

COPEPODA

213

and slender spines (text-fig. 67 a). The fifth tlioracic somite is well distinguished in front, and the
regularly rounded lateral corners are scarcely produced.

The abdomen is one third as long as the anterior division; the comparative length of the
abdominal somites and the fnrca is 18, 67, 53, 48, 10 and 18.

The antennulae extend at least to the end of the third abdominal somite ; the shape is similar
to that of ^". magmis, but the proximal part is straighter, the restrictions at the base of the basal
segments are less pronounced, and the angle between segments 14 and 15 in less marked. Segments
8<>3 9 are almost completely fused with 10—12, segments 20 and 21 and 24 — 25 are completely fused.
The appendages are scarcely different from those of S. viagnns\ the segment 20 does not possess any
setae. The segments 8'>ii2 are i-i as long as segments 23 — 25, not, as in 6". ywa^w?/^ and related species,
much (1-5) .shorter, and segment 22 is 1-2 shorter than segment 19. The antenna are scarcely different
from those of adult females, and the mandibulac are very much like, but the manducatory parts are less
powerful, and the third basipodite is comparatively wider, with two short setae inwards, and a more
distally placed knob representing a third one. The \a I of the inaxillulae is fairly well developed,
and has at least 12 rather short and soft setae; in Li
III only 4 setae were observed, but in other respects
scarcely any difference was observed. The ii/axilluc
have the sensory appendages, especialh- the amalliform
ones, slightly developed; the maxillipeds are like those
of S. magnus.

The natatory legs are scarcely different from
those of the female. The Jiftli pair of legs extends
almost to the end of the abdomen, and shows great
similarity to that of S. magnus. The right endopodite,
which extends somewhat be>ond the end of the first
outer segment, is styliform, with the terminal part

fairly well articulated. The right exopodite (text-fig. 67 c) has the first segment articulated upon a
long outer process of the third basipodite as long as the segment itself; the two pieces form a natural
joint, elongated and outwards convex; the second outer segment is much shorter than the first; the
third somewhat lamelliform segment is again somewhat longer, convex inwards, with a distinct angular
process in the middle directed forwards, and produced into a pointed eminence, at the base of which
a small conical process is found. The basal segments of the left leg are long and slender, and of almost
equal length; the left endopodite (text-fig. 67 d) is like that of 5. magnns, with the two first segments
long and slender, and the third rather .short and pointed; the left exopodite is somewhat shorter than
the endopodite, and its third segment is triangularly attenuated, with fairly long setae inwards and
terminally and short ones outwards.

The anterior snrfacr of the labruin is very much like that of the female; anteriorly three
irregular series of apparently very short setae are found; the series along the hinder margin is wanting.
The oral surface has anteriorly a small conical process on each side, behind which at least two striated
median spots are found; on each side an irregularh- striated protuberance was found; no hairs were

Text-fig. 67. Lophothrix frontalis i(J.
Head > 18. b. Abdomen X 18 c. Pes V dext.
Re II-III X 59. d. Pes V sin, X 59-

,j. COPEPODA

observed. The laviina labialis seems to be represented by a transverse crest; in front of it on each
side a longitndinal area of very minute hairs is found, and behind, a serrnla 6-dentata consisting of
rather short setae is observed. The labial lobes are well developed, but no setae are observed upon them.

Yq (St. V). Size of female from Thor St. 72 was 4-88 mm.; anterior division 3-80 mm.; urosome
i-o8 mm. Male from the same station measured 5-37 mm.

The )oung animals are in most respects like those of the adult females; the fifth thoracic
ter"-ite is distinctly marked out (text-fig. 66 c). The only difference is found in the structure of the
fifth foot, which in one female was scarcely different from that of the adult, while in another, probably
a variation, the distal outer seta is comparatively short, but in addition to it another proximal one is
observed, and the endopodite is indicated by a short rounded process (text-fig. 66b). In the male the
setae are short, and a long endopodite is found (text-figs 66 b— d).

Yq (St. IV). Size of male from Thor St. 167 was 3-48 mm.; anterior division 2-90 mm.; urosome

0-58 mm.

The shape of the body shows the usual differences; the lateral corners are slightly more produced
(text-fig. 66 e). The mouth-limbs are scarcely different, but the 3 last natatory legs have the number
of segments reduced; the second foot, f. inst, has the 2 last outer segments fused with 3 outer spines
onlv; the number of teeth on the posterior surface is smaller. The fi/f// /oof of the female has 3 seg-
ments, a strong terminal spine, and a short outer spine, but no inner one. The fifth foot of the male
is, as seen in text-fig. 66 f, distinctly smaller than in preceding stage.

Occurrence. The lugolf has not taken this species, but it was gathered at several stations by
the "Thor".

In Denmark Strait:

'9/6 1904 St. 152 65°oo L. N. 28°io L. W. Yt. 1000 M. Wire 10 f?, i y? (V), 4 yc? (V).

^0/6 1904 St. 153 65°27 L. N. 27°i2-5L.W. 6 f?, i y^ (V).

"/6 1904 St. 154 65=27 L. N. 27°io L. W. 3 f?, I fc?, 2 y? (V).

In the Atlantic South of Iceland:

•Vs 1904 St. 78 6i°o8 L. N. 28° L. W. i y? (V).

Vg 1904 St. 285 62°49 L. N. i8°46 L. W. 14 f?, i y$ (V), i yc? (V).

"/7 1904 St 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 15 f?, 8 f J".
^5/. 1904 St. 104 62°47 L. N. i5°03 L. W. 7 f?; i f c?, i y? (V), 2 yd (V).

In the Fseroe-Iceland channel:

"/s 1904 St. 99 6i°i5 L. N. 9°35 L. W. Yt. 1700 M. Wire i f?.

Yt. 900 M. Wire 3 f $.

4/8 1904 St. 230 63°io L. N. 7°3i L. W. Yt. 1200 M. Wire i f?.

'Vs 1904 St. 78 6i°o7 L. N. 9°3o L. W. 2 f?.

29/8 1905 St. 165 6o°oo L. N. io°35 L. W. Yt. 1000 M. Wire i f?, i yj" (V).
Outside the Ingolf area:

'5/6 1905 St. 82 5i°32 L. N. i2°03 L. W. Yt. 1200 M. Wire 5 f?. i y?(V), i yd'(V).

Yt. 800 M. Wire if?, i yd* (V).

COPEPODA

215

Vy 1905 St. 167 57°46 L. N. 9°55 L. W. Yt. 1500 M. Wire 81 f?, i y? (V), i y? (IV).
% 1905 St. 72 57°52 L. N. 9*^53 L. W. Yt. 1500 M. Wire 58 f ?, 3 y? (V), 25 yc? (V), i yd* (IV).
2% 1905 St. 88 48°09 L. N. 8=30 L. W. Yt. 300 M. Wire 18 f?, 2 y? (V), 5 yd* (V).

Distribution. This species is probably distributed all over the Atlantic as far north as Den-
mark Strait and as far south as 35° L. S. It has been recorded from the Pacific (35° L,. N. 125°
L. W.), from the Gulf of California where, according to Esterly (1912 p. 321), it is found between 50
and 300 fathoms, and from the Malay Archipelago. According to Far ran it is a not uncommon species
in the N. E. Atlantic. "It was taken on every station at all depths from 330 to 11 50 fathoms, and in
fifteen out of thirty-four gatherings".

Remarks. In spite of a few minor differences, partly enumerated above, I regard this species
as identical with Giesbrech t's, Scott's and Wol fend en's species.

69. Scottocalanus Thorii n. sp.

(PI. VI figs 14 a— c, PI. VIII figs 14 a — b, text-figs 68 a — i, 69 a— d and 70 a — d).

1893. (Jnec. ■? Scolecithrix securifrons n.sp. Th. Scott, pp.47— 1905. nee. Scolecithrix persecans Giesbr. Esterly, pp. 168 — 167,

48, pi. IV.
1895. nee. — persecans n. sp. Giesbrecht, pp. 253 -

254, Taf. 3 figs 6~i2.

fig. 28.
1906. ?pars. Scottocalanus securifrons Scott. Pearson, p. 19.
190S. — persecans Giesbr. Farran, p. 58.

1898. nee. — — Giesbr. Giesbrecht &Schn]eil, j 1908. nee. Scolecithrix persecans Giesbr. v. Bremen, pp. 80— 81.

p. 58. 1909. nee. Scottocalanus persecans Giesbr. A. Scott, pp. 105 —

1903? — — — J. C. Thompson, p. 20. : 106, pi. XXVII figs 10—18.

1904.' — — — Cleve, p. 197. 191 1, pars. Lophothrix securifrons Scott. Wolfendeu, p. 268.

1905. Scottocalanus securifrons Soott. G. O. Sars. p. 7.

Description. f$. Size of female from Thor St. 82 was 4-69 mm.; anterior division 3-91 mm.;
urosome 078 mm. Esterly's specimens measured 4-6 mm.

The rostrum is very strong, and only terminally subdivided into two rather short divergent
branches without terminal appendages (text-figs 68 a— b). The eyes are well developed. The forehead
is surmounted b\- a short, rather prominent crest. The sh%pe of body is, as seen in te.xt-figs 68 c— d,
somewhat robust, and the anterior division is almost five times as long as the abdomen. The first as
well as the fifth somites are fused with the preceding ones; the lateral corners are somewhat triangularly
produced, but are obtusely rounded, with a small notch.

The genital somite, which is about as long as the following three somites, is moderately pro-
duced below, but the hinder and ventral corner does not project beyond the following somite. No
serration was observed along the hinder margin of the abdominal somites.

The antennulae extend at least to the end of the third abdominal somite; segments 8'^9 are
well separated from 10, and segments 24 and 25 are fairly well separated. The appendages differ from
those oi L. frontalis by wanting a seta in segment 10, and by the delicate Sp. of segment 24, which just
extends beyond the end of segment 25; the segments 8^9 have two soft setae (text-fig. 68 e). The
measurements are very much like those of L. frontalis. The exopodite of the antennae is almost 1-5 as
long as the endopodite, which has 8 setae in the outer and 6 in the inner lobe of the second segment.
The mandibular are in the main like those of L. frontalis, but the third basipodite has only two setae;

2l6

COPEPODA

the iiiaxilhdac differ from those of the mentioned species by 3 setae in the second inner lobe and 8
setae in the exopodite. The posterior margin of the Jiiaxillac is only slightly convex, and only a few
slightly developed amalliforra sensory setae in addition to the vermiform one were observed. The
maxillipcds are like those of the preceding species, but the amalliform seta of the second basipodite
is rather slender, and the endopodite is comparatively elongate.

In lateral view the second basipodite of the second and third foot has an outer-edge lamina
with a prominent distal tooth.

The first foot has 3 outer segments; the outer spine of the first segment extends somewhat

beyond the middle of the second segment; in the
outer margin of the third segment a distinct glan-
dular pore is foinid near the base. The second pair
of legs (text-fig. 68 f) has a large somewhat rounded
outer tooth in the first outer segment. The ter-
minal seta has about 30 well separated serrations.
The posterior surface of Ri II 'V' III has 6 strong
spines, and the anterior one a few shorter ones.
The posterior surface has a single row of teeth in
the second outer segment and two rows in the third.
Indistinct glandular pores are found at the base
of Se Re 11 and Se 3 Re III. The fhird pair of
legs has a well developed inner tooth terminally
on the anterior surface of the third basipodite; the
third to fifth serration of the terminal spine is
shorter than the more proximal and distal ones; the
arrangement of the spinules is less developed
than in the second pair of legs. The fourth foot
has a short clumsy second basipodite without mar-
ginal setae outwards; the endopodite has no teeth
posteriori}', but has a few on the anterior sur-
face of Ri II and III, as in the preceding pairs;
tlie exopodite is almost smooth. Well developed
glandular pores are found in Re I as well as in

Text-fig. 68. Scottocalanus Thorii n. sp. f9.
a. Head )< JS. b. Rostrum )< 33. c. Abdomen in dorsal
view X 15- d. Abdomen in lateral view X i5- e. Segments
VII — X of the antennulae. f. Pes II dext. in anterior view,
g-

;. Pes V in anterior view X 59- li. Base of spine in posterior u tt ttt t-i £j-ii i • x i u 4.1. ci

. ^, . „ . . . , ^. .^ Re 11 — 111. ine fift/i pair 01 legs has three rather

view X 150. 1. Base of spine 111 partly anterior view y. 59. . j r o

indistinct segments; inwards a small conical pro-
cess bearing a short spine and, with a rudimentary hair at the base of the strong outer spine, almost
extending to the end of the third abdominal somite; in the distal half the spine is interiorh- serrated,
and terminally, a few hairs are found outwards (text-figs 68 g— i).

The lateral view of the tabrum is like that of »?. niagnus, but the anterior part of the labrum
is less produced, and in front of it a smooth, rounded elevation is found. The anterior surface of the
labruvi (PI. VI fig. 14 a) shows some .similarity to that of L. frontalis (PI. VII fig. 7 b). Most anteriorly

COPEPODA

217

a curved row of fairly long setae, in the middle connected with the opposite side, is found; somewhat more
posteriorly, and extending from the middle anteriorly to the hinder margin posteriorly, an elongated
semicircular row is found (in fig. 14 a, this row is wrongly represented as being separated from that of
the opposite side); this row is several setae high, and the length of its setae decreases backwards.
More posteriorly another convex row of shorter setae is foimd, and between the end of this row and
the mentioned outer row a short oblique series is found. Posteriorly and laterally scattered hairs are
found, and more medially an almost transverse row. The posterior marginal setae are well developed.
The oral surface of the labrum (PI. VI fig. 14 b) .shows greatest siniilaritv to tliat of .V. obhtsifrons (PI.
VII fig. 9 c). Laterally, in front, a big area with short setae is ob-
served, belonging to the marginal system. The first lateral group
consists of a few granules, and is well separated from the three fol-
lowing more or less fused groups of fairh- strong setae ; posteriorly
one or two groups of more delicate setae. The arrangement of the
transverse rows is seen in figure. The lamina labialis (fig. 14 c)
seems to be represented by two rounded structures meeting in the
middle; in front of it the two usual rows of setae are found. The
arraugement of the hairs behind and between the serrula 6-dentata
is seen in figure. In the middle between the labial lobes a large
group of densely placed hairs is found, which laterally is continued
into an inner marginal row of longer and a more lateral row of
shorter hairs. Independent of these, and more laterally, two rows
of short setae are found.

fc?. Size of male from Thor St. 82 was 5-24 mm.; anterior
division 3-93 mm.; urosome 1-31 mm. Th. Scott's specimens measured
c. 4 mm., Giesbrecht's 4-5, Esterly's 5-3 and A.Scott's 4-4 mm.

The shape of the body is somewhat more slender than in
the female. The rostrum is more slender than that of the female,
and its branches have sometimes a delicate terminal filament. The
fifth thoracic tergite is fairly well marked in front, and is distinctly
rounded (text-fig. 69 a).

The abdomen, which is about one third of the anterior di-
vision, has on the left side of the first somite a backwards directed, rather prominent process, in which
the genital opening is found; a fairly distinct serrated seam was found along the hinder margin of the
second to the fourth somites.

The antennulae extend to the end of the fourth abdominal somite, and are almost straight.

Segments 8~9 to 13 are more or less fused, but the articular membranes between segments 80.9 and

10, and between 12 and 13, are fairly well developed anteriorly; the segments 21 and 22 are fused on

the right side, while segments 24 and 25 are well separated on both sides. The articulation between

segments 14 and 15 is only poorly developed. Most of the bristles are soft-skinned, and very much

like sensory setae. One or two ".^stheta.sken" were found in all segments from 1-19; a proximal seta

28

The Iiigolf-Expedition. III. 4-

Text-fig. 69. ScoUocalanus Thorii n. sp. f d-
a. .■\bdomeii X i5- b. Pes V dext. from
the left and partly from below X 59-
c. Re III dext. from below, d. Pes V
sin. Re III from the right side.

2l8

COPEPODA

was found iu segments 12 and 14, but not in segment 18. The Sp. of segment 24 does not extend to
the end of segment 25. The segments 8—12 are 1-4 as long as segments 23—25, and segment 19 is i-i
as long as 23. The antennae, mandibulae and maxillulae are practically like those of the adult females.
The sensory organs of the maxillae are better developed, and the maxilUpeds show the usual differences.
The nafatory tegs are scarcely different from those of the females.

The. Ji/ih pair of legs is distinctly longer than the abdomen. The rig/if leg (text-fig. 69 b) has
the third basipodite rounded in the usual way; inwards a short process is found, where the endopodite
is articulated; this extends distinctly beyond the end of the first outer segment, is gradually attenuated,
distally curved and here slightly hollowed. The first outer segment has several projections medially,
and is distinctly produced inwards terminally, where is the outwards convex second segment, with a
shallow excavation facing forwards and inwards; the third segment is short and somewhat attenuated
(text-fig. 69 c).

The basipodites of the le/t leg are, as usual, long and slender; the endopodite, which extends

somewhat beyond the first outer segment, is a thin, elongated
structure with indication of segmentation in the middle, some-
what enlarged terminally, and with a small terminal seta. The
left exopodite consists of two segments of almost equal length;
the second is somewhat enlarged, and is terminated with 2 — 3
leaf-like structures in addition to a slender hook-shaped organ
dissolved into "setae" terminally, and a plate with at least 7 long
serrations (text-fig. 69 d and PI. VIII figs 14 a — b).

The labrum etc. are in all features of interest like those
of the female; a curious feature was, however, found in the
arrangement of the hairs on the anterior surface, as the oblique
row of hairs between the two convex rows was wanting.

Text-fig. 70. Scottocalamis Thorii n. sp.

a. YQ (St. Vl. Head X 33- b Abdomen X 33-

c. Pes V in post, view X 59- d. Ycf (St. V).

Pes V X 59-

Y ^ (St. V). Size of female from Thor St 88 was 3-84 mm. ;
anterior division 3-06 mm ; urosome 078 mm. Male from St 82 measured 3-63 mm.

