REPORT

V.l

K

OF THE

CANADIAN ARCTIC EXPEDITION

1913-18

VOLUME VII: CRUSTACEA

PART K: MARINE COPEPODA

By ARTHUR WILLKY

Vol. vii-6f'096

OTTAWA

THOMAS MULVEY

PRINTER TO THE KING'S MOST EXCELLENT MAJESTY
1920

Issued June 25, 1920

Report of the Canadian Arctic Expedition 1913-18.

VOLUME VII : CRUSTACEA.

Part A: DECAPOD CRUSTACEANS. By Mary J. Rathbun (Issued August 18, 1919}.

Part B: SCHIZOPOD CRUSTACEANS. By Waldo L. Schmitt . (Issued September 22, 1919).

Part C: CUMACEA. By W. T. Caiman (In press}.

Part D: ISOPODA. By Miss P. L. Boone (In press).

Part E: AMPHIPODA. By Clarence R. Shoemaker (In press).

Part F: PYCNOGONIDA. Leon J. Cole '(In press).

Part G: EUPHYLLOPODA. By F. Johansen (In preparation).

Part H: CLADOCERA. By Chancey Juday (In press).

Part I : OSTRACODA. By R. W. Sharpe. , (In preparation).

Part J : FRESHWATER COPEPODA. By C. Dwight Marsh (Issued April 21, 1920).

Part K: MARINE COPEPODA. By A. Willey (Issued 1920).

Part L: PARASITIC COPEPODA. By Charles B. Wilson (In press).

Part M: CIRRIPEDIA. By E[. A. Pilsbry. . (In preparation).

REPORT

OF THE

CANADIAN ARCTIC EXPEDITION

1913-18

VOLUME VII: CRUSTACEA

PART K: MARINE COPEPODA

By ARTHUR WILLEY

OTTAWA

THOMAS MULVEY
PRINTER TO THE KING'S MOST EXCELLENT MAJESTY

1920
Vol. vii— 69385— 1 Issued June 25,, 1920

Report on the Marine Copeppda collected during the Cana-
dian Arctic Expedition.

BY ARTHUR WILLEY, D.Sc., F.R.S.

McGill University, Montreal.

The marine copepod Crustacea, collected by Mr. Frits Johansen during the
Canadian Arctic Expedition from 1913 to 1916, covers a wide extent of coast-
line from Vancouver island to Coronation gulf in the Northwest Territories of
Canada, the whole embracing an area which has been only slightly explored
in regard to its micro-crustacean fauna. The comparison of this fauna with
that of the Atlantic coast of North America offers remarkable similarities mingled
with dissimilarities, as indeed does every other division of the North Pacific
fauna. The facts discovered justify the expectation that further data wiH
throw light upon the relation of the pelagic copepods to the currents prevailing
off the west coast. These insignificant arthropods form the basis of the food-
supply for pelagic fishes, especially for young fishes, whilst the littoral and
bottom-dwelling species have nutritive value for the flat-fishes, either directly
or indirectly.

The copepod contents of Mr. Johansen's samples were generally scanty,
so that it was not always possible to indicate their percentage composition.
In the present report several species are identified for the first time from the
west and northwest coasts, but perhaps the most memorable marine copepod
record for the entire expedition is that of Limnocalanus grimaldii from Collinson
point, Alaska. It will be found that the collection secured by Mr. Johansen
under such arduous circumstances presents several other features of interest.
A notable deficiency is the absence, from all the gatherings, of Calanus cristatus
which, according to Giesbrecht, is the most characteristic species of the Behring
sea and has not been found south of that area. The explanation of its
absence is to be looked for in the comparatively small number of stations made
by the expedition on the voyage to the Arctic Ocean where their main
objective lay.1

The number of copepods of the subdivision Harpacticoida taken pelagically
by horizontal towing of the plankton nets at or near the surface, in water lanes
amid pack-ice, or by vertical hauls through holes in the ice, makes a rather
striking commentary on this collection. Just as the pelagic Calanoids make
daily excursions to and from the deeper strata of water, so the benthonic or
bottom-dwelling Harpacticoids evidently rise toward the surface from time
to time. Only one pelagic Harpacticoid was recorded from the east coast waters
during the Canadian Fisheries Expedition, 1914-15, namely, Halithalestris croni.
This species has not yet been found on the west coast. The clear-cut specific
divergence of Danielssenia stefanssoni, in comparison with its Siberian congener,
is another point worthy of special mention.

A. CALANOIDA.
1. Calanus finmarchicus (Gunnerus, 1765).

This prolific species is common to the North Pacific, North Atlantic, and
Arctic oceans. According to the latitude, season, time, depth, and proximity
to land or ice, in which it may be taken, it is found associated with very different
companions.