The shape of the body (text-figs 70 a— b) is in the main like that of the adult female, but the
frontal keel is just indicated; the fifth thoracic somite is well marked in front, and its lateral corner
is produced into a short but distinct tooth. The abdomen consists of four somites, of which the second
is longer than the first and third, which are of equal length and longer than the fourth. The first
abdominal somite has a small process on the left side; the serrated membrane of the somites II — IV
is only indicated. The appendages are, with the exception of the fifth pair of legs, like those of the
adult females as well as alike in the two sexes. In the female (text-fig. 70 c) the fifth foot consists of
three distinct, almost square segments in addition to a short terminal one, produced into a short spine,
at the base of which an exterior delicate hair is found; at the base of the last segment a strong
spine is found, at least as long as the 3 distal segments. The fifth pair of the male consists of two
short basal segments iu addition to the undivided branches, somewhat asymmetrical (text-fig. 70 d).

Occurrence. The Ingolf Expedition has not gathered this species, but it was taken at the
following stations by the Thor.

COPEPODA

219

111 Denmark Strait

'9/6 1904 St. 152 65°oo L. N. 28°io h. W. Yt. 1000 M. Wire i f ?.

20/,

1904 St. 153 65°27 L.N. 27°i2 L.W. Yt.

If?.

In the Atlantic, south of Iceland

Vq 1904 St. 285 62°49 L. N. i8°46 L.W. 3 fd", i f?-

1% 1904 St. 180 6i°34 L. N. i9°o5 L.W. Yt. 1800 M. Wire i f$.
•■/; 1904 St. 183 6i"3o L. N. i7°o8 L.W. Yt. 1800 M. Wire 2 f?.

25/5 1904 St. 104 62°47 L- N. i5°o3 L. W.

2 f?, I fc?.

In the Iceland-Fseroe channel

29

29

8 1905 St. 164 6i°20 L. N. ii°oo L.W. Yt. 300 M. Wire i fc?.

Is 1905 St. 165 6o°oo L. N. io°35 L. W. Yt.

I f?, I f<?.

"/5 1904 St. 99 6i°i5 L. N. 9°35 L.W. Yt. 1700 M. Wire i fc?.
■2/5 1904 vSt. 78 6i°o7 L.N. 9°30 L.W. if?.

Outside the Ingolf area

'5/6 1905 St. 82 5i°32 L. N. i2°03 L.W^ Yt. 800 M. Wire i f?, i y? (V).

Yt. 1200 M. Wire 10 f?, i fc?, 2 yc? (V).

Vo 1905 St. 167 57°46 L. N. 9°35 L. W. Yt. 1500 M. Wire 6 f ?, i yd* (V).

% 1905 St. 72 57°52 L.N. 9°53 L.W. Yt. 1500 M. Wire 5!?, 9 f c?.

20/6 1905 St. 88 48°09 L. N. 8=30 L. W. Yt. 300 M. Wire i f c?, 3 y ? (V).

Distribution. This species is by Farran recorded as fairly common on the west coast of Ire-
land "at depths of from 330 to 1150 fathoms"; it has been recorded by the Monaco Expedition, and
from the gulf of Guinea. The records from the South Atlantic, the Pacific and the Indian Ocean cannot
be accepted.

Remarks. That the species is identical with the male of Sc. se.curifrons Scott and with Farran's
S. persecans seems not to be doubtful. I think, that Farran, in contrast to Sars, is right in apply-
ing the name Sc. securifrons to the species with the pointed lateral corner, as Canu, who was the
first to rediscover the species, has done so. Farran has identified the Atlantic species with Gies-
brecht's S. persecans, and, as will be .seen in the nomenclature of Plate VI, I once thought he
was right. But on full consideration I feel obliged to follow A. Scott, and admit that S. persecans is
another species, and I have accordingly given the Atlantic species the name 5. rhorii in appreciation
of the good work of this expedition. The female of .5". persecans has been only imperfectly described
by Ester h-, but the fifth foot seems to be somewhat different. The male of S. persecans is charac-
terized "b\- the moderately long spines on the rami of the rostrum", and by several structures in the

structure of the fifth foot.

28*

220

COPEPODA

70. Scottocalanus securifrons Th. Scott.
(PI. VIII figs 13 a — b; text-figs." 71 a— d, 72 a— e and 73a-d.)

1893. 9 nee. d- Scolecithrix secvirifroiis 11. sp. Th. Scott pp.

47-48, pi. IV- V.
1896. Scolecithrix securifrons Scott. Canu, p. 425.
1898. - — — Giesbr. & Schmeil, p. 49.

1903. pars. — — — Norman, p. 137.

1903. — — — J. C. Thompson, pp. 20— 21.
1904.? — — — Cleve, p. 197.

1904. Lophothrix — n. sp. Wolfenden, p. 120, pi. IX

figs 12—15.

1905. Scottocalanus acutus a. sp. G. O. Sars, p. 7.
igo6. ? pars. — securifrons Scott. Pearson, p. 19.

1908. — — — Farrau, p. 57.

190S. 9 nee. o" Scolecithrix securifrons Scott, v. Bremen, p. 76

fig. 88.

1909. Scottocalanus securifrons Scott. A. Scott, pp. 104 — 105

pi. XXV figs 1-9, pi. XXVIII figs 1—9.
191 1, pars. Lophothrix securifrons Scott Wolfenden, p. 268.

Description. f$. Size of female from Thor .St. 82 was 449 mm. ; anterior division (to the end
of the lateral corners) 377 mm.; nrosome 072 mm. Th. Scott's specimens measured 4 mm. and
A. Scott's 4-3 mm.

The crista is scarcely different from that of the preceding species, bnt the lateral corners are

triangularly produced into spine-like
processes, which in dorsal view are
seen to be directed somewhat outwards
(text-figs 71 a— b). The rostrum has
the basal portion elongate, with paral-
lel margins; the divergent rami are
short, without distinct tooth. The ge-
nital somite is strongly swollen below,
and it is distally produced into a strong
process which overlaps the proximal
half of the following somite. Along
the hinder margin of somites II — IV
a generally well developed serrated
seam is observed (text-figs 71 a— b).
The antenmilar are like those of the preceding species, but the articular membrane between
segments %'^<^ and 10 are wanting posteriorly, and segments Sc^g have only one sensory seta (text-fig.
71 d). The oral appendages are scarcely different from those of the preceding species.

The natatory legs are very similar to those of the preceding species, but the outer spines of
the second basipodite, as well as the inner of the third one, are comparatively longer in the second and
third pairs of legs. The second basipodite of the first pair of legs has anteriorly and outwards near
the end a rounded broad process; the Se of Re I is comparatively longer. The Se of Re I in the
second foot is di.stinctly pointed. "V^^ fifth pair of legs is shorter; the inner process is longer, and its
spine is longer and stronger; the outer spine is much shorter, as it does not reach the end of the
genital somite, and the inner serration consists of fewer teeth.

The structure of the labntvi etc. is scarcely different from that of the preceding species,
fc?. Size of male from Thor St. 82 was 4-98 mm. ; anterior division 381 mm.; nrosome 1-17 mm.;
Scott's specimens measured 475 mm.

Text-fig. 71. Scottocalamis securifrons Th. Scott f9.
-b. .'Abdomen X 15. e. Genital somite from below X 46.
d. Segments VII— X of the autennulae.

COPEPODA

221

The rosfruiii has the basal portion lono; and rather slender, and is divided into two rather short
branches, which each possesses a ver)- short tooth; the whole structure is completely like Scott's
fig. 4, PI. XXVII. The crista is scarcely different from that of the female. The fifth thoracic tergite
has near the dorsal margin a distinct slender tooth, almost reaching the middle of the first genital somite.
The abdomen (text-fig. 72 a) is like that of the preceding species, but the lateral process of the first genital
somite is less prominent. The antenmilac as well as the oral appendages are scarcely different from
those of S. Thorii (text-fig. 72 b); the natatory legs do not differ from those of the females. The right
endopodite of pes V (text-fig. 72 c) is very short, and consists of three segments, which are indistinctly
separated; the second segment is the longest, and the third one is a short conical process bearing a
slender seta. The first outer segment is long, and distinctly widened out terminally, where it medially
possesses 3 expansions anteriorly and a single more prominent outer one posteriorly; the second outer
segment is comparatively short, and, outwards,
convex with a terminal expansion, and the third
one is short, rounded, with a single spine. The
described terminal parts of the right exopodite
form a clasping organ (text-fig. 72 c— d). The
two cylindric basal segments of tlie left leg
(text-fig. 72 e) have each a basal rounded process
as seen in figure; the third basipodite has an
inner terminal one as well. The left endopodite
consists of two segments, of which the one is
rather short and rounded with distal process,
while the other has two diverging processes,
of which the one is axeshaped. The left exo-
podite consists of a short basal segment and
a longer distal one, inwards excavated and
enlarged towards end ; the inner margin of
this is terminally and posteriorly densely spinous,

and anteriorh- a laminous process divided into two spines is found. The third segments consists of a
rounded basal portion with a few teeth, and a much longer pointed spinelike portion (PI. \'III figs
13 a-b).

y| (St. V). Size of female from Thor St. 82 was 3-45 mm.; anterior division 280; urosome 0.65
mm. Size of female from St. 90 was 3-54 mm.

The frontal keel is less prominent than m the adult, though distinct. The lateral corner is
produced into a distinct tooth (text-figs 73 a— e). The fifth foot of the female is much shorter than in
the preceding species; the limitation between the segments is more indistinct, the third outer segment
is only represented by a short spine, and the inner spine is not as long as the three terminal segments
(text-figs 73 c— d). The fifth foot of the male is characterized by a short, distinct spine in the left exo-
podite as well as by the pointed endopodite; the brandies of the right side, especially the endopodite,
are distincth- more rounded.

Text-fig. 72. Scottocalanus securifrons Th. Scott itS.
Abdomen X '5 b. Segments VII— XIV of the left antennula
51. c. Pe.s V dext. X 33- d. Pes V dext. Re IX — III in right
view. e. Pes V sin. two first segments in dorsal view.

222

COPEPODA

Occurrence. In the Atlantic, south of Iceland, the Thor has gathered this species.

9/y 1904 St 178 63°o8 L. N. 2i°30 L. W. Yt. 750 M. Wire i f ?.
"/; 1904 St. 183 6i°30 L. N. i9°05 L. W. Yt. 750 M. Wire i f?.
^-Vj 1904 St. 104 62°47 L. N. i5°03 L. W. Yt. 1800 M. Wire i f?.

In the Iceland-Faeroe Channel:

^9/8 1905 St. 164 6i°20 L. N. ii°oo L. W. Yt. 300 M. Wire 2 f?.

Outside the Ingolf area:

•V6 1905 St. 82 3i°32 L. N. i2°o3 L. W. Yt. 800 M. Wire i f d*.

Yt. 1200 M. Wire 18 f?, 5 f <?, 3 y$ (V).
8/6 1905 St. 72 57°52 L. N. 9°53 L. W. Yt. 1500 M. Wire i f ?.
^% 1905 SL 88 48°09 L. N. 8=30 L. W. Yt. 300 M. Wire 3 f?, 8 fc?, i y? (V).
"/e 1905 St. 90 47°47 L. N. 8°oo L. W. Yt. 300 M. Wire 4 f?, 7 fd", i y? (V), i vc? (V).

Distribution. This species is, according to Far ran, very
characteristic of deep-water tow-nettings off the west coast of Ire-
land, most plentifully at about 700 fathoms, but it was taken at
100 fathoms. It has been recorded from the Bay of Biscay b}-
the Monaco Expedition, from the Gulf of Guinea, and by Wolf-
en den in the Atlantic as far south as 35° L. S. By A. Scott it
has been recorded from the Malay Archipelago.

Remarks. As this species (males, females, adult as well as
young ones) is distinguished from the preceding species by a
number of important characters, viz. pointed lateral corners aud
the structure of the fifth foot, Wolf end en is certainly wrong in
regarding Scott, acutus G. O. S a r s and Sc. securi/rons T h. Scott
(Sars) as the same species. The species, which A. Scott has

described from the Malayan Seas and referred to this species, seems in all essentials to be like the

Atlantic form.

Text-fig. 73. Scottocalaniis securifrons Th. Scott
a — b. Y9 (St. V). Head and first abdomiual
somites X 33. c. Y9 (St. V), Pes V dext.
in posterior view X 59. d. Y cf (St. V). Pes
V X59-

Phaennidae.

71. Cornucalanus chelifer Thomps.
(PI. VII figs 4 a— h, PI. VIII figs 15 a— g).

7903? Scolecithrix chelifer n.sp. J. C. Thompson, pp. 21—22, 1907. Cornucalanus chehfer Thomps. G. O. Sars, p. 27.

pi. V figs 1-9. 190S. — — — Farran, pp. 49-50.

i9°,'i. — — — Farran, p. 36, pi. VII figs I igo.S. Onchocalanus chelifer Thomps. v. Bremen, pp. 65 - 66.

18 — 19. ' fig- 76.

1905. Cornucalanusmagnusn.sp. Wolfenden,pp.2i — 22,pl.VII. I 1911. Cornucalanus magnus Wolf. Wolfenden, pp. 281— 83, pi.

1906. Onchocalanus chelifer Thomps. Pearson, p. 19. ! XXXII figs i — 10, text-fig. 45.

COPEPODA 22^

Description, f?. Size of female from Thor St. 183 was 87 mm; anterior division 67 mm.; uro-
some 2 mm. Wolfenden's specimens measured 8mm.

The head has a low terminal crista with a dorsal spine directed forwards and downwards (PI.
VIII fig. 15 a). The rostrum is bifurcate with the spines directed downwards and backwards, each
bearing terminally a slender backwards curved filament. The shape of the body is like Wolfenden's
figure; the articulation between the head and first thoracic tergite, as well as between the fourth and
fifth tergites is well developed; the lateral corners are .somewhat triangularly produced, are rounded
and possess a small tooth (PI. VII fig. 4 a).

The abdoHtcit, which is about one third as long as the anterior division, has a serrated seam
along the hinder margin of somites II — IV; the somites, especially the genital one, are all over covered
with short hairs or spines. The genital somite, which is a little longer than deep, is distinctly pro-
duced below; the receptaculum seminis is, as seen in fig. 4a, well developed. The fifth abdominal
somite is scarcely visible from above, the comparative length between the three first somites and the
furcal branches, which are wider than long, is 35, 22, 17 and 10. The St 2, at the base of which a
dorsal tooth is seen, is almost half as long as the body and twice as long as the other setae.

The antennulae, which scarcely extend to the end of the cephalo-thorax, consist of 24 segments,
"..^sthetasken" are found in segments 2, 3, 5, 7, 9, 12, 14, 19 and 25, as well as in segments 18 and 21,
but here representing the distal seta. A proximal seta was found in segment 12 as well as in segments
14—18. The Sp. of segment 23 is well removed from the tip of segment ('/^ — ■/, of its length), and
extends scarcely to the end of segment 25. The segment 21 is 1-3 as long as segment 22.

The endopodite of the antennae is two thirds as long as the exopodite; its second segment has
8 setae in the inner lobe and 6 in the outer lobe. The manducatory part of the inandibjtlae is long
and slender, with fairly well developed teeth; the third basipodite, which is about as long as wide,
has three setae inwards; the second segment of the endopodite has 9 Sp.

The Lob I of the niaxillulae is long and slender; the Li 2 has two long plumous setae, the
Li 3 has 4 setae, and the third basipodite has 4 Sa and i Sp. The Ri I has 3 setae, the Ri II has 3,
of which one is ver)' delicate, and the Ri III has 4 setae. The exopodite has 10 setae and two groups
of short spines on the anterior surface; the Le has 7 + 2 setae.

The viaxillae and viaxillipcds have a very characteristic structure, but are scarcely different
from Wolfenden's figure.

The first pair of legs is like Wolfenden's figure; the segments are broad, and the exopodite
has 3 segments with powerful outer setae; the endopodite has 3 fairly long spines on the posterior
surface; the exopodite has on the posterior surface of Re II at the base of Si five slender spines, and at
the base of Si I Re III two spines. A glandular pore is found beyond the middle in the outer margin
of Re in. The second pair of legs is like Wolfenden's figure, but the segments are comparatively
longer; the first inner segment is produced into a fairh- long, somewhat rounded, spine; the armature
of the posterior surface is scarcely different from Wolfenden's description. The St has the serrations
almost completely fused in the distal three fourths, but only fused in the middle in the proximal fourth,
leaving a basal fenestra free. Small glandular pores were found at the base of Se Re I and II, and
at the base of vSe 1 and 3 of Re III. The fliird pair of legs is in main features like the: /ourt/i pair;

224 COPEPODA

the number of glandular pores is like that of the second foot. T\\e^ /onrf/i foot is like Wolfenden's
fio-ure, but the armature of the posterior surface of the third outer segment differs in minor details
(PI. VII fig. 4 b); the structure of the St. is like that of the second foot (PI. VIII fig. 15 b). 'l\\^ fifth
pair of legs (fig. 4c) consists of three segments, bearing a few hairs posteriorly; the terminal segment
is rather slender, attenuated, and produced into a rather short terminal spine.

The lateral outline of the labruin etc. is rather characteristic, as seen in fig. 15 a; a well devel-
oped epistoina densely covered with about 40 long setae on each side was found; the hibrum proper
is denselv covered with setae, the arrangement of which is similar to that seen in fig. 5 e, though
differing in details; anteriorly a group of rather short setae (about 3 deep) is found; this group is on
each side continued into a large group of long setae, placed laterally and posteriorly, extending towards
the hinder margin, where groups of shorter setae are found. In the area in front of the mentioned
groups a median group of fairly long setae is observed.

The oral surface of the labrum (fig. 4 d) is rather characteristic. Laterally, in front, an almost
transverse row of rather short setae is found; behind this a longitudinal row of setae is observed. In
the middle, on each side, 3—4 almost completely fused groups of densely placed, fairly long, setae are
found. In the middle, around the median circular spots, areas of short spines or granules are found.
The lamina labialis seems to be wanting, but the serrula 6-dentata is well developed (PI. VII fig. 4e);
in front, a median wide and elongated group of fairly long setae is found, as well as a lateral rounded
one. Between the serrulae and behind, 2 groups of setae are found. TJie arrangement of the densely
placed hairs on the labial lobes and on the area behind was not studied in details, but shows great
similarity to that of O. magniis (fig. 5 e).

f c^. Size of male was 6'i7 mm.; anterior division 4-95 mm.; urosome 1-22 mm.

The head is rounded, without any frontal crista or spine (fig. 15 d). The rostrum is strong, with
short terminal filaments. The lateral corners are rounded, without any spine (PI. VII fig. 4 f).