1NoTE. — Most of the macroscopic forms in the Zooplankton (Fishes, Crustacea, Annelids, Medusae,
etc.), were picked out before the samples were sent to Prof. Willey. — Frits Johansen.
69085— 1|

4 K Canadian Arctic Expedition, 1913-18

Stations 18a,c,e,/,: 62° N., 167° 30' W., four gatherings with net No. 31,
towing at surface for 5, 10, and 15 minutes, preserved in one vial, July 7, 1913.
The quantity was small for the time employed in towing. It may be called an
Acartia-plsiiikton, since that genus was in the ascendant. There were also more
than one hundred young Amphipods (Hyperidea), twenty-four crab larvae
(Zoese), and a few fish-larvae.

The following century of copepods, exclusive of the Acartia, was made out :—

TABLE I (STA. 18, EXCL. ACARTIA).

Calanus finmarchicus d", 3 • 75 mm

Pseudocalanus elongatus >

Centropages mcmurrichi 9 1

Eurytemora herdmani (d" and 9 )

Paralabidocera amphitrites (all young) -VJ

Tortanus discaudatus 9

100

Station 21a, 6, c: 68°30' N., 166° 32' W., temperature 45.6° F., August
15, 1913. Three gatherings of five minutes each at surface, with net No. 22,
yielded a fairly copious plankton of small Cladocera (Evadne and Podon),
Molluscan larvae, Annelid larvae, Medusae, 1 crab-larva (Megalopoda), young
Amphipoda and some Copepods (table II). The station lies north of Bering
strait, but south of the Arctic circle. The composition of the gathering
indicates current action through the narrow strait.

TABLE II (STA. 21a, b, c).

Calanus finmarchicus, stages IV and V

Pseudocalanus elongatus (chiefly 9 ) 25

Centropages mcmurrichi

Paralabidocera amphitrites (d" and 9 )

Eurytemora herdmani (chiefly d")

Eurytemora johanseni (<? and 9 )

Acartia longiremis 10

Acartia clausi 10

Oithona similis 2

100

Station 256, c: off Cooper island (point Barrow), Alaska, within the Arctic
circle; depth two fathoms; August 27 and 28, 1913. Two gatherings of ten
minutes each with net No. 3, at surface among ice, contained some very young
Calanus.

TABLE III (STA. 256, c).

Calanus finmarchicus I

Calanus finmarchicus II 3

Calanus finmarchicus III 2

Calanus finmarchicus IV 2

Pseudocalanus elongatus 24

Acartia (clausi and longiremis) 60

Oithona similis 3

Harpacticus (immature) 2

Danielssenia fusiformis 1

100

Station 27r: Collinson point (Camden bay), Arctic Alaska; depth 1 to 2
fathoms; October 2, 1913. A short haul with catcher3 from one fathom to the
surface, under ice ten inches thick, captured a male of Metridia longa in company
with C. finmarchicus V, and young Pseudocalanus.

1 This plankton net was made'of coarser silk, closed at the end, nine inches wide at the mouth, twenty
inches long.

2 Full-speed net of fine silk, two inches across mouth, two feet long, with bottle at end.

3 See footnote p. 6 K.

Marine Copepoda 5 K

Station 27 t, u: same locality and depth as preceding, October 4 and 5, 1913.
The following assemblage (table IV) was taken through a crack in the ice, one
to two feet below the surface, with net No. 3: —

TABLE IV (STA. 27 1, u).

Calanus finmarchicus IV, V and 9 ( 10

Calanus hyperboreus IV and V 4

Pseudocalanus elongatus > . . . 54

Limnocalanus grimaldii (<? and 9 ) 10

Oithona similis 20

Onccea conifera 2

100

In addition there was an Ectinosoma, a Pseudobradya and an Acartia. The

presence at this station of Limnocalanus is of particular interest, as will be detailed

more fully below. One C. finmarchicus 9 measured 4.25 mm., another 4.5 mm.

Station 27y2: Entrance of lagoon at Collinson point; depth 1 to 2 feet

inward current, no ice, net No. 3, fifteen minutes, October 8, 1913.

TABLE V (STA. 27y#).

Calanus finmarchicus IV 1

Calanus finmarchicus V 7

Calanus finmarchicus 9 1

Calanus hyperboreus V 1

Pseudocalanus elongatus III 10

Pseudocalanus elongatus IV . 20

Pseudocalanus elongatus V '. 30

Pseudocalanus elongatus 9 10

Gaidius (immature) 10

Oithona similis . . 10

100

Station 29e: 70° 3' N., 141° W., depth 25 fathoms, April 2, 1914. Three
vertical hauls with net No. 3, from 0-20 fathoms, through crack in ice, yielded
one C. finmarchicus 9 and two or three immature male Pseudocalanus.

Station 290: 70° 20' N., 140° 30' W., depth 150 fathoms, April 6, 1914.
Several vertical hauls were made, at various depths with plankton net number
51 through cracks in the ice. The captures comprised C. finmarchicus, young
and adult, including a female of 5-5 mm., and a male of 4-5 mm., in company
with Calanus hyperboreus, Pseudocalanus elongatus, Euchaeta norvegica (see
below), Metridia longa and Oithona similis.

Station 41s: Bernard harbour (inner harbour), Dolphin and Union strait,
temperature 35-3° F., net No. 3, ten minutes at surface, August 24, 1915.

TABLE VI (STA. 41s).

Calanus finmarchicus I-V 22

Calanus hyperboreus V 1

Pseudocalanus elongatus 60

Eurytemora herdmani 2

Oithona similis 12

Idycea furcata 1

Danielssenia stefanssoni 2

100

The absence of adult Calanus is to be noticed. One Eurytemora carried
an ovisac. The C. hyperboreus V (the stage preceding maturity) measured
6 mm. in length and the fifth foot had 15 coxal teeth. One C. finmarchicus V
of 4 mm., had 28 coxal teeth at the base of the fifth foot. At stage 1 there are

1 Vertical net, 12 inches across mouth, end open 3 inches wide, with brass bucket and silk-net bottom;
length 3| feet, the upper half made of canvas.

(JK The Canadian Arctic Expedition, 1913-18

two pairs of swimming feet; at stage II, three pairs; at stage III, four pairs.
One C. finmarchicus II was 1-52 mm. long; and one of stage IV measured 3-5
mm.

Station 43e: Dolphin and Union strait, off Stapylton bay, depth about 25
fathoms, net No. 3, ten minutes at surface, September 14, 1915. The material
contained a quantity of phytoplankton and copepod pupae, the latter dominating
the zooplankton. Fritillaria and Pluteus were also present. The air temper-
ature was 23° F., and the water temperature 30-8° F.

TABLE VII (STA. 43e).

Calanus finmarchicus I

Pseudocalanus elongatus 9

Pseudocalanus elongatus 9 juv 12

Pseudocalanus elongatustf juv 20

Eurytemora herdmani 9

Eurytemora herdmani d* 5

Acartia longiremis 9

Acartia longiremistf 16

Oithona similis 20

Amphiascus nasutus o" 1

100

Station 57a: Cape Smyth (point Barrow), Alaska, depth 3 fathoms, August
8, 1916; secured by the catcher1: —

Calanus finmarchicus IV 1

Calanus finmarchicus V 2

Calanus finmarchicus 9 2

2. Calanus hyperboreus Kroyer, 1838.

Besides the occurrences of this species noted in Tables IV, V and VI, there
are several other records to be mentioned.

Station 27yl: Lagoon at Collinson point Alaska, in 1-2 feet of water, no
ice, October 8, 1913, catcher. One C. hyperboreus V, length 5-6 mm. The
lateral lobes of the last thoracic segment were triangular and bluntly pointed,
so that doubt might be entertained about its identification until the fifth legs,
with 17 coxal teeth, were examined. The inner and outer branches of the fifth
legs were 2-jointed; the remaining natatory legs had both rami 3-jointed. The
anterior antennae were 25-jointed, joints 8 and 9 being feebly separated.

Station 286: Collinson point, Alaska, depth one fathom, ice 12 inches thick,
'October 14, 1913, catcher. One C. hyperboreus IV, length 4-7 mm. was taken
The abdomen was three-jointed; p 5 Re and Hi, one-jointed; the remaining
legs had two-jointed rami. The jointing of the antenna? and mouth-parts was
the same as in the adult, joints 8 and 9 of the anterior antenna? being imperfectly
divided.

Station 28e: Same locality, ice 16 inches thick, October 21, 1913. One
female of 8 mm. was taken in the catcher.

Station 2903: 70° 20' N., 140° 30' W., depth 150 fathoms; vertical haul
with net number 5 from 50 to 150 fathoms, April 6, 1914. Two mature females
measuring 7-5 and 8-5 mm. in length.

Station 30a: 69° 41' N., 141° 11' W., off Demarcation point, Alaska, about
300 yards offshore, depth 3 fathoms, May 4, 1914. Six vertical hauls with
net number 3, from surface to bottom, through a hole in the ice which was six
feet thick. The total number of copepods