The abdomen is only one fourth as long as the anterior division; along the hinder margin of
somites II — IV a marginal serrated seam is found; the fifth abdominal somite is almost rudimentary; the
comparative length of the first four abdominal somites and the f ureal branches is 8, 20, 15, 10 and 5.

The antennulae extend to the end of the cephalo-thorax; the two first segments are inflated
and much more powerful than those following; they contain 24 segments, but the articulation between
8'>'9 and 10 and between 12 and 13 is wanting posteriorly, "^sthetasken" are found in the following
numbers, i in segment i, 4 in segment 2, 2 in segments 3—8^59, and a single one in segments 10 — 19,
22 and 25. The mensurements are scarcely different from those of the females. The antennae are like
those of the female, while the niandibulac differ from those of the female by the much wider third
basipodite with three short setae medially.

The iiiaxilhilae differ from those of the female by the rudimentary setae of the Li I and the
two short setae of Li II. The maxillae are very similar to those of O. cristatus (PL VII fig. 6 c), but
the spine of lob. IV is comparatively stronger, being longer, though less powerful, than that of lob. V;
the number of the setae is scarcely different from that of the female; the sensory setae of the endo-
podite have a rather curious structure, with a more or less prominent, rather short, terminal filament
surrounded by short delicate dentations. The luaxillipeds are wideh- different from those of the females,

COPEPODA

225

especially on accouut of the wanting strong spines of the endopodite; the dentation of the third basi-
podite is not better developed than in related species; the fourth lobe of the second basipodite has
two short setae in addition to the spine.

The natatory legs are scarcely different from those of the female. The fiftli pair of legs is not
unlike Wo 1 fen den's description, but his right foot corresponds to the left one in my specimens (PI.
VII figs 4f— g). The right foot (fig. 156) consists only of three segments and a short terminal tooth.
The left leg consists of 5 long proximal segments, in addition to a fairly short, attenuated and hairy
third outer segment, which has a short terminal seta (fig. 4g).

Yq (St. V). Size of female from Thor vSt. 183 was 6-3 mm.; anterior division 5-1 mm.; uro.some
1-2 mm. Size of male 64 mm.

The shape of the body is like that of the adult female, but the lateral corner is more pointed
(fig. 15 f); the abdomen consists of four somites, the comparative length of which was to, 19, 14, 8
and 5. The appendages, except the fifth feet, are in the young female like those of the adult females
(PI. \'II fig. 4 h), this pair is even less developed than that of the adult, as seen in the drawing; in the
male each leg consists of four segments, and the left leg is considerably longer than the right one; about
the arrangement of hairs and setae I refer to fig. 15 g.

Occurrence. The Thor has in Denmark Strait once gathered this .species viz:

19/6 1904 St. 152 65°oo L. N. 28°io L. W. Yt. 200 M. Wire i f?.

In the Atlantic, south of Iceland:

'% 1904 St. 180 6i°34 L. N. i9°05 L. W. Yt. 1800 M. Wire i f?, i fc?.

"/; 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 31 f?, 6 fd", 3 y? (V), 4 yc? (V).

In the Iceland-Fseroe Channel:

'Vs 1904 St. 78 6i°07 L. N. 9°30 L. W. 3 f?.

In the Atlantic, south west of the Fseroes:

76 1905 St. 72 57^52 L.N. 9°53 Iv. W. Yt. 1500 M. Wire 4 f?.

Distribution. According to Farran "this species is of frequent occurrence in deep-water tow-
nettings off the west coast of Ireland", at depths of from 330 to 1150 fathoms. By the Gauss it was
taken 9/,o near the Cape Verde Islands, and '^/u it was taken about 35° L. S. 0-5° L. E.

Remarks. In spite of minor differences I do not doubt that this species is identical with Cor-
nucalauus )uagnus Wolf.; Wolfenden refers Thompson's Sc. die lifer to a different species on account
of a wanting frontal spine; as Thompson's description of a young male is so very imperfect, I prefer
to follow Farran and Pearson.

72. Onchocalanus magnus Wolfenden.
(PL VII figs 5a-g; PL VIII figs 16 a— d).

1906? Xantliocalanu.s magnus n. sp. Wolfenden, pp. 32 — 33,

pi. X,
1908? — — Wolf. Wolfenden, p. 37, pi.

Onchocalanus frigidus n. sp. Wolfenden, pp. 276

—277.
nee. — magnus Wolf. Wolfenden, pp. 275

VII figs 1—9. I -276, pi. XXX.

'I'lie Iiigolf-Expedition, III. 4, ^

226 COPEPODA

Description. Size of female from Thor St. 183 was 8-3 mm.; anterior division 6-5 mm.; urosome
I-8 mm. Wolfenden's specimens measured 8-8 mm.

The body is rather elongated; the head (fig. 5a) is well raised, with distinct eyes, but without
trace of frontal keel or spine. The rostrum (PI. VIII fig. 16 a) is bifurcate, with fairly long, slightly
divergent spines, one of which, at least, possesses a slender filament. The lateral corner is triangularly
produced, and has a well marked pointed tooth, which in some specimens, however, is only indicated,
but is generally most distinct on the right side.

The abdovioi (PI. VII fig. 5b) is scarcely one third as long as the anterior division; the genital
somite is rather suddenly produced below; the genital opening is more broad than long, and is placed
in the middle of a densely hirsute area ; the lateral margins are somewhat overlapping and pointed in
front; an elongated receptaculum seminis is found. The anal somite is scarcely visible from above; the
comparative length of the three first abdominal somites and the furcal branches is 32, 22, 16 and 11.
The marginal serrated seam along the hinder margin of segments 2 — 4 is only poorly developed.

The somites are more or less hirsute, especially ventrally; the first somite has the hairs more
distinct, especially dorsally in front, where a pad of densely placed hairs is found.

The antennulae reach almost to the end of the body and consist of 24 segments the appendages
are scarcely different from tliose of C. chelifer\ the Sp. of segment 24 is one third removed from the
end of the segment, and is far from reaching the tip of the segment 25. The segments 21 and 22 are
of almost equal length. The exopodite and the endopodite of the antennae are of almost equal length ;
the mandibulae and maxillulae are in main features like those of C. chelifer. The basipodite of the
maxillae is first strongly excavated and then distinctly produced; the lobe i has 5 setae, the lobes
2 — 4 have 3 setae ; the posterior seta of the fourth lobe is stronger than the preceding setae, but much
weaker than the strong curved spine of the fifth lobe, at the base of which 3 fairly long and slender
setae are found. The endopodite has 6 brush-shaped sensory organs in addition to a long slender one.
The inaxillipeds show great similarity to those of C. chelifer; the comparative length between the
main divisions is 18, 29 and 15. The first and second basipodites are like those of C. chelifer] the third
basipodite is about 6 times as long as wide, with the three proximal setae well separated from each other;
and inwards and basally with an area of densely placed delicate spines. The second segment of the endo-
podite has one short serrated curved spine and two long ones; the third segment has two similar spines.

The first pair of legs is like that of the preceding species, but the segments are much more
slender. The second pair of legs is like those of the preceding species, but is distinctly more slender;
the third outer segment is about twice as long as wide, and as long as the terminal spine. The outer
spine of the first inner segment is fairly long and somewhat obtuse; on the anterior surface of the second
inner segment^a small pore surrounded by slender hairs is found ; indistinct glandular pores were only
found in Re II and at the base of Se 3 Re III. On the posterior surface of the two inner segments
coronas of spines were found, while larger and smaller prickles were found in numbers in the outer
segments. The third pair of legs differs from the following pair by the comparatively longer and
thicker teeth, especially in the endopodite. The fourth pair of legs has marginal setae in the second
basipodite; a glandular pore is observed in the second outer segment; the posterior surface is covered
with groups of short prickles or fairly long setae, with all intermediary steps between; the setae are

COPEPODA

227

comparatively shorter in the two outer segments. Anteriorly, hairs are only found in the second basi-
podite, where, f. inst., laterally a large group of long setae is found.

The fifth pair of legs (fig. 5 d) consists of three segments ; the exopodite has a terminal and two
outer spines ; the anterior surface is almost smooth, while the posterior surface as well as the sides
are covered with long setae.

In front of the rather prominent labruni proper a prominent episfoiiia (PI. VII fig. 5 a), which is
densely covered with long bristles (fig. 5e), is found; the bristles of the labrum are neatly arranged into two
anterior groups of long bristles, about three lateral groups of shorter hairs and a single marginal row.
The oral surface of the labrum (fig. 5 f) is anteriorly densely covered with a number of short minute
prickles; scarcely distinguished from these, two lateral groups of hairs are found, probably corresponding
to two groups in C. cJielifer. Almost in the middle, on each side, about three almost completely fused
groups of short bristles as seen in figure are found, and more behind, an oblique group of delicate
hairs is found. In the middle densely placed granules are found in transverse areas. No distinct
lamina labialis is found; in front of the serrula 6-dentata (fig. 5 g) a large inner group of short granules
is found, and an outer longitudinal row of fairly long hairs. Behind, a horse-shoe shaped group of
granules is found on each side and, well separated from this, as seen in fig. 5 e, irregularly placed short
hairs. Along the inner margin of the labial lobes inwards short spines, and more outwards long bristles,
are found.

Y^ (St. V). Size of female from Thor St. 183 was 6-25 mm.; anterior division 5 mm.; urosome
1-25 mm.

The shape of the body is scarcely different from that of the adult, but for the regularly pointed
lateral corner. The comparative length of the four abdominal somites and the furcal branches is 10,
15, 13, 8 and 6. The abdominal somites are almost completely smooth. But for the comparatively
shorter fifth foot, the appendages are scarcely different from those of the adult females.

Occurrence. The Thor has taken this species at two stations.

"/^ 1904 St. 183 6i°3o L. N. 17^08 L. W. Yt. 1800 M. Wire 2 f?, 2 y? (V).
76 1905 St. 72 57°52 L. N. 9°35 L. W. Yt. 1500 M. Wire i y? (V).

Distribution. This species has previously been found in the Antarctic Seas.

Wolfenden has originally given the name X.?nagnns to a species about 8-8 mm. long with
pointed lateral corners. Later on he has subdivided his original species into a smaller one with rounded
lateral corners to which he applies the name O. viagnns, and a larger one which he names O.frigidus.
I think the name tnagmis must necessarily be used for the bigger species.

I am very doubtful, if my North Atlantic species is really identical with the Antarctic one; Wolf-
en den's description, however, is in several important points too incomplete to settle the question.

The differences are the following. In my specimens the first as well as the fifth thoracic
somites are well marked in front; the genital somite is not as long as the following three somites,
the vulva has no "lateral flap" on each side, and the genital somite can scarcely be called "very swollen

ventrally". The anteunulae are longer, as they reach distinctly beyond the middle of the genital

29*

228

COPEPODA

somite. The Li 2 of the inaxilhilae has 2 not 3 setae. The Ri 2 of the fourth foot has no "corona of
spines", but a number of fairly long bristles, and the fifth feet seem to be somewhat different.

73. Onchocalanus cristatus Wolf.
(PI. VII figs 6 a— e; PL VIII figs 17 a— f).

1904. Xaiithocalauu.s cristatus n. sp. Wolfeiulen, p. i ig, pi.

IX figs 18-19.

1905. Onchocalanus trigouiceps n. sp. G. O. Sars, p. 20.

1906. Xanthocalanus cristatus Wolf. Pearson, p. 20.

1906? — siniilis n. sp. Ksterh\ pp. 68 — 69, pis 9 13.

1907. Onchocalanus cristatus Wolf. G. O. Sars, p. 3.

1908. Onchocalanus cristatus Wolf. Farran, p. 49.
1908. Xanthocalanus cristatus Wolf 'W'olfenden, p. 34.
1908. — — — V. Bremen, p. 62 fig. 70

1909? Onchocalanus cristatus Wolf. A. Scott, pp. 82 — 83, pi.

XXXIV figs I -8.
191 1. — — — Wolfeniien, pp. 277 — 278.

Description. f$. Size of female from Thor St. 183 was 8-15 mm.; anterior division 6-45 mm.;
urosome 170. Another specimen measured 7-5 mm. Wolfenden's specimen measured 5-5 mm., Sars's
7 nnn. and Scott's 6-6 mm.

The shape of the body is like that of O. iiiagi/iis\, but it is more slender; the first as well as
the fifth thoracic .somite is well marked out in front. The liead (PI. VIII fig. 17 a) is well raised, and
surmounted with a dorsal low crest, visible in dorsal as well as in lateral view. The rostrum consists
of a basal portion and two fairly long somewhat divergent spines without distinct terminal filament.
The lateral corners are triangularh' produced and terminated with a distinct tooth.

The abdomen is a little more than one fourth as long as the anterior division ; the genital
somite is like that of O. i/iagiiiis, but is less produced below. The comparative length of the abdominal
somites and the furcal branches is 28, 18, 13 and 6; the somites are hair\' in a similar way as in
the other species.

The anfeiiJiiilac are like those of O. iiiagi/iis^ and extend about to the end of the furca; the
only difference is found in the slightly different measurements of the segment 13, whicli is 1-24 (not
i'4) as long as segment 12, and of segment 24 which is i-i as long as segment 23 (not a little shorter).
The antcnuat\ mandibulae and maxilhilae are scarcely different from those of O. /iiagints. The maxillae
are like those of the preceding species; the endopodite possesses in addition to a short seta of usual
structure a long slender sensory seta and 5 fairly long ones, the slightly enlarged part of which is
more or less "brush-shaped". The inaxillipcds are like those of the preceding .species, but the third
outer segment has 4 instead of 3 strong curved spines. The first pair of legs differs only by rather
unimportant details in the armature of the posterior surface. The Se of the first inner segment is
long, slender, and distinctly pointed in the second pair of legs. The third as well as the fonrtli pair
of legs differs from O. iiiagi/Ks in the details of the arrangement of the hairs, and by the curiously
contorted terminal spine. The fi/t/i pair of legs consists of three segments, of which the third, attenuated
one, is longer than the second, but shorter than the two basal ones combined; it has, as seen in fig.
6 a PI. VII, a terminal and two outer spines. The anterior surface is smooth, while the sides as well
as the posterior surface are all over covered with fairly strong setae or spines.

The labrutn (PL VIII fig. 17 a) etc. are not in any features of great interest different from the
corresponding organs of the preceding species.

COPEPODA 229

f cf. Size of male was 6-5 nun.; anterior division 507 nmi. ; urosome 1-43 nun.

The body is more slender than in the female; the head shows trace of a crista, especially in
dorsal view. The lateral corners are rounded and possess a small, well marked tooth.

The abdomen is fairly slender (PI. VII fig. 6 b) and is, as seen in figure, be.set with hair\- .spots.
The comparative lengtli of the first four abdominal somites and the furcal branches is 25, 55, 45,
28 and 15.

The antcnnulac extend about to the end of the bod}-; the proximal 7 segments are more
powerful than in the female. The segments Sc^^g to 13 are posteriorly indistinctly separated, as the
articular membrane is sometimes missing; the segments 20 and 21 are, on the right side, partly fused;
the appendages are scarcely different from the male of C. chelifer. The anteiuiac scarcely differ from
those of the female, but the iiiaiidibnlac differ by the wide third basipodite with three rather short
inner setae; the maxillulac are more soft-skinned than in the female; the Li i has 8 short setae, but
the number of setae is in other respects like that of the female. Tlie maxillae (fig. 6 c) is a soft-skinned
organ of somewhat similar shape to that of the female; the number of setae in the lobes is seen in figure;
the endopodite has 7 sensory setae, differing from rather clumsy ones basalh- to more slender ones distally.

The inaxillipeds are distinctl\- more robust than in the females; the comparative length between
the main divisions is 34, 34 and 15, the setae of the second basipodite, especially the sensory one in
the middle, are less developed ; the strong curved setae of the endopodite are represented by rather
weak setae.

The natatory legs are scarcely different from those of the female. T\\e fi/t/t pair of legs extends
almost to the end of the abdomen. The liglit leg is much shorter than the two first segments in the
left leg (cf. PI. VII fig. 6b), and it forms an outward convexity; the outer margin of the second seg-
ment is slightly convex, and somewhat spinous; the third segment is indistinctly divided into two
parts, and has at least a terminal and an outer rather weak spine as well as a number of stiff hairs
terminally on the posterior surface. The le/t Irg has two long cylindric basal segments, of which the
distal one is much the longer; the second segment is convex outward.s, and here possesses terminally
about 7 stiff hairs. The exopodite consists of three segments, decreasing in length as well as in
thickness from the first towards the third; the third segment (PI. VIII fig. 17 e) is somewhat attenuated
and hairy, and is in possesion of a short terminal spine.

The cpistoina (PI. VIII fig. 17 c) is well developed, with two rows of long setae; the labrmn proper
has, anteriorly, a well developed projection, but is posteriorly rather soft-skinned, with undulated lines
in the chitin; anteriorly 2—4 rows of long bristles are found; posteriorly, rows of short bristles were
observed; the marginal row of hairs was apparently wanting. The oral surface of the labrum is not un-
like that of the female, but the granulation in front is wanting; three well separated lateral groups
of hairs were found on each side. In the middle, just behind the third median circular spot, a single
transverse group of short bristles was found. In front of a well developed serrida 6-dcntata with
short teeth, a median elongated group with two longitudinal rows and, laterally, a single convex row
were found. The labial lobes are well developed, with short marginal bristles; between the lobes a
small pointed process is found on each side.

2,o COPEPODA

Y$ (St. V). Size of female from Thor St. 183 was 6-15 mm.; anterior divi.sioii 4-9 mm.; urosome

1-25 mm.

The shape of the bodv is more slender than in the adult female. Short, but distinct rostral,
filaments were found in the examined specimen. The comparative length of the abdominal somites
and the f ureal branches is 30, 50, 40, 20 and 17; the somites are distinctly hirsute. Tlie appendages
do not show anv difference of importance, except the fifth pair of legs; this was in one specimen (St.
167) shorter than that of the adult female, and especially the last segment was less slender; in another,
however (St. 183) (fig. 17 f PI. VIII), the last segment was, as seen in figure, divided into two; as the
right and the left foot were almost quite alike, I am most disposed to regard this feature as an
abnormity and not as one characteristic of the male.

Y? (St. IV). Size of female from Thor St. 183 was 4-36 mm.; anterior division 344 mm.; uro-
some 0-92.

The comparative length of the abdominal somites and the furcal branches is 28, 40, 40 and 17.
The uiaxillulac have only 9 setae in the exopodite. The natatory legs show the usual differences, as
the Ri II — III and Re II — III are fused; the second to fourth pairs of legs have only 3 Se in the Re
II<NiIII. The fifth pair of legs (PI. YII 6 e) is rather short and clumsy, with the first outer .seta of
Re III rather indistinct.

Occurrence. The Thor has taken this species in Denmark Strait:
'9/6 1904 St 152 65°oo L. N. 28°io L. W. i f?.

In the Atlantic, south of Iceland :

'% 1904 St. 180 6i°34 L. N. i9°05 L. W. Yt. 1800 M. Wire i y? (V).

'V7 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire 3 f?, 5 f J", 2 y? (V), i y? (IV).

^Vs 1904 St. 99 6i°i5 L. N. 9=35 L. W. Yt. 1500 M. Wire i f $.

In the Iceland-Fseroe channel:

29/8 1904 St. 165 60^00 L. N. io°35 L. W. Yt. 1000 M. Wire i y?.
"/s 1904 St. 99 6i°i5 L. N. 9°35 L. W. Yt. 1700 M. Wire i f?; i y? (V).
■i/s 1904 St. 230 63°io L. N. 7°3i L. W. Yt. 1200 M. Wire i f?.

In the Atlantic, south west of the Fseroes:

9/6 1905 St. 72 57°52 L. N. 9°55 L. W. Yt. 1500 ^I. W^re 2 f?, 3 y? (V), 2 y? (IV).

Distribution. This species has previously been recorded from the North-East Atlantic and is,
according to Far ran, not uncommon off the west coast of Ireland "at depths of from 330 to 1150
fathoms"; the other records are rather doubtful.

Remarks. On full consideration I do not doubt that the females and males are rightly referred
to the same species.

My specimens differ from Wolf end en's original description by its much larger size, and by
the maxillae, which do not possess "seven short thick brush processes", and, from a note (1906 p. 32)
by the number of setae in the third basipodite and the endopodite of the maxillnlae. It differs from
Sars' O. trigoniceps by its size and the anteriorly well marked first thoracic tergite.

COPEPODA

231

It differs from Scott's species from the Mala}' Archipelago by the less slender fifth foot
without inner spine, and by the endopodite of the maxillae, which does not possess 6 strongl)- brush-
shaped setae.

This species is nearly related to Ester ly's X. sirnilis\ it differs, according to him, especially by
the four segments of the fifth pair of legs (PI. XIII fig. 77). As the only examined female (from the
Gulf of California), which is 6-5 mm. long, is a young one of the penultimate stage, I tliink, although
the fifth pair of legs is completely like the four-segmented one whicli I have examined of the same
stage (PL VIII fig. 17 f), that a more detailed description is needed of specimens from this region before
settling the question.

74. Onchocalanus hirtipes G. O. Sars.
(Text-figs 74 a — i).

1905. Onchocalanus hirtipes n. sp. G. O. Sars, p. 20.
1908. — — G. O. Sars. Farran, p. 49.

1909. Onchocalanus hirtipes G. O. Sars. A. Scott, p. 83, pi.

XXXIV figs 9 — 17.

Description. f$. Size of female from Thor St. 183 was 5-3 mm.; anterior division 40 mm.; uro-
some 1-3 mm. Sars' specimens measured 47 mm., Farran's 57 and Scott's 5 mm.

The body is moderately slender. The head is suddenly, but not very much, raised, and does
not possess any crista. The fairly long rostrum has two only slightly divergent spines, each possessing
a long, slender terminal filament. The first as well as the fifth thoracic tergites are well marked in
front; the lateral corners are somewhat triangularly produced, but rounded (text-fig. 74 a).

The abdomen is one third as long as the anterior division; the genital somite is strongly pro-
duced below, and has a short receptaculum; in dorsal view it is seen to be much broader somewhat
in front of the middle ; in front and in a less degree behind it becomes suddenly narrow. The serrated
seam along the hinder margin from the second to fourth somite is well developed. Short, stiff, scattered
hairs are found on each side of the genital somite, and tufts of fairly long hairs on the ventral surface
of the fifth somite.

The antennulac reach about to the end of the genital somite; the appendages are scarcely
different from those of C. chelifcr, except the Sp. of the segment 24, which is one tliird removed from the
tip of the .segment, and extends to the end of segment 25. The segment 13 is r6 as long as segment
12, and the segment 24 is a little longer than 23.

The exopodite and the endopodite of the antennae are of almost equal length; the Si of the
first basipodite is as in the preceding species short. The niandibulac and maxillulae are like those of
C.chelifer, but for the presence of 11 setae in the endopodite (5 in the Ri III) of the maxillulae. The
structure of the maxillae is like that of the two preceding species; the endopodite has, in addition to
a single vermiform seta, 7 rather curiously developed -'brush-shaped" setae, similar to those figured in
Scott's fig. 14 (PI. XXXIV). The maxillipeds are similar to those of the preceding species; the com-
parative length of its main divisions is 65, 80 and 47; the sensory setae of the second basipodite is
distinctly brush-shaped, and scarcely twice as long as wide on the left side, but on the right side it
is like that of other species; the number of curved setae in the endopodite is as in the preceding
species, but they are comparatively weaker.

232

COPEPODA

The. Jirst pair of legs is like that of the preceding species; the Se of the Re I extends some-
what beyond the end of the Re II. The endopodite has on its posterior surface 3 + 2 spines; the
exopodite has 5 spines at the base of Se Re I, 6 spines at the base of Si Re II, and near the inner
margin of Re III three groups consisting of 4, 3 and 3 spines. The endopodite of the second pair of legs
has a long pointed Se in the Re I; on the posterior surface of Ri I a group of 5 fairly strong spines is
found, and in Ri II two outer rows of 6 spines and an inner one of 8 weaker spines. The terminal seta,
which is like that of the preceding species, is as long as the third outer segment; on the posterior surface
of the third basipodite and the exopodite groups of rather short spines are found ; the number of glandular
pores is like that of O. iiiagn?!^. The armature of the posterior surface of the //lird pair of legs is like
that of the preceding species; the endopodite has 5 long spines in Ri I, a curved row of 7 long spines
and an inner group of about 20 setae in Ri II, and in Ri III groups of 5 strong and 12 short spines;

the exopodite has a number of short spines and
bristles. The third outer segment is, as shown in
text-fig. 73 b, curiously short, probably due to ac-
cident; a similar abnormal structure has been
described by Wolfenden in the fourth pair of legs
of the male of C. chclifer (191 1 p. 283). T\\& foiirfh
pair of legs has the armature somewhat less
developed, but the third outer segment was trans-
formed in a similar way. The terminal segments
of the third and fourth pairs of legs were only
examined on the left side, as they were wanting
on the right side.

Text-fig. 74. 0„clwcalanus hirUpcs G. O. Sars. n^^^ ^yy^ ^^^y ^j ^ (text-figS 74 C-e) COU-

a. f9. Genital somite X 33. b. f9. Pes III Re III X 59- c. £9. - ' * ^ & /t /

Pes V siu. d-e. f9. Pes V Re III sin. et dext. X 150. f. fd". sists of three segments, which are almost com-

Abdomen X 33- g- Maxilla sin. in ant. view X iS"- h- fd"- 1 . 1 .1 ^1 . • r , .

!>..„ ir :^ „„f ;<. N^ - : <-, T> ir • t> ttt plctely smooth on the anterior surface, but post-

Pes V in ant. view X 59. i- f d^- Pes V sm. Re III. ' •' ' '

eriorly at least in distal half of the segments, the)-
are covered with fairly long stiff hairs; the left leg has terminally a bifurcate process (fig. 74 d), and
in the right a three-divided one (fig. 74 e) is found.

The lateral view of the labriiiii etc. is like that of the preceding species; the organs were
not examined in detail in the single specimen at my disposal.

i$. Size of male from Thor St. 183 was 4-04 mm.; anterior division 3-05 mm.; urosome 0-99 mm.

The shajie of the cephalosome is scarcely different from that of the female (text-fig. 74 f). Th.e
abdomen has, as usual, five somites, but the fifth one is scarcely visible from above; the comparative
length of the four somites and the furcal branches, which are as long as wide is 25, 40, 33, 20 and
12. The distal segments of the antcntmlae were wanting; the proximal segments are like those of the
preceding species. The antennae^ tiiandihidae and inaxillulae show the same differences from those of
the female as in O. cristatus.

The maxillae are in general .shape like those of the preceding species (cf. PI. VII fig. 6 c); tlie
structure and arrangement of the 8 sensory setae in the endopodite are seen in text-fig. 74 g. The

COPEPODA 233

)naxillipcds are like those of the female; the comparative length of the main divisions is 55, 65 and
32; the endopodite is somewhat shorter, and its setae are less strong. The sensory seta of the second
basipodite is three to four times as long as wide, curved, and somewhat attenuated; it is thus well
distinguished from the short one of the female, as well as from the comparativel)- long and straight one
of the male in O. cristatus.

The Jirst pair of legs differs from that of the female by the want of spines on the posterior sur-
face of the Re I, and by three spines only in Ri. The second pair of legs is scarcely different from
that of the female. The fliird pair of legs is in main features like that of the female; the third outer
segment is of usual structure, and the armature of the posterior surface is like that of O. i/iagiins.
The foiirfh pair of legs was very defective.

The fifth pair of legs, like that of O. cr/sfah/s, consists of a short right leg extending
scarcely to the end of the first segment of the left side, and of a long and slender left leg, which
extends distinctly beyond the end of the abdomen (text-fig. 74 f) ; the right leg has, as seen in text-fig.
74 h, three fairly long and broad proximal segments in addition to a rudimentary terminal one, con-
tinued into a short spine. The left leg consists, as seen in figure, of five elongated segments like those
of O. cristatus\ the third outer segment is, however, as seen in text-fig. 74 i, less slender, and has in
addition to the terminal seta a distal outer one.

Occurrence. The Thor has taken a male and a female of this species '7? ^9^4 St. 183 6i°30
Iv. N. 17^08 L. W. Yt. 1800 M. Wire.

Distribution. Previously a single specimen (?) has been gathered by the Monaco St. 1849, 36°i7
L.N. 28°28 L. W. 0—3000 M., on the west coast of Ireland (55° L. N. 10° L. W. at 11 50 fathoms) and by
the Siboga at 3° L. S. 127° L. E.

Remarks. My specimens do not differ from Sars' short description, and agree with Farran's
specimens in the shape of the genital somite, but differ by the shape of the fifth pair of legs, which
is not "five-jointed" on the one .side. From Scott's figures they differ by minor points in the structure
of the anteunulae, but especially b\- the third segment of the fifth foot, which has a distal Se in ad-
dition to an undivided St; as, however, the fifth foot seems to vary from the one specimen to the
other, there is not at present sufficient justification for separating the two species from each other.

75. Onchocalanus affinis n. sp.

(Text-figs 75 a— e and 76 a— d).

Description, f?. Size of female from Thor St. 183 was 6-3 mm.; anterior division 5-09 mm.;
urosome 1-4 mm.

The body is somewhat more slender than in the preceding species. The head is more suddenly
raised; the basal portion, which is more powerful than in the preceding species, is directed more
downwards (text-fig. 75 a). The first and the fifth tergites are only indistinctly marked in front; the
lateral corners are triangularly produced and obtusely rounded.

The abdorucn (text-fig. 75 b) differs from that of the preceding species by the shape of the
genital somite; dorsally the somite, somewhat in front of the middle, is rather suddenly wider than

The Ingolf-Expedition. III. 4.

234

COPEPODA

more anteriorly, but posteriorly it is of almost equal width. The comparative length of the three first

abdominal somites and the furca is 75, 50, 30 and 22.

The antennulae reach at least to the end of the third abdominal somite; the Sp of segment 24

is one third removed from the tip of the segment, and is far from extending to the end of segment

25; in other respects the antennulae are like those of the preceding species. The oral appendages are

scarcely different from those of O. hirtipes\ the com-
parative length of the main divisions in the maxilli-
peds is 85, 100 and 57; the sensory seta of the second
basipodite is fairly long like that of O. cristatus.

The Jirst pair of legs differs from that of O. htrti-
pcs by the number of spines ; the endopodite has 4 spines^
the exopodite has no spines in Re I, 7 spines at the
base of Si Re II, and in Re III 3, 6 and 6 spines near
the inner margin. The number of spines on the posterior
surface in the second pair of legs is somewhat greater
than in O. hirtipcs\ the endopodite has in Ri II 8 +
" 6 -|- 12 spines. In the structure of the third a.nA fourfh

Text-fig. 75. Onchocalanus a/finis ii sp. iQ.

a. Rostrum X 18. b. Abdomen X 18. c Maxilla sin. in legs no difference from the preceding species was ob-
anterior view X 150. d^e. Pes V sin. et dext. X 59- ggrved. The _fi/i/i pair of legs (text-figs 75 d-e) differs

from that of the preceding species by the structure of the terminal spines of Re III; in the left leg
two terminal spines in addition to a Se were found; on the right side the Se is poorly developed, but
a fairly strong Si was found. The anterior surface is, as in O. hiriipes, almost completely smooth.

fc?. Size of male from Thor St. 180 was 5-19 mm. ; anterior division 4-1 mm.; urosome rog mm.

The shape of the body is like that of the preceding species; the lateral
corners are more rounded and less produced than in the female. The com-
parative length between the abdominal somites and the furcal branches is 30,
45, 36, 24, 2 and 15. The antennulae almost reach to the end of furca; they show
the usual differences from those of the female. The antennae, viandibulac and
maxillulae are scarcely different from those of the adult female. The maxillae
differ by the structure of some of the sensory setae of the endopodite (text-
figs 75 c). The maxillipeds are like those of the preceding species, but the
sensor}' seta is shorter than in the preceding species; the comparative length
of the main divisions is 75, 80 and 42. The natatory legs are scarcely different Text-fig. 76.

x , , r ii r 1 Onchocalanus afftiiis n. sp. fcf-

from those of the female. _ „ , •' , ' ,

a. Pes V X 18. b. Basal

The. Ji/th pair of legs (text-figs 76 a— b) is onlv in minor points dif- segments of pes V x 59-

c. Pes V Re III dext. in
terent from that of O. hiriipes\ the right leg extends somewhat beyond the posterior view x 150. d. Re

first segment of the other side. The terminal segment of the riglit leg is ^^^ ^'°- ^ '^o-

somewhat bigger than in the preceding species (text-fig. 76 c); the third outer segment has on the left

side, as seen in text-fig. 76 d, a somewhat different shape from that of O. hirtipcs.

COPEPODA

^35

Occurrence. The Thor has gathered 2 specimens:

"/; 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire i f?.
1% 1904 St. 180 6i°34 L. N. i6°05 L. W. Yt. 1800 M. Wire i fj-.

Remarks. It is not without some doubt that I have established a new species for the described
male and female. In spite of the variations in the fifth pair of legs, which is not uncommon to
several species, I think that the different shape of the fifth pair of legs, the larger size, and the dif-
ferent armament of the first pair of legs warrant the establishment of a new species for the female.
I think that the males of the two species are distinctly distinguishable especially by the right leg of
the fifth pair of legs.

76. Xanthocalanus Greenii Farran.
(PI. VII figs 3 a— g; PI. VIII figs 18 a— d).

1905. Xanthocalanus Greenii n. sp. Farran, p. 39, pi. VIII figs

I-I3-

1906. — — Farr. Pearson, 20.

1906? — calaminus n. sp. Wolfeuden, p. 34, pi. XI

fiss 3-5-

1907. — Greeni Farr. G. O. Sars, p. 13.

1908. Xanthocalanus Greeni Farr F'arrau, p. 48.
1908. — — — V. Bremen, p. 60, fig. 67.

1908. — calaminus Wolf Wolfenden, p. 34.

1911? Talacalanus calaminus Wolf. Wolfenden, pp. 279 — 281,
Taf. XXXI, figs 9 — 12, text-figs 44 a— b.

Description. YJ* (St. V). Size of young male was 8-i2 mm.; anterior division 6-69 mm.; uro-
some 1-43 ram. Farran's specimen measured 6-o mm. and Wolfenden's 5-5 mm.

The anterior division is short and robust, about 4-5 as long as the abdomen. The rostrum
consists of a proximal portion, continued into 2 thin, but stiff, rather long and somewhat divergent
branches (PI. VIII fig. 18 a). The head is rounded without any trace of crest. The first thoracic tergite
is well marked in front by an articular line, which, beneath, is seen to be continued between the in-
sertion of the maxillae and maxillipeds, as is the fifth thoracic tergite, as seen in fig. 18 b. The lateral
corners are produced and terminated with a small tooth.

The comparative length of the abdominal somites and the furcal branches is 10, 17, 13, 7 and
15; the furcal branches are 1-4 as long as wide; serrated seam along the hinder margin of somite
II — III is well developed.

The antennulae extend almost to the end of body; the appendages of the 24 segments are
like those of the preceding species; the Sp. of segment 24, which was broken, was placed in the
middle of the segment; the measurements are in the main like Farran's description. The antennae
are like Farran's description, with two rami of about equal length. The iiiandibtilae \\a.\Q a long and
slender manducatory part with rather weak teeth; the third basipodite has three long slender spines,
of which the most distal is almost twice as long as the proximal ones. The maxillulae have 7 long
powerful + shorter bristles in the exterior lobe; the Li I (PI. VII fig. 3 a) has 4 rather delicate Sa and
10 Sp., of which at least 8 are widened out to lancet-shaped laminae with delicate serration, as seen
in fig. 3 b; the Li 2 has 4 setae, and so has Li 3, and while the third basipodite has 4 Sa + i Sp the
endopodite has 11 setae and the exopodite 10. The maxillae are only slightly produced posteriorly;
Lob. I has 5 setae, lobe II— III has 3 setae, and lobe IV (PI. VII fig. 3 c) has a strong sHghtly curved

30"

236

COPEPODA

serrated spine in addition to the usual pinnate setae with laminae-formed serrated membrane; the lobe
V has two rather delicate bristles posteriorly, of which one is short, and in addition 2 very long ser-
rated membraniferous setae (figs 3c-d). The endopodite (cf. Wolfenden's PL XXXI fig. 11) has 7
longer or shorter brush-shaped sensory setae as well as a long slender vermiform one. The viaxillipeds
(PI. VII fig. 3 e) are in main features like those described b)' Farran and Wolfenden; the compara-
tive length of the main divisions is 47, 41 and 43; the first basipodite has in the middle no brush-
shaped seta, but a fairly long pointed seta; the second basipodite is distinctly twice as long as wide.
The two last setae of the segments of the endopodite are curiously developed, as shown in fig. 3 f
(PI. VII); the last segment has in addition to these two setae two simple setae and a plumons one
(not drawn by Wolfenden).

"YXx^ first pair of legs is like Sars' figure of X. borealis, but the Se of Re I and II are short,
as seen in Farran's fig. 9; both surfaces are smooth. The second pair of legs has a short blunt Se
in the first inner segment (fig. 18 c); the second inner segments possess on the posterior surface two
groups of 12 strong spines; the posterior surface of the exopodite is completely smooth; the terminal
seta is short and broad (PI. VII fig. 3 g), and its teeth are only free in their terminal portion; well
developed glandular pores are found in Re I, II and III at the base of Se 3. The third pair of legs is
like that of the preceding pair, but the second inner segment has 9, and the third inner segment has
7 spines. Tlie fourth pair of legs has on the posterior surface of the second inner segment 19 com-
paratively short and slender spines; on the posterior surface of the third inner segment a number of
short bristles is found.

The fifth pair of legs of the examined specimen, which is probably a young male, is distinctly
different from Farran's description of a young male, and is asymmetrical; the left smaller leg consists
as seen in fig. 18 d, of three segments; the exopodite has two outer and a terminal spine; a rudimentary
styliform endopodite is present. The right leg is somewhat longer than that of the left side, and the
endopodite as well as the exopodite has two segments.

The lateral outhne of the labrum etc. is, as seen in fig. 18 a (PI. VIII), rather characteristic.

Occurrence. The Thor has in 1904 or 1905 in the Atlantic south of Iceland without locality
taken a young male of this interesting species.

This species has previously been recorded from the west coast of Ireland "at depths of from
680 to 1 150 fathoms", from the Bay of Biscay and by the Monaco Expedition.

Remarks. On full consideration I think that this species is identical with Farran's X. Grcnii
in spite of the larger size and the distinct tooth of the lateral corner. It is probably also identical with
Wolfenden's X. calaviimis^ though differing in the features mentioned as well as in a few others.

77. Xanthocalanus pinguis Farran.
(PI. VII figs 2 a— d, text-figs 77 a— b).

1S97? Xanthocalanus hirtipes n. sp. Vanhoffen, p. 282, fig. iS.
1905- — pinguis u. sp. Farran, pp. 39— 40, pi VIII

—IX.
1906. — — Farr. Pearson, p. 20.

1908. Xanthocalanus pinguis Farr. Farran, p. 4S, pi. IV fig. iS.
1908. — — — V. Bremen, pp.60— 61, fig.68.

1908? — — — Wolfenden, p. 35.

COPEPODA ' 237

Description. f$. Size of female from Thor St. 99 was 5-19 mm.; anterior division 4-15 mm.;
urosome 1-04. Farran's specimens measured 4-5— 5-1 mm.

The shape of the body is in the main like that of A', borealis. The first and fifth somites, bnt
especiall)- the fifth, are well marked in front (text-fig. 77 a); the lateral corners are produced into a small tooth

The abdomen^ which is one fourth as long as the anterior division, has a slightly produced
genital somite, and a distinct receptaculum seminis; along the hinder margin of somites II — IV a striated
seam is found ; the comparative length of the first three abdominal somites and the furcal rami is 18,
12, 9 and 8.

The antennulae extend to the end of the fourth thoracic tergite, and consist of 23 segments;
the number of "^sthetasken" is like that of C. chelifer\ a proximal seta was found in segments 12, 14,
16 and 18, but not in segments 15 and 17; the posterior seta of segment 24 is placed in the middle
of the segment, and extends just to the end of segment 25. Segment 24 is i'2 as
long as 23, and i'5 as long as 24, which is as long as segment 22.

The exopodite of the antennae is distinctly longer than the endopodite.
The mandibulae are scarcely different from those of X. borealis^ while the maxillulae^
especially the distal portions, are more long and slender than in X. Grceni as well
as borealis\ the number, but not the shape, of setae in the inaxilholae is as in X.
Greeni] but the endopodite has only 9 setae. The maxillae are \\kft Sars' and Far-
ran's figures; the lobe V has in addition to 3 setae, of which the two are .short
and delicate, a serrated and distinctly curved spine, which is longer and stronger
than that of the fourth lobe; the endopodite has 7 brush-shaped sensory setae in Text-fig. 77. Aa«^Ao-

j , . calanus pinguis Farr.

addition to a vermiform one. The maxilhpeds are somewhat less slender than ni a. f 9. Genital somite

X. borealis: the sensory seta of the second basipodite is fairly long and brush-shaped; X 18. b. yd (St. V).

' ^ . . Abdomen X 18.

the comparative length between the main divisions is 65, 73 and 48.

The//>j/ pair of legs is like that of X. borealis, but the Se of Re I extends almost to the end
of Re II. The second pair of legs differs from that of X. borealis by finer serration of St; the glan-
dular pores are like those of the preceding species. The Si of the second basipodite shows an abnormal
structure probably due to traumatism, as it is suddenly narrower and then gradually enlarged,
where it is divided into three again subdivided branches. The third zyxA fourth pair of legs, the distal
segments of which were wanting, are scarcely different from those of A', borealis. The fifth pair of
legs (PI. VII fig. 2 a) is in main features like Farran's earlier description, and is scarcely different from
the fignre which Far ran has given of a larger specimen (his PI. IV fig. 18); the anterior surface is
smooth, but the posterior surface has, as shown in figure, groups of short spines.

The lateral outline of the epistoma and labrum is like that of A'. Greeni, as seen in figure,
and they are not distinctly defined from each other. The epistoma has in front a group of long slender
bristles; somewhat in front of the transverse row of bristles along the posterior margin a regular
transverse series of fairly long setae is found, and just in front of this a group of irregularly placed
bristles is found ; laterally two or three groups of short hairs are found.

On the oral surface of the labnuu (PI. VII fig. 2 b), in front and laterally, two oblique almost
parallel wide rows of bristles were observed; in the middle, on each .side, 4 more or less fu.sed wide

238

COPEPODA

areas of numerous short hairs or granules were observed. The chitinous framework is on each side
in front of the third median circular spot produced into a beak-like structure; somewhat behind, a
transverse chitinous bar was found in the middle. Behind the fourth median circular spot a number
of short granules was found.

In front of the indistinct lamina labialis a large group of short hairs is observed, consisting of
an inner and outer part; the hairs decrease in size outwards. Between the srrrula 6-scrrata a
crroup of granules is observed, and behind, outer and inner groups of longer and shorter hairs, as seen
in figure 2 c (PI. VII). Along the labial lobes inwards, marginal rows of long slender setae are found
anteriorly and short spines posteriorly; behind the lobes in the middle, areas of minute granules are
found, and the lobes possess laterally groups of irregularly placed fairly long and .slender bristles,
limited inwards by an oblique row of somewhat shorter hairs.

Yq (St. V). Size of young male was 4-43 mm.; anterior division 3-51 mm.; urosome 0-92. An-
other young male as well as a female measured 37 mm.

The shape of the body differs from that of the adult by the comparatively better marked fifth
thoracic somite (text-fig. 77 b), and by the abdomen, which has four somites, the comparative length
of which is 5, 13, 9, 6 and 5; the furcal rami are a little longer than wide. The Ji/fh pair of legs in
the female is scarcely different from that of the adult; in the male (PI. VII fig. 2 d) it is distinctly
different; on the right side it differs by the two-segmented exopodite, the first segment of which has
a distinct Se, and the terminal segment of which has 2 terminal spines; the left leg shows a similar
segmentation, but is less hirsute and shows trace of segmentation in Re II.

Occurrence. The Thor has gathered this species once in the Iceland-Faeroe channel and
once in the Atlantic south of Iceland.

"/5 04 St. 99 6i°05 L. N. 9°35 L. W. Yt. 1700 M. Wire 2 f?, 2 y? (V), 3 yd' (V).
■^/, 04 St 78 6i°o8 L. N. 28° L. W. I yd* (V).

Distribution. This species has been recorded from the west coast of Ireland "at a depth of
630 fathoms". If it is identical with X. Iiirtipes Vanh. and borealis G. O. Sars, it has a wide distribution
viz. the west coast of Ireland, the Iceland-Faeroe channel, the west coast of Norway, Kara Sea and the
Arctic Ocean near the New Siberia Islands.

Remarks. That this .species is identical with the species which Parr an 1908 has mentioned
as X.piiigiiisf seems not to be doubtful on account of its size 5-1 mm. and the almost identical shape
of the fifth pair of legs. From the typical specimens of Farran's species (1905) it differs by the more
pointed lateral corners of the fifth thoracic tergite, and by a somewhat different measurement of the
antennulae [the segment 22 is as long as instead of 1-3 (in fig. 20 PI. \'III the two segments are of
almost equal length) as long as segment 25], but especially by the more distinct spinulation of the
fifth pair of legs. When the variability of the fifth pair of legs is taken into consideration, I do not
doubt that the two different forms belong to the same species.

It is nearly related to X. profundus Sars (1907 p. 14), which differs from it by larger size,
6-2 mm., and by the somewhat different shape of the fifth pair of legs.

COPEPODA

239

From X. liirtipcs and borcalis, to which it is very nearly related, it seems to differ by greater
size, by comparatively shorter antennulae, which do not reach to the end of the genital somite, and
by 10 instead of 9 setae in the exopodite of the antennae.

78. Xanthocalanus claviger Th. Scott.

(Text-figs 78 a— d).

1909. .\iiiallophora claviger n. sp. Th. Scott, pp. 124—125, pi. Ill figs i - 11, pi. IV figs 13 — 17.

Description, fc?. Size of male from Tlior St. 183 was 4-55 mm.; anterior division 3-22; uro-
some 1-33 mm.

The shape of the body is like that of A'. horealis\ the head has no crest; the rostrnm is
broken but seems to be fairly long, and is directed somewhat backwards. The lateral corners of

wi
o

Text-fig. 78. Xanthocalanus claviger Th. Scott, id-

a. Abdomen X 23- b. Pes V sin. Re II— III in situ from the left side X 122. c. Pes V sin. Re II— III in

ant. view X 240. d. Pes V dext. in exterior view X 122.

the thorax are regularly rounded. The head and the fourth somites are almost completely fused
th the following ones. The anterior division is 24 as long as the urosome; the comparative length
f the abdominal somites are seen in the fig. 78 a. The serrated seam along the hinder margins is
poorh' developed.

The antennulae extend distinctly beyond the end of the thorax to the end of the second ab-
dominal somite. Segments %^<^ are only in front indistinctly separated from segments 10—12, which
are completely fused; these segments are fairly well separated from segment 13, which is well
separated from segment 14; the following segments are well separated from each other. A complete
"trithek" is found in segments 3— 9; ".^sthetasken" are found in segments 10—19, but are wanting in
segments 20—24. Small proximal setae are seen in segments 12, 14, 16 and 18.

The exopodite of the antennae is 1-5 as long as the endopodite, which has 6 setae in the
outer and 8 in the inner lobe of the second segment. The manducatory part of the mandibulae is
soft-skinned and very long and slender, with delicate but distinct teeth; the third basipodite is widened

2AO COPEPODA

out and possesses 2 long Si. The )iiaxiUulac are fairly well developed, and different from those of the
male of X. borealts; the Le has 7 long powerful as well as 2 short bristles. The Li i is only a little
longer than wide, and has at least 9 bristles, which are long, broad, somewhat lamellous and distinctly
plumous; the Li 2 has 4 short setae, the Li 3 has 4 fairly long, partly phunous setae, and the third
basipodite has 5 setae. The endopodite seem.s only to possess 10 setae, and so does the exopodite.
The maxillae are rather soft-skinned; the Lob. I has 4 rather slender setae, the lob. 2-3 have 3 each;
the fourth lobe has 2 slender plumous bristles and a long, broad, strongh- plumous seta, and the fifth
lobe has a single shorter one of similar structure in addition to 2 fairly strong plumous setae and a very
delicate one. The endopodite has 2 vermiform setae, 5 rather slender brush-shaped ones, and a curious
globular appendage scarcely twice as long as wide, with terminal almost circular opening and striated
wall. The viaxilUpeds are scarcely different from those of X. borcalis.

The first and second pairs of legs are scarcely different from those of X. borcalis ] the distal seg-
ments of the fhird anA /otirfJi legs are wanting, while the proximal ones are like those of mentioned
species. The fi/f/i pair of legs extends distincth- beyond the end of the abdomen; the rig/if leg is
comparatively short and somewhat convex outwards, but extends distinctl\- beyond the end of the
first basal segment (text-fig. 77 a, d); it consists, as seen in figure, of 4 segments, of which the last one
shows trace of further segmentation, and is terminated with a short tooth. The Ic/f leg consists of
three elongated proximal segments, the comparative length of which is seen in figure; the first seg-
ment has inwards on the anterior surface a short keel (text-fig. 77 a — c). The fourth segment (Re II?)
is much shorter than the preceding ones, and is somewhat enlarged towards the middle, where a
process with two groups of about 10 bristles is found; beyond this process the segment is hollowed
with a concavity facing inwards, and has about 6 setae along the outer margin, as well as a tuft of
5 more slender ones and one stronger seta terminally (text-fig. 78 b — c); apparently articulated to this
segment a short "segment" with a tuft of hairs was found. The terminal segment (Re III?) has along
the one margin in the middle 5 fairly strong spines, and terminalK- a hooked spine; at base of which
four moderately slender setae are observed.

Occurrence. The Thor has collected a single male.

11/7 1904 St. 183 6i°30 L. N. i7°o8 L. W. Yt. 1800 M. Wire i i^.

Distribution. A few males have once been taken '7/3 1908 59°36 L. N. 7° L. W. Depth 1140 Meters.

Remarks. As far as I am able to see the male of this species, which is especially characterized
by the curious development of the left foot, is identical with Scott's Amalloplwra claviger. The
somewhat laminous setae which are observed in tlie maxillulae and maxillae suggest some affinity to
X. Grenii\ its much smaller size excludes this species.

About 20 species of Xanthocalatius have been described; to refer the described male to most
of these may be excluded, especially on account of its much greater size (4-5 mm. against 2 — 3 mm. for
the female). Only X. pinguis Farr. (4-5 — 5-1 mm.), X. initticiis G. O. Sars (53 mm.) and X. profundus
G. O. Sars (6-2 mm.) could possibly be the females of this species. From X. piiiguis it seems to be
distinguished by rounded lateral corners and longer antennulae. From X. proftdidus it seems to differ
in quite similar features, and from X. mtiticus it seems to differ by longer rostrum, by lateral corners

COPEPODA

241

rounded not "obtusement triangulaire", by longer urosonie, by shorter antennulae not "aussi longues
que le corps". I think it is quite impossible at present to tell whether the described male ought to
be regarded as identical with any of these three species, or whether it is the male of a not yet
described female.

1897.
1900.

1902.

1902.
1903-

1904. ? 9 nee cf

1905-

Xantliocalauus hirtipes n. sp. Vanhoffeu, p. 2S2, fig. 18.

— borealis n. sp. G. O. Sars, pp.49 — 51,

pi. XI.

— — G. O. Sars. Th. Scott, pp. 452

—453, pi. XXII figs S-9.

— hirtipes Vanh. Mrazek, p. 523.

— borealis G. O Sars. G. O. Sars, p. 46,

pi. XXXI-XXXII.
subagilis 11. sp. Wolfenden, p. 118, pi.

IX figs 17—32.
borealis G. O. Sars. G. O. Sars, p. 5.

79. Xanthocalanus hirtipes Vanhoffen.
1905-

1906.
1907.

1908.

1908?
1913-

Xanthocalanus borealis G. O. Sars. Farran, pp. 38—39,

pi. VIII figs 14—17.

— — — Pearson, p. 20.

— — Vanh. Vanhoffen, pp. 514 —
517, Taf. 21, fig. 16—22.

— — G. O. Sars. v. Bremen, pp. 58 —

59, fig. 66.
pars. — subagilis Wolf. v. Bremen, pp. 62—63,

fig. 71.

— borealis G. O. Sars. Wolfenden, p. 33.

— hirtipes Vanh. Stephensen, p. 318.

Of this sjDecies I have only examined a single, very mutilated, adult female found in the con-
tents of the stomach of a Liparis barbata from Kara Sea. I have included it in this paper partly
because it certainly belongs to the fauna of this region, and partly because a full synonymy and a
discussion of its position seem to be useful.

The lateral corners of the thorax are distinctly pointed, as in Sars' figure PI. XXXI. The exo-
podite of the maxillulae has only 9 setae, as stated by Sars.

The fifth pair of legs is most similar to that described by Vanhoffen (Taf. 21 fig. 22), with
three terminal spines only, but the last segment is fairly well distinguished, and the hairs, especially
those of the posterior surface of the third segment as well as those of the inner surface of the first
segment, are distinctly longer. The labrum etc. are in all main features like that of the preceding species.

To decide whether X. hirtipes and borealis really belong to the same species is somewhat dif-
ficult without specimens of both forms at disposal. The character found in the size is not of much value,
when remembering that Farran's specimens varied from 2-5 to 3-5, that Sars' measured 3-5, and
Vanhoffen's 4 mm.; the characters found in the structure of the fifth pair of legs are not sufficient,
when taking into consideration the great variations which, according to Farran, exist in the structure
of this pair of legs. Vanhoffen thought that characters could be found in the spinulation of the
posterior surface of the endopodites of the natatory legs; the differences pointed out by him are cer-
tainly due to individual variability. To define the limitations of the species within this group is
probably a task just as difficult as that which has previously been discussed with Oilainis and Psni-
docalamis.

80. Phaenna spinifera Claus.
(PI. VII figs I a— c; text-fig. 79).

1863. Phaenna spinifera n. sp. Claus. p. 1S9, Taf.XXXI figs i — 7.

1892. — — Claus. Giesbrecht, p. 293, Taf. 5, 12, 37.

1893. — — — Th, Scott, p. 81, pi. VI— VII.
1898. _ _ _ Giesbrecht & Schmeil, p. 50.
1903. — — — J. C. Thompson, p. 23.

Tlie Inoolf-Exjieditioii. HI. 4.

1903. Phaenna spinifera Qaus. Thompson & Scott, p. 246.

1903. — — — Cleve, p. 367.

1904. — — — Wolfenden, p. in.

1904. — — — Cleve, p. 194.

1905. — — — Wolfenden, p. 1009.

31

242

COPEPODA

1905. Phaenna spinifera Claus. G. O. Sars, p. 5.

1905. — — — Farran, p. 47.

1906. — — — Pearson, p. 21.
1908. — — — Farran, p. 47.

1998. — — — V. Bremen, p. 56 fig. 63.

1909. Phaenna spinifera Claus. Pesta, p. 22.
1909. — — — A. Scott, p. 80.

191 1. — — — Wolfenden, pp. 285— 2S6.

1912. — — — Pesta, p. 24.

Description. f$. Size of specimen from Thor St. 82 was a'gmm.; anterior division 2'42; nro-
some 0-48 mm. Giesbrecht's specimens measured i'8 — 2-i mm.

In some of the examined specimens the liead possesses dorsally, as seen in text-fig. 79, a conical
protuberance.

The interior lobes of the viaxillar are placed verj' near to each other, the Lob. i has 5 setae,
the lyob. 2 has 3, and the Lob. 3, whicli is very short, has probably 3 setae as well; the fourth lobe
has at least 2 setae, of which the one is comparatively strong, and distinctly curved, and the fifth
lobe has in addition to fairly strong claw-shaped setae two short slender ones; the endopodite has seven
comparatively short and thick brush-shaped setae, distally apparently fused, in addition to a long and
slender pointed one.

The legs are scarcely different from Giesbrecht's description. The outer margin of the third
outer segment of \.\\& first fo of has proximally to the middle a small incision and a glandular pore. On
the anterior surface of the third inner segment of the second and third pairs of legs a
minute glandular pore was found, but in the fourth pair none was seen. At the base
of the outer spine in the Re II, and at the base of Se I and III Re III, glandular
pores were found in the second pair of legs, and in the third and fourth pairs at the
base of Se Re I as well. The Ri II '>^ III, which are fused in the second pair of legs,
possess on the posterior surface two coronas of 8 and 6 long spines respectively, the
Ri II and III of the third pair of legs have 8 and 6 spines respectively, and the Ri II
of the fourth pair of legs has 6 long rather weak spines.

The very short lahniiii and the elevation in front of it are only indistinctly
separated, and the latter is placed just behind the insertion of the antennulae; the epi-
stoma is covered by a number of longer and shorter setae; on the labrum proper a trans-
verse group of fairly short setae is found ; the marginal setae are only poorly developed (PI. VII fig. i a).
The oral surface (fig. i b) has in front 4 longer and shorter oblique groups of shorter hairs converging
towards the middle, and more posteriorly, probably composed of the three hinder, a longitudinally placed
elongated groujj of short hairs is found. In the middle at least three groups of very short hairs or
granules are found. The lamina labialis is only poorly developed (PI. VII fig. 1 c); in front of it a
regular granular area is found; the area behind the lamina and on the labial lobes was not studied
in details (of. fig. i c).

f c?. Size of specimen from St. 82 was 2"26 mm.; anterior division I'Sg mm.; urosome 037 nmi.
Giesbrecht's sj^ecimen measured 18 mm.

The anterior division did not possess a lamelliform projection, as figured and described by Gies-
brecht. No dorsal protuberance was found.

Y$ (St. V). Size of specimen from Thor St. 82 was 2-3 mm.

The only difference was found in the different structure of the abdomen.

Text-fig. 79.
Phaenna spini-
fera Claus.
f9- Lateral out
line of body
X 18.

I

COPEPODA 243

Occurrence. The S S Thor has gathered a few specimens of this interesting form, viz.:

H/g 1905 St. 82 5i°oo L. N. ii°43 L. W. Yt. 800 M. Wire 8 f?, i f^?, 2 y? (V).

Yt. 1200 M. Wire i f?.

2% 1905 St. 88 48=09 L. N. 8°30 L. W. Yt. 300 M. Wire 3 f?.

This species has been recorded from the west coast of Ireland, from the mid and south Atlantic,
from the Mediterranean, the Red Sea, the Indian Ocean, the Malay Archipelago and the Pacific Ocean.

Remarks. In spite of the greater size I regard this species as identical with that described
by Giesbrecht.

I am much indebted to Mr. Norman H. Beale, who has kindly undertaken the revision of
the language of this paper, as well as to Messrs. Hendriksen, who have taken great trouble in the
reproduction of the text-figures.

31'

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Dansk. Vid. Selsk. Nat Math. Afd. 1838.

— : "Crustaces' '. In: Voyages de la commission scientifique du Nord en Scandinavie etc. P. Gaimard. Paris. Atlas, taf. 41

—43. 1S42-1845.

— : "Karcinologiske Bidrag". Naturh Tidsskrift Ilden Raekkes Ildet Bind, pp. 527 — 560, pp. 563 — 609, tab. VI. 1846—49.
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* T • 1

Ivinko, A. K. : "Zooplankton de la mer glaciale de Siberie etc." Mem. Ac. Sc. St. Petersburg Ser. VIII 20 livr. Nr. 4, pp.

1—54. 2 pi. 1913.
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part 2. London, pp. 8 — 39, pi. 2 — 12. 1856.
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pp. 269—276, Taf. VII— VIII. 1895.
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PP- 133-141-
Norman & Th. Scott: "The Crustacea of Devon and Cornwall". London 1906. 232 pag, 14 plates.
Oberg, M.: "Die Metamorphose der Plankton-Copepoden der Kieler Bucht". Wiss. Meeresunt Abt Kiel. N. F. Bd. IX, pp.37

— 102. 1905.

COPEPODA 247

Paulsen, Ove: "Studies on the Biology of Calanus finmarchicus in the waters rouud Iceland'. Medd. f. Komni. f. Havunders.
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— : "Plankton Investigations in the waters round Iceland and in the North Atlantic in 1904". Medd. Komui. Havunders.

Vol. I, pp. I — 57. 1909.
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telmeeres". Denkschriften Akad. der Wisseuschaften. Bd. LIV. Wien 1909, pp. 19—31 figs 1—5. 1909.

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Hchen Mittelmeeres". Denksch. Akad. der Wissensch. Bd. LXVI. Wien, pp. 11 -28, taf. I— II. 1912.
Poppe, S. A.: "Ueber die von den Herren Dr. Arthur und Aurel Krause im nordlichen Stillen Ocean und Behringsmeer ge-

sammelten freilebenden Copepoden". Arch. Naturg. 50. Jahrg., p. 281—304, Taf. 20 — 24. 1884.
Sars, CO.: "Crustacea 1". The Norwegian North-Atlantic Exped. 1876 — 1878. Zoology, pag. 280, plates 21. 1885.
"Crustacea II". loc. cit., pag. 163, pi. 15. 1886.

"Crustacea". "The Norwegian North Polar Exp. 1893 — 1896". Scientific Results V, pp. 1-141, pi. I— XXXVI. 1900.
"An account of the Crustacea of Norway". Vol. IV Copepoda. Calanoida, pp. i— 71, pi. I— CH, Supp. pi. I— VI. 1902 — 1903.
"Liste preHminaire des Calanoides recueillis pendant etc. (I)". Bull. Musee Oceanograph. de Monaco Nr. 26, pp. 1 — 22. 1905.
"Liste preliminaire des Calanoides etc. (II)'. Bull. Musee Oceanograph. Monaco. Nr. 40, pp. 1 — 27. 1905.
"Notes supplementaires sur les Calanoides de la Princesse-AIice". Bull, de I'lnstitut Oceanographique Nr. loi, pp.
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Scott, A.: "The Copepoda of the Siboga Expedition, part i". Siboga Expeditie. Monog. 29a, pp. 1—323, pi. I— LXIX. 1909.
Scott, Th.: "Report on the Entoniostraca from the Gulf of Guinea collected by John Rattray". Trans. Linn. Soc. London.
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Museum. Vol. 12, pp. 313 — 3S2, pi. XV - XXIV. 1912.
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Vol. XXXVIII, pp. 405— 436, figs 1—20. 1910.
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pi. 10—13. 1888.

248

COPEPODA

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pi. I -VII. 1903.
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pp. 183—380, Taf. XXll-XLI, text-figs 1—82. 191 1.

i

i

I

I

EXPLANATION OF THE PLATES.

Plate I.

Fig. I. Calanus hyperboreus Kroyer.
Fig. I a. f $. Marginal setae of the labrum ; x 77.

— lb. f 5. Oral surface of the labrum ; x 200.

— I c. f^. Lamina labialis etc. 1 = lamina labialis, s = .serrula 6-dentata; x 200.

— id. f$. Lobi labiales and area behind, a — c = articular cavities of the maxillulae, maxillae and

maxillipeds; x 44.

Fig. 2. Macrocalanus princeps Brady.
Fig. 2 a. f $. Oral surface of the labrum; x 57.

— 2 b. f$. Lamina labialis and anterior surface of the lobus labialis; x 57.

Fig. 3. Megacalanus princeps Wolfenden.
Fig. 3 a. f^*. Labrum, lobi labiales and area behind from below; x 24.

— 3 b. f $. Oral surface of the labrum ; x 77.

— 3 c. f ?. The lamina labialis, the lobi labiales and the right mandibula in ventral and partly anterior

view, s = serrula 6-dentata; 1 ^ lamina labialis; x 57.

— 3d. f$. The left maxilla; x 24.

— 3 e. f$. The left second foot in anterior view, gl = glandular pores; x 24.

— 3 f. f ?. Se Re I pes II sin. in anterior view; 1 = lamina cribrosa; gl = glandular pore; > 44.

— 3 g. f?. The lamina cribrosa; x 280.

— 3 h. f $. The left fifth foot in anterior view; x 24.

— 31 f c?. The segment 6 (VI) to segment 11 (XI) of left antennula; x 24.

Fig. 4. Rhincalanus nasutus Giesbrecht.
Fig. 4 a. Y$ (V). The anterior part of the body in left view; x 24.

— 4 b. f $. The right side of the abdomen in abnormal specimen ; x 44.

— 4 c. f $. The lamina labialis etc. ; x 200.

— 4d. f?. The fifth foot in abnormal specimen from Thor 1905 vSt. 88; x 90.

— 4 e. f c?. The oral surface of the labrum; x 280.

— 4 f. f c?. The left antenna in posterior view; x 38.

— 4g. f c?. The fifth foot in posterior view of specimen from Thor 1905 St. 88; x 90.

— 4h. f c?. The fifth foot in posterior view of specimen (Nr. 2) from Thor 1905 St. 88; x 90.

— 4i. f c?. The fifth foot in posterior view of specimen (Nr. 3); x 90.

— 4 j. f c?. The fifth foot of an abnormal specimen from Thor St. 88; x 90.

— 4k. Y<^ (V). The fifth foot in posterior view; x 90.

— 4I. Yc? (IV). The fifth pair of legs in posterior view of specimen from Thor 1905 St. 72; x 90.

The Ingolf-Expedition. III. 4. -

2 CO COPEPODA

Fig. 5. Eucalanus elongatus Dana.

Fig. 5 a. f $. The oral surface of the labrum; x 200.

— 5 b. f ?. The lamina labialis etc. ; x 200. ^

— 5 c. f c?. The fifth pair of legs in anterior view ; x 65.

— 5d. Yc? (V). The fifth pair of legs of an abnormal male; x 65.

— 5e. Yc? (V). The fifth foot in ant. view; x 65.

— 5f. Yc? (V). The fifth foot in ant. view; x 65.

Fig. 6. Eucalanus attenuatus Dana.
Fig. 6a. Y? (V). The oral surface of the labrum; x 200.

— 6b. Y? (V). Lamina labialis; x 200.

— 6c. Yc? (V). The fifth foot in post, view; x 77.

Fig. 7. Eucalanus crassus Giesbrecht
Fig. 7 a. f $. The coecal sac; x 44.

Fig. 8. Pseudocalanus minutus Kroyer.
Fig. 8 a. f $. The oral surface of the labrum ; x 280.

Fig. 9. Clausocalanus arcuiformis Dana.
Fig. 9 a. f 5. The head etc. from the left; x 77.

— 9 b. f ?. The genital somite from the left; x 77.

— 9 c. f $. The oral surface of the labrum ; x 260.

— 9 d. f $. The lamina labialis etc. ; x 260.

Fig. 10. Spinocalanus abyssalis Giesbrecht
Fig. 10 a. f 5- The oral surface of the labrum ; x 260.

— 10 b. f $. The lamina labialis etc. ; x 260.

Plate II.

Fig. I. Aetidius armatus Boeck.
Fig. I a. f$. F'irst abdominal somite from the left; x 152.

— lb. f?. First abdominal somite from below; x 152.

— I c. f$. Basipodite of pes IV sin. in posterior view; x 152.

— id. f$. Lamina labialis etc.; x 280.

Fig. 2. Chiridius obtusifrons G. O. Sars.
Fig. 2 a. f$. The labial structures; x 280.

— 2 b. Yc?(V). Pes V; x 77.

Fig. 3. Chiridius armatus Boeck.
Fig. 3 a. f$. Pes II sin. anterior view; x 77.

— 3 b. f$. Labrum -oral view, g^— g^ the second and fourth groups of the lateral longitudinal series.

St the fourth central circular spot; x 200.

— 3 c. f$. Lamina labialis and serrulae 6-dentatae; x 280.

— 3d. f$. Area labialis et postlabialis; x 147.

— 3e. fc?. Pes V sin; the endopodite; x 280.

A

COPfiPODA

251

Fig. 3 f . fc?. Pes V sin; the last segment of the exopodite; x 280.

— 3 g. fc?. Pes V dext; the exopodite; x 47.

— 3h. Yc? (V). Pes V; x 77.

— 3i. Yd* (IV). Pes V; x 117.

— 3J. f?. Pes V in anterior view from abnormal specimen (Thor *'/g 05 St. 172); x 77.

— 3 k. f?. Pes V in anterior view from abnormal specimen (Thor 7/9 05 St. 173); x 77.

— 3 1. f$. Pes V in anterior view from abnormal specimen (Thor 2^/5 04 St. 72); x 77.

Fig. 4. Chiridius nasutus n. sp.
Fig. 5. Chiridius modestus n. sp.

Fig. 4a. f$. Pes II sin; x 77.

Fig. 5 a. f$. Pes II sin; x 77.

Fig. 6. Aetidiopsis rostrata G. O. Sars.
Fig. 6 a. f?. Anterior portion of oral surface of labrum; x 280.

— 6 b. f?. Lamina labialis etc. partly in anterior view; x 280.

Fig. 7. Gaidius brevispinus G. O. Sars.

Fig. 7 a. f$. Rostrum, observed from below; x 200.

— 7b. f$. Abdomen with .spermatophore in lateral view; x 44.

— 7 c. f$. Genital area; x 117.

— 7 d. f$. Exterior margin of maxilla sin. in post, view; x 77.

— 7 e. f?. Inner margin of basp. of left pes IV in posterior view; x 117.

— 7 f. f$. Labrum et labium; x 200. g^ and g-t the second and fourth group of the lateral longi-

tudinal series; S'— S? the seven lateral series of hairs upon, between and behind the
labial lobes.

— 7 g. fc?. Inner margin of basp. of left pes IV in post, view; x 117.

— 7 h. y c?. Pes V ant. view ; x 77.

Fig. 8. Gaidius tenuispinus G. O. Sars.
Fig. 8 a. y<^. Pes V ant. view; x 77.

Plate m.

Fig. I. Gaidius brevispinus G. O. Sars.
Fig. I a. f?. Maxillipes sin. in post, view; x 77.

— lb. f$. Maxillipes sin.; basipodite III; x 77.

— I c. f?. Pes IV sin. The basipodite in posterior view; x 152.

— id. f c?. Manducatory portion of the mandibula; x 152.

— I e. fc?. The left maxillula in posterior view; x 117.

— if. fc?. Maxillipes sin. in posterior view; x 77.

— I g. fc?. Pes I sin. in nearly anterior view; x 117.

— I h. f^. Pes V in posterior view; x 77.

— I i. fd*. The terminal segment of the left pes V; x 200.

— I j. f c?. The terminal segment of the right pes V; x 200.

Fig. 2. Gaidius tenuispinus G. O. Sars.
Fig. 2 a. f^. The rostrum in dorsal view; x 200.

— 2 b. f$. The ba.sal segments of the left antenna; x 77.

32*

2r2 COPEPODA

Fig. 2c. f?. Maxillipes siu. Lobus IV of basipod. II in anterior view; x 152.

— 2d. f?. Pes I. The terminal seta of the last segment of the exopodite; x 117.

— 2 e. f?. The oral surface of the labrum; x 280.

— 2 f . fd*. Rostral spine; x 77.

— 2 g. fcf. Rostrum seen from below; x 200.

— 2 h. f c?. Maxilla ; x 280.

— 2 i. fc?. Pes I. The terminal seta of the last segment of the exopodite; x 117.

— 2J. fc?. Re II of left pes V in exterior view sitting on the animal; x 200.

— 2 k. fj". Tip of Re III of left pes V; x 280.
2 1. fc?. Ri of right pes V in situation, seen from the left side; x 200.

— 2 m. fc?. Re I<N)II of left pes V; x 77.

— 2n. f(?. Pes V dext. The third segment of exopodite from inner side; x 280.

Fig. 3. Gaetanus major Wolfenden.

Fig. 3 a. f?. Setae of inner margin of basipodite II of pes IV in posterior view; x 117.

— 3 b. f$. Portion of the labrum (oral view); x 280.

— 3c. f$. Lamina labialis etc. observed partly from in front; x 200.

— 3d. fc?. Pes V in posterior view; x 37.

— 3 e. f c?. Pes V dext ; the endopodite in anterior view ; x 200.

— 3 f . fj". Portion of pes V in anterior view; x 200.

— 3 g. Pes IV sin. of stage I V in anterior view; x 77. l

— 3 h. Pes IV sin. of stage III in anterior view; x 77. ■

Fig. 4. Gaetanus minor Farran.
Fig. 4 a. f$. The abdomen seen from the left side; x 44.

Fig. 5. Gaetanus latifrons G. O. Sars.

Fig. 5 a. f$. Rostrum and frontal spine; x 24.

— 5 b. f?. Abdomen with spermatophore seen from the left side; x 24.

— 5c. f$. Setae on inner margin of basp. II of pes IV sin. in posterior view; x 117.

— 5d. f$. Oral surface of the labrum; x 280.

— 5 e. f?. Lamina labialis etc.; x 280.

— 5f. Y$ (V). Setae on inner margin of basp. II pes IV sin. in posterior view; x 117.

— 5g- Yc?(V). Same of Yd* (pes IV dext); x 117.

Fig. 6. Gaetanus pileatus Farran.
Fig. 6 a. Labrum in oral view; x 280.

Fig. 7. Gaetanus miles Giesbrecht
Fig. 7 a. The left maxillipes in anterior view; > 77.

— 7b. Setae on inner margin of basp. II of left pes IV in posterior view; x 117.

Plate IV.

Fig. I. Euchirella rostrata Claus.
Fig. I a. f$. Teeth along inner margin of basp. II pes IV dext in posterior view; x 200.

— lb. f?. Labrum in oral view; x 200.

COPEPODA

253

Fig. I c. f$. Lamina labialis etc.; x 200.

— id. f$. Lobus labialis sin.; x 117.

— I e. fd*. Labnim, labium and manducatory portions of the mandibulae seen from beneath; x 117.

— if. fc?. The left pes I in ant. view; x 77.

— I g. fc?. Pes V in ant. view; x 44.

— I h. fc?. The distal segments of the left maxillula; x 117.

Fig. 2. Euchirella messinensis Claus.

Fig. 2a. f^. The labrum in oral view; x 200.

— 2 b. f$. Lamina labialis; x 117.

— 2 c. f$. Area labialis and lobi labiales; x 77.

Fig. 3. Euchirella curticauda Giesbrecht.
Fig. 3 a. f ?. Head; x 24.

Last thoracic and first abdominal somites; x 24.
Labrum in oral view; x 200.
Lamina labialis etc.; x 200.
Lobus labial sin.; x 77.
The frontal portion of the head; x 44.
Abdomen in left view; x 24.
Left maxilla in post, view; x 117.
Fes V in post, view; x 24.
Pes V dextr. Re III; x 117.

The last segment of the exopodite of the left pes V; x 200.

(signature not found on the plate, where the figure is placed to the right of 6 b). The
last segments of the exopodite of the left pes V; x 117.

Fig. 4. Euchirella intermedia u. sp.

Fig. 4a. f$. Abdomen in lateral view; x 22.

— 4 b. f$. Labrum in oral view; x 117.

— 4c. f?. Lobus labialis sin.; x 77.

3 a.

f?.

3 b.

f?.

3 c.

f?.

3d.

f?.

3e.

f?-

3f-

fc?.

3g-

fc?.

3h.

i^.

3i-

fc?.

3J-

fc?.

3l-

fc?.

3 m.

. fc?.

Fig. 5. Euchirella maxima Wolf.

Fig. 5a. f$. The frontal part of the head in lateral view; x 24.

— 5 b. f$. Abdomen in lateral view; x 24.

— 5 c. f ?. The right lateral corner of the last thoracic somite; x 24.

— 5 d. f$. The genital somite of the abdomen seen from below; x 24.

— 5 e. f$. Labrum in oral view; x 77.

— 5 f. f?. Lamina labialis; x 77.

— 5 g. f$. The left lobus labiaHs; x 77.

— 5h. Y(^. The left lateral corner of the last thoracic somite; x 24.

Fig. 6. Undeuchcete superba n. sp.

Fig. 6 a. fc?. Pes V; x 77.
— 6 b. fc?. Pes V dext; x 44.

254 COPEPODA

Plate V.

Fig. I. Undeuchcete superba n. sp.

Fig. I a. The abdomen in right view; x 13-5.

— I b. The left lateral corner of last thoracic somite; x 44.

— I c. Area labialis in ventral view ; x 77.

Fig. 2. Undeuchcete major Giesbrecht
Fig. 2 a. The labrum in oral view ; x 200.

— 2 b. The lamina labialis; x 200.

— 2 c. fc?. The endopodite of the right pes V in anterior and interior view; x 77.

— 2d. fc?. The Re III of left pes V; x 77.

Fig. 3. Undeuchcete minor Giesbrecht.

Fig. 3 a. f $. The genital area from beneath; x jj.

— 3b. f (?. The pes V in anterior view; x 33.

— 3 c. f <?. The endopodite and the exopodite of the right pes V in anterior and interior view; x 77.

— 3d. i,^. The exopodite of the right pes V; x 24.

— 3 e. i<^. The endopodite of the right pes V; x 24.

— 3f. f c?. The Re II— III of the left pes V; x 117.

— 3 §■• f(?- The Re II of the left pes V; x 117.

Fig. 4. Chirudina streetsi Giesbrecht

Fig. 4a. f$. The genital area from beneath; x 77.

— 4b. f$. The labrum in oral view; x 200.

— 4c. f^. The lamina labialis etc.; x 200.

— 4d. f?. The area labialis; x 77.

— 4e. i(^. The pes V in posterior view; x 32.

— 4f. fc?. The 2 last segments of the left pes V in anterior and interior view; x 98.

Fig. 5. Chirudina abyssalis n. sp.

Fig. 5 a. f?. The abdomen seen from the left; x 24.

— 5 b. f$. The left mandibula in ant. view; x 44.

— 5 c. f$. The left maxilla in post, view; x 44.

— 5 d. f$. The marginal teeth of the second basipodite of left pes IV in posterior view; x 117.

— 5 e. f$. The lamina labialis etc.; x 77.

— 5 f. fj. The area labialis; x 77.

Fig. 6. Chirudina pustulifera G. O. Sars.
Fig. 6a. f$. The abdomen in dorsal view; x 24.

— 6b. f J. The first abdominal somite in lateral view; x 24.

— 6 c. f$. The genital area seen from beneath; x 77.

— 6d. f^. The labrum in oral view (anterior portion); x 200.

Fig. 7. Chirudina notacantha G. O. Sars.
Fig. 7 a. fc?. The 2 last segments of the exopodite of the left pes V; x 77.

— 7 b. fd". The last segment of the exopodite of the left pes V from another specimen in a some-

what different position; x 77.

COPEPODA 255

Fig. 8. Chirudina parvispina Farran.
Fig. 8 a. fc?. The 2 last segments of the exopodite of the left pes V; x yj.

Fig. 9. Euchirella bitumida n. sp.

Fig. 9a. f$. The abdomen etc. in dorsal view; x 24.

— 9b. f$. The abdomen seen from the left side; x 24.

— 9 c. f$. The genital somite seen from beneath; x 24.

— gd. f$. The right maxilla in post, view; x 117.

— 9e. f^. The labrnm in oral view (anterior portion); x 200.

— 9 f. f$. The lamina labialis; x 117.

— 9 g. f$. The area labialis; 77.

Plate VI.

Fig. I. Chirudina notacantha G. O. Sars.
Fig. I a. f?. Labrum; x 147.

— lb. f$. L,abiiim ; x 147.

Fig. 2. Valdiviella insignis Farran.
Fig. 2 a. fj. Pes I sin.; outer margin of second and third outer segment in anterior view; x 77.

— 2 b. f$. Anterior surface of the labrum; x 77.

— 2 c. f$. Oral surface of the labrum; x 77.

— 2d. f^. Lamina labialis and serrula 6-dentata; x 77.

— 2 e. f$. Labial lobes etc.; x 77.

Fig. 3. Euchcete norvegica Boeck.

Fig. 3 a. f^. Oral surface of the labrum; x 147.

— 3 b. f$. Lamina labialis; x 147.

— 3 c. f$. Labial lobe; x 147.

— 3d. f<^. Pes V sin.; second and third outer segment; x 77.

— 3 e. f c?. The oral surrounding in ventral view ; x 147.

— 3 f. Y (Stage II). Maxilla sin.; x 'jj.

Fig. 4. Euchcete tonsa Giesbrecht.
Fig. 4a. f$. Labrum in oral view; x 147.

— 4 b. fc?. Pes V sin.; second and third outer segment; x 77.

Fig. 5. Euchcete glacialis H. J. Hansen.
Fig. 5 a. f$. Lamina labialis and serrula 6-dentata; x 147.

— 5b. f?. Labial lobe in ventral view; x 77.
— • 5c. fc?. Maxillula sin.; x 77.

— 5 d. fc?. Pes V sin.; second and third outer segment; x 77.

Fig. 6. Euchcete Farrani n. sp.
Fig. 6 a. f$. Oral surface of the labrum; x 147.

Fig. 7. Euchcete Sarsi Farran.

Fig. 7 a. f$. Labrum in anterior surface; x 57.

— 7 b. fd*. Pes V sin.; second and third outer segment; x 77.

256

COPEPODA

Fig. 8. Euchcete barbata Brady.

Fig. 8 a. f$. Labrum in oral view; x 77.

— 8 b. fd*. Pes V siu.; second and third oiiter segment; x 77.

Fig. 9. Euchcete Bradyi n. sp.
Fig. 9 a. ?. Labruni in oral view ; x 77.

Fig. 10. Euchcete Scotti Farran.
Fig. 10 a. f$. Labrnm in oral view; x 77.

— 10 b. f$. Lamina labialis and serrula 6-dentata; x 77.

— IOC. fd". Pes V sin.; second and third outer segment; x 77.

Fig. II. Euchcete bisinuata Farran.
Fig. II a. f?. Labrnm in oral view; x 147.

— lib. f$. Lamina labialis etc.; 147.

— lie. i^. Maxillipeds; hook-shaped seta of the second basipodite (lobe IV); x 200.

— II d — e. fj". Pes V sin.; third and second outer segment; x 117.

Fig. 12. Euchcete acuta Giesbrecht
Fig. 12 a. f?. Abdomen in lateral view; x 44.

— 12 b. f$. Labrum in oral view; x 200.

— 12 c. f?. Lamina labialis and serrula 6-dentata; x 200.

Fig. 13. Euchcete hebes Giesbrecht.
Fig. 13 a. f$. Abdomen in lateral view; x 44.

— 13b. f$. Lamina labialis and serrula 6-dentata; x 200.

Fig. 14. Scottocalanus Thorii n. sp. (in the plate marked persecans Gbt.)
Fig. 14 a. f^. Labrum in anterior view; x 77.

— 14b. f$. Labrum in oral view; x 117.

— 14c. f$. Lamina labialis and serrula 6-dentata; x 117.

Plate VIL

Fig. I. Phaenna spinifera Claus.
Fig. I a. f $. Rostrum and labrum in anterior view ; x 77.

— lb. f$. Labrum in oral view; x 220.

— I c. f $. Lamina labialis and serrula 6-dentata ; x 280.

Fig. 2. Xanthocalanus pinguis Farran.
Fig. 2 a. f$. Pes V sin. in posterior view; x 77.

— 2b. f$. Labrum in oral view; x 200.

— 2 c. f $. Lamina labialis and serrula 6-dentata; x 200.

— 2d. Y c? (Stags V). Pes V in posterior view ; x 77.

Fig. 3. Xanthocalanus Greeni Farran.
Fig. 3 a. Y J* (V). First inner lobe of the maxillulae in posterior view ; x 44.

— 3b. Yc? (V). Fourth seta in anterior view; x 77.

— 3c. Yc? (V). Maxilla; setae of fifth lobe in posterior view; x 44.

4

i

COPEPODA

257

Fig. 3d. f$. End of broken seta in fifth lobe of the maxillae; x 44.

— 3 e. f?. Maxillipes sin.; x 13-5.

— 3 f. f?. Last segment of left maxillipes; x 44.

— 3 g. f$. Pes II sin.; terminal seta; x 44.

Fig. 4. Cornucalanus chelifer J. C. Thompson.

Fig. 4 a. $. Abdomen in lateral view ; x 13-5.

— 4 b. $. Pes IV sin. in posterior view; x 44.

— 4 c. $. Pes V dext. in posterior view; x 57.

— 4 d. $. Labrum in oral view ; x 280.

— 4 e. $. Serrnla 6-dentata etc. ; x 200.

— 4f. c?. Abdomen in lateral view; x 13-5.

— 4g. <^. Pes V sin.; third onter segment; x 117.

— 4h. $ (Stage V). Pes V sin. in anterior view; x 57.

Fig. 5. Onchocalanus magnus Wolfenden.

Fig. 5 a. ?. Head in lateral view; x 13'5.

— 5 b. $. Abdomen in lateral view; x 13-5.

— 5 c. $. Pes IV sin. in posterior view; x 44.

— 5 d. $. Pes V sin. in anterior view ; x 57.

— 5 e. ?. Labrum in anterior view and labial lobes; x 33.

— 5 f. 5. Labrum in oral view; x 77.

— 5 g. $. Serrula 6-dentata and lobus labialis in anterior view; x 77.

Fig. 6. Onchocalanus cristatus Wolfenden.
Fig. 6 a. ?. Pes V sin. ; third outer segment ; x 57.

— 6 b. c?- Abdomen in lateral view; x 13-5.

— 6 c. c?. Maxilla sin. ; x 44.

— 6d. (?• Serrula 6-dentata; x 200.

— 6e. ? (Stage V). Pes V sin.; x 37.

Fig. 7. Lophothrix frontalis Giesbrecht.
Fig. 7 a. $. Pes III sin.; x 24.

— 7 b. $. Labrum in anterior view; x 117.

— 7c. $. Labrum; oral .surface; x 117.

— 7 d. ?. Lamina labialis and serrula 6-dentata; x 117.

Fig. 8. Scaphocalanus magnus Tli. Scott.
Fig. 8 a. $. Labrum etc. in lateral view ; x 24.

— 8 b. $. Pes II ; endopodite ; x 57.

— 8 c. $. Labrum in anterior view ; x 77.

— 8 d. ^. Labrum in oral view ; x 200.

Fig. 9. Scaphocalanus obtusifrons G. O. Sars.

Fig. 9 a. $. Pes IV dext.; terminal seta; x 77.

— 9 b. $. Labrum in anterior view; x 77.

— go. ?. Labrum in oral view ; x 200.

— 9d. $. Serrula 6-dentata; x 200.

The Ingolf-Expedition. III. 4.

33

258

COPEPODA

Fig. lo. Scaphocalanus globiceps Farran.
Fig. loa. f^. Labrum; oral surface; x 200.

— 10 b. f$. Serrula 6-dentata; x 200.

— IOC. c?. Pes V; x 77. = 11 b.

Fig. II. Scaphocalanus validus Farran.
Fig. II a. f$. Labrum in anterior view; x 77.

— lib. fc?. Pes V of S. globiceps Farran.

Fig. 12. Scaphocalanus robustus G. O. Sars.
Fig. 12 a. f $. Labrum in anterior view; x 200.

— 12 b. f$. Labrum in oral view; x 200.

— 12 c. f$. Serrula 6-dentata etc.; x 200.

Fig. 13. Scolecithricella minor Brady.
Fig. 13 a. f$. Serrula 6-dentata etc.; x 280.

Fig. 14. Scolecithricella ovata Farran.
Fig. 14a. f?. Maxilla sin. in anterior view; x 117.
• — 14 b. f?. Labrum in anterior view and lobi labiales ; x 77.

— 14 c. f?. Labrum in oral view; x 280.

— 14 d. f$. Serrula 6-dentata etc.; x 280.

PI. vm.

Fig. I. Euchirella messinensis Clans.
Fig. I. fd*. Pes I dext in anterior view; x 77.

Fig. 2. Euchirella curticauda GiesbrechL
Fig. 2 a. c?- Pes I sin. in anterior view; x 77.

— 2b. Pes II dext. in anterior view in an abnormal specimen; x 77.

— 2 c. Pes V; right endopodite; x 117.

Fig. 3. Euchirella intermedia n. sp.
Fig. 3. f^. Antenna dextra in anterior view; x 44.

Fig. 4. Euchirella bitumida n. sp.
Fig. 4 a. f?. Head from the left; x 24.

— 4b. f$. Pes I sin. in anterior view; x 77.

— 4c. f$. Pes II dext; endopodite; x 77.

— 4d. f$. Pes III dext.; endopodite; x 77.

— 4e. f$. The first basipodite with spines of the right and left side in posterior view; x 117.

Fig. 5. Chirudina Streetsi Giesbrecht.
Fig. 5 a. ic^. Head from the left; x 24-

— 5 b. i^. Maxilla sin. in anterior view; x 117.

F'ig. 6. Scaphocalanus magnus Th. Scott.
Fig. 6 a. f?. Abdomen from the left; x 24. J

— 6 b. f$. Pes IV sin. in an abnormal siiecimen; x 44. "

COPEPODA

259

Fig. 6 c. f?. Pes V in posterior view in an abnormal specimen; x 77.

— 6d. fj*. Pes V sin.; x 77.

— 6 e. f c?. Pes V dext. ; x 77.

— 6f. Y(^ (V). Abdomen; x 24.

— 6g. Yd'(V). Pes V; x 57.

Fig. 7. Scaphocalanus brevicornis G. O. Sars.
Fig. 7 a. f J*. Abdomen from the left; x 24.

— 7 b. fc?. Pes V; tip of the right endopodite; x 77.

Fig. 8. Scaphocalanus obtusifrons G. O. Sars.
Fig. 8 a. f ?. Abdomen from the left ; x 44.

— 8 b. Pes V. Median portion of the terminal seta; x 200.

— 8 c. fd*. Abdomen from the left; x 44.

— 8d. Yc? (V). Pes V; x 77.

— 8e. Y? (V). Pes V; x 77.

Fig. 9. Scaphocalanus globiceps Farran.

Fig. 9 a. f c?. Pes V dext. in anterior view ; x 77.

— 9b— c. fd*. Pes V dext; endopodite in anterior and lateral view; x 200.

Fig. 10. Scolecithricella minor Brady.
Fig. 10 a. Y?(V). Pes V; x 200.

— lob. Yc? (V). Pes V; x 200.

— IOC Yd* (Stage V). Pes V; x 200.

Fig. II. Scolecithricella Ingolfli n. sp.

Fig. II a. $. Pes IV; third basipodite in anterior view; x 200.

— II b— c. Pes V of two females in anterior view; x 200.

Fig. 12. Scolecithricella ovata Farran.

Fig. 12 a. f$. Head from below; x 77.

— 12 b. f^. Head from the side; x 77.

— 12 c. f$. Genital somite; x 77.

— 12 d. f$. Pes V dext; x 117.

— 12 e. Y$ (Stage V). Pes V in anterior view; x 117.

— 12 f. Y(^ (Stage V). Pes V in anterior view; x 117.

Fig. 13. Scottocalanus securifrons Th. Scott.

F'ig. 13 a. f J". Abdomen from the left; x 20.

— 13 b— c. ic}. Pes V sin. in superior and inferior view; x 77.

Fig. 14. Scottocalanus Thorii n. sp.
Fig. 14 a. fd*. Abdomen from the left; x 20.

— 14 b. f c?. Pes V sin.; x 77.

Fig. 15. Cornucalanus chelifer J. C. Thompson.
Fig. 15 a. f$. Head in lateral view; x 24.

— 15 b. f?. Terminal setae of pes IV sin.; x 117.

— 15c. f$. Pes V sin.; the exopodite; x 200.

33'

26o COPEPODA

Fig. 15 d. fj*. Head; x 24.

— 156. f J". Pes V in anterior view; x •]■].

— 15 f. Y? (V). Abdomen from the left; x 14.

— 15 g. Y c? (V). Pes V in anterior view ; x 57. J

Fig. 16. Onchocalanus magnus Wolfenden.

P'ig. 16 a. f?. Rostrum in anterior view; x 77.

— 16 b. f?. Maxillula sin.; x 44.

— 16 c. f$. Maxilla sin.; x 24.

— 16 d. f$. Pes II; left endopodite; x 57.

I

Eig. 17. Onchocalanus cristatus Wolfenden.

Fig. 17 a. f$. Head from the left; x 14.

— 17 b. f$. Pes II; left endopodite; x 57.

— 17 c. fc?. Head from the left; x 44. ■

— 17 d. fc?. Pes V dext. in anterior view; x 77.

— 17 e. fj*. Pes V sin.; last segment of the exopodite; x 200.

— 17 f. f$. Pes V sin.; x 57.

I

Fig. 18. Xanthocalanus Greeni Farran.
Fig. 18 a. Y? (V). Head from the left; x 14.

— 18 b. Y? (V). Abdomen from the left; x 14.

— 18 c. Y? (V). Pes II; left endopodite; x 44.

— 18 d. Y? (V). Pes V in anterior view; x 44. J

I

I

Tlw Jn<]i>lf Expeditimi M. If.

With : Copcjioda I. Fl ■ L

LCalanusTiJ^perborcus Kt. 2.MacvoealaTmsr>rince-ps Srady. 3.Megacalatms-prirwei>s-Wclf. 4,. Mhincalanus ncunitus Cle.
5. Eucattiniis eUrii/alus Pane. d.E.cMe-Tiualus Dana. IE. crassus Clt . S.Fseudocalanus nunu.lu,s I<r.

.".Clausocalanu.^ arciUfornUs Hcma, . 10. Sptnocaltvixus abyssalis au . ISHoUer se-.

^vn7l- dc-i

The Im^olf Expedition UL ^

With- Copepoda-. I. PI ^■

,ll''l«*>*''

J a

'occk. 2 ChiridiuT obtusifrons G.O.S

3. Ch armalus 5««t. 4 ^^- nasiitus t ^P ■

o.AcMeopsis rostrctc. a.as 7. aaidU.. ir.vu.p.r.u. u.O.S. terua^p ^^^^^ ^^

J. Ch. modes ius n. sp

XVHfL deZ .

The In^olf Expedition IK. j. .

With Copepoda. I. M nc

1. Oatdius brevispvmis ao.S S. &. tenuispinvs ao.S. 3. aaetanus major Wolf, f d viinor T.,rr.
J. a. liUiivoiis ao.S. 6. a. pUe/itus Fa,T. 7. G. miles GU.

Witli JUl.

XMMaUer sc

^

Tfte Jnijolf Expedition M. 4.

With • Copepodti I. Pi. IV.

2i. E. cwiictiwia dsht . ^.K. intcrinrrtin ,1

1 EuchirclliL roslnvta a.i. :i E inc.i^iiiensi.\- cis

A E maxima n yp. o. Undeucluete j-upc;-l>tt n sp

mt/t del

TXliaiel- J&.

The Jn^olf Expedition' M. ^ .

Hi/fy Copepoda I I'l V.

lUndcu-cfuxte superba^ n sp. 2. U. major Gbt. 3U minor Obt ^ Chirudina strMfsi, (itt . Ji r alfT/SjaUs nip.

o. Cpusiuii/cra^ ao.s. 7. Ciioiacuntha ao.S. S. C. parvispina. Farr ii £uc7ureBa, hItumiJa n.sp. rvwiit^r.
'With' -ImI^. ' i.jy.Mouer

fl

^

:<

TIi^ Jngolf Kxprdition M J^.

"■ I - ^^0

Wit/i ropepofJ.j r I'l VL

3^

\

'V

■■;=^^

,>^^J

-^^

; (

r

^

.?/■

JZe-

J.Chirudina notacantha COS. Z Va7dinie.Ua. insi^ms I'a.rr. 3 SuchmU n^i-tfeyioz. Soeck 4 E tons a. abt .

J A,//cicicUis Uans. O.KfurranC nsp. 7. X. i'arsi Tarr. S £ barboAi- Brad- £>. ££radyi. wrp. MlScoiti larr.

II E hi^nuata Fair 12. 1, acuta GM. IS.I.hebe^ 06 1. J^Scottocalofuis persecoms au.

7Jr Holier jc .

With defy

IJie Jm/olf Expedition M 4

8d

J/d

Wiih ■■ fopepoda I. M. W.

With dal.

i.FhtLein,a spiiviUra. as 2Xaj>thocaZani^ pUtyuts Fa.r 3.X.G,-eem Farr. 4Corn.zu-a2aTUl^ cMlifcr man^.
S OTVcA^calanies rnaynus- WoV 6 O cristaxus WM 7 Lop7.ot7,r-ix frorvtalU Git S. Sca^phocOa-rvus moffnus Sc^.

■nns iLas M S. alolriceps .F,^rr- Vf S TaZ-idus Farr. JZ S. roiustuj (LOS.

&. S. oirluji/T-oTU cas. M S.pZohiceps F^rr. // S XaZ-Ldus Farr. JZ S. roiusiuj (LO.S.
13. Scolccithricella. mtrurr SmZ. J4.S.oixUa, farr.

2c^

\'iih: r,<pq'o,i,i I. I'l. Mil .

1 Euchtrella mi:f.finen,nf CIs 2 E curti eauda ait- 3 E intcrmedta n.,p ^E lutiirnid,! nsp. 3 ChiTuJina Strrftsi Ml.
6 SccLpKocalaunus magnum Scoa 7 SbrevicornU aOS. 8.S obtii.pifron.9 aO.-S. 9 S glob ic eps Fam 10 Scolcrillnicella ininnr BiyU,i

llSJngoim n-sp. 12 S.ovatcu Farr 13. Scottoccdanixs securifrotw Scott ^.S.ThorU nsp 15. Cormu-alamis chellfcr nomj,.
Wijji riel. 16 0nchocalanusmajfnMsWolfl70cristatus\\'oir 18.Xanthoca.lanus Gveeni Ijrr.

Tif.iloller sc.

THE INGOLF-EXPEDITION

1895 — 1896.

THE LOCALITIES, DEPTHS, AND BOTTOMTEMPERATURES OF THE STATIONS

Depth

Depth

Depth

Station

Nr.

Lat N.

Long. W.

in
Danish
fathoms

Bottom-
temp.

Station

Nr.

Lat. N.

Long. W.

in
Danish
fathoms

Bottom-
temp.

Station
Nr.

Lat. N.

Long. W.

in
Danish
fathoms

Bottom-
temp.

I

62° 30'

8° 21'

132

7°2

24

63° o6'

56° 00'

1199

2°4

45

61° 32

9° 43'

643

4°i7

2

63° 04'

9° 22'

262

5°3

25

63° 30'

54° 25'

582

3°3

46

61° 32'

11° 36'

720

2°40

3

63° 35'

10° 24'

272

o^'S

63° 51'

53° 03'

136

47

61° 32'

13° 40'

950

3°23

4

64° 07'

11° 12'

237

2°5

26

63° 57'

52° 41'

34

o°6

48

61° 32'

15° II'

1150

3°i7

5

64° 40'

1 2° 09'

155

64° 37'

54° 24'

109

49

62° 07'

15° 07'

1120

2°9I

6

63° 43'

14° 34'

90

7°o

27

64° 54'

55° 10'

393

3°8

50

62° 43'

15° 07'

1020

3°i3

7

63^ 13'

15° 41'

600

4°5

28

65° 14'

55° 42'

420

3°5

51

64° 15'

14° 22'

68

7°32

8

63° 56'

24° 40'

136

6°o

29

65° 34'

54° 31'

68

0°2

52

63° 57'

13° 32'

420

7°87

9

64° iS'

27° 00'

295

5°8

30

66° 50'

54° 28'

22

i°05

53

63° 15'

15° 07'

795

3°o8

ID

64° 24'

28° 50'

788

3°5

3'

66° 35'

55° 54'

88

i°6

54

63° 08'

15° 40'

691

3°9

II

64° 34'

31° 12'

1300

i°6

32

66° 35'

56° 38'

3i8

3°9

55

63° 33'

15° 02'

316

5°9

12

64° 38'

32° 37'

1040

o°3

33

67° 57'

55° 30'

35

o°8

56

64° 00'

15° 09'

68

7°57

13

64° 47'

34° 33'

622

3°o

34

65° 17'

54° 17'

55

57

63° 37'

13° 02'

350

3°4

14

64° 45'

35° 05'

176

4°4

35

65° 16'

55° 05'

362

3°6

58

64° 25'

12° 09'

211

o°8

15

66° 18'

25° 59'

330

-o°75

36

61° 50'

56° 21'

1435

i°5

59

65° 00'

11° 16'

310

-o°i

i6

65° 43'

26° 58'

250

6° I

37

60° 17'

54° 05'

1715

i°4

60

6s° 09'

12° 27'

124

o°9

17

62° 49'

26° 55'

745

3°4

38

59° 12'

51° 05'

1870

i°3

61

65° 03'

13° 06'

55

o°4

i8

61° 44'

30° 29'

1 135

3°o

39

62° 00'

22° 38'

865

2°9

62

63° 18'

19° 12'

72

7°92

19

60° 29'

34° 14'

1566

2°4

40

62° 00'

21° 36'

845

3°3

63

62° 40'

19° 05'

800

4°o

20

58° 20'

40° 48'

1695

i°5

41

61° 39'

17° 10

1245

2°0

64

62° 06'

19° 00'

1041

3°i

21

58° 01'

44° 45'

1330

2°4

42

61° 41'

10° 17'

625

o°4

65

61° 33'

19° 00'

1089

3°o

22

58° 10'

48° 25'

1845

i°4

43

61° 42'

10° 11'

645

o°o5

66

61° 33'

20° 43'

1128

3°3

23

60° 43'

56° 00'

Only the

Plankton- Net

aaed

44

61° 42'

9° 36'

545

4°8

67

61° 30'

22° 30'

975

3°o

station

Nr.

Lat. N.

Long.W.

Depth

in
Danish
fathoms

Bottom-
temp.

Station

Nr.

Lat. N.

Long. W.

Depth

in
Danish
fathoms

Bottom-
temp.

station

Nr.

Lat. N.

Long. \V.

Depth

in
Danish
fathoms

Bottom-
temp.

68

62° 06'

22° 30'

843

3°4

92

64° 44'

32° 52'

976

i°4

1

118

68° 27'

8° 20'

lo6o

— i°o

69

62° 40'

22° 17'

589

3°9

93

64° 24'

35° 14'

767

i°46

119

67° 53'

10° 19'

lOIO

— i°o

70

63° 09'

22° 05'

134

7°o

94

64" 56'

36° 19'

204

4° I

120

67° 29'

II°32'

885

- i°o

71

63046'

22° 03'

46

65° 31'

30° 45'

213

121

66° 59-

13° II-

529

-o°7

72

63° 12'

23° 04'

197

6°7

95

65° 14'

30° 39'

752

2°I

122

66° 42'

14° 44'

115

i°8

73

62° 58'

23° 28'

486

5°5

96

65° 24'

29° 00'

735

.°2

123

66° 52'

15° 40'

145

2°0

74

62° 17'

24° 36'

695

4°2

97

65° 28'

27° 39'

450

5°5

124

67° 40'

15° 40'

495

-o°6

61° 57'

25° 35'

761

98

65° 38'

26° 27'

1 38

5°9

125

68° 08'

16° 02'

729

-o°8

61° 28'

25° 06'

829

99

66° 13'

25° 53'

187

6°i

126

67° 19'

15° 52'

293

-o°5

75

61° 28'

26° 25'

780

4°3

100

66° 23'

14° 02'

59

o°4

127

66° 33'

20= 05'

44

5°6

76

60- 50'

26° 50'

806

4° I

lOI

66° 23'

12° 05'

537

-o°7

128

66° 50'

20° 02'

194

o°6

77

60° lO'

26-59'

951

306

102

66° 23'

10° 26'

750

-o°9

129

66° 35'

23° 47'

117

6°5

78

60° 37'

27° 52'

799

4°5

103

66° 23'

8° 52'

579

o°6

130

63° oo'

20° 40'

338

6°55

79

60° 52'

28° 58'

653

4°4

104

66° 23'

7° 25'

957

— i°i

131

63° oo'

19° 09'

698

4°7

80

61° 02'

29° 32'

935

4°o

105

65° 34'

7° 31'

762

— o°8

132

63° 00'

17° 04'

747

4°6

81

61° 44'

27° 00'

485

6°!

106

65° 34'

8° 54'

447

-0=6

133

63° 14'

11° 24'

230

2°2

82

61° 55'

27° 28'

824

4°i

65° 29'

8° 40'

466

134

62° 34'

10° 26'

299

4° I

83

62° 25'

28° 30-

912

3°5

107

65° 33'

10° 28'

492

-o°3

135

62° 48'

9° 48'

270

o°4

62° 36-

26° 01'

472

108

65° 30'

12° 00'

97

i°i

136

63° 01'

9°:i-

256

4°8

62° 36'

25° 30'

401

109

65° 29'

13° 25'

38

i°5

137

63^ 14'

8° 31'

297

— o°6

84

62° 58'

25° 24'

633

4°8

no

66° 44'

11° 33'

781

— o°8

138

63° 26'

7° 56'

471

-o°6

85

63° 21'

25° 21'

170

III

67° 14'

8° 48'

860

-o°9

139

63'' 36'

7°30-

702

-o°6

86

65° 03-6

23° 47'6

76

112

67° 57'

6° 44'

1267

— i°i

140

63° 29'

6° 57'

780

-o°9

87

65° 02-3

23° 56'.

no

113

69° 31'

7° 06'

1309

— i°o

141

63° 22'

6° 58'

679

-o°6

88

64° 58'

24° 25'

76

6°9

114

70° 36'

7° 29'

773

— i°o

142

63° 07'

7°o5'

5S7

-o°6

89

64° 45'

27° 20'

310

8°4

"5

70° 50'

8° 29'

86

o°i

143

62° 58'

7° 09'

388

-o°4

90

64° 45'

29° 06'

568

4°4

116

70° 05'

8° 26'

371

-o°4

144

62° 49'

7=" 12'

276

i°6

91

64° 44'

31'= 00'

1236

3°i

117

69° 13'

8°23-

1003

- i°o

••C^®$3— —

THE DANISH INGOLF-EXPEDITION.

HITHERTO PUBLISHED:

1899. Vol. I, Part I. I. Report of the Voyage by C. F. IVandel (i plate)

2. Hydrogjaphy by Martin Knudsen (34 plates)

1900. — Part II. 3. The deposits of the sea-bottom by O. B. Boeggild

(7 charts)

4. Current-bottles by C. F. Wandcl (i plate)

1899. Vol. II, Part I. The ichthyological results by Chr. Liitkcn (4 plates) . . .

1899. — Part II. On the Appendices genitales (Claspers) in the Greenland-

Shark, Somniosus microcephalus (Bl. Schn.), and other Sela-
chians by Hector F. E. Jungersen (6 plates)

1900. — Part III. Nudibrauchiate Gasteropoda by R. Bcrgh (5 plates)...
1904. — Part IV. The North-European and Greenland Lycodinse by

Adolf Severin Jensen (10 plates)

1912. — Part V. Laniellibranchiata, Part I, by Ad. S. Jensen. (4 plates

and 5 figures in the text)

1899. Vol. Ill, Part I. Pycuogonidse by Fr. Meinert (5 plates)

1908. — Part II. Crustacea Malacostraca, I: Decapoda, Euphausiacea,

Mysidacea b\- H. J. Hansen (5 plates)

1913. — Part III. Crustacea Malacostraca, II: Tanaidacea by H.J. Hansen

(12 platesi

191 5. — Part IV. Copepoda I. Calanoida. Amphascandria by Carl With.
(8 plates, 422 textfigures) •

1903. Vol. IV, Part I. Echinoidea, Part I, by Th. Mortensen (21 plates)

1907. — Part n. Echinoidea, Part II, by Th. Mortensen (19 plates)

1914. — Part III. Chaetoguaths by R. von Ritter-Zahony

1904. Vol. V, Part I. Pennatulida by Hector F. E. Jungersen (3 plates)

1912. — Part II. Ctenopliora by Th. Mortensen (10 plates and 15 figures

in the te.xt)

1912. — Part III. Ceriantharia by Oskar Carlgren (5 plates and 16 figures

in the text)

1913. — Part IV. Zoautharia by Oskar Carlgren (7 plates and 6 figures

in the text)

1914. — Part V. Stylasteridae by H/alinar Broch (5 plates and 7 figures

in the text) .'

1902. Vol. VI, Part I. Porifera (Part i), Homorrhaphidse and Heterorrhaphidae
by Will. Lundheck (19 plates)

1905. — Part II. Porifera (Part 2), Desmacidonidse (Pars) by H>^/7/.Z2<«<//5^^-t

(20 plates)

1901. — Part III. Porifera (Part 3), Desmacidonidae (Pars) by Will. Lundbeck

(I I plates)

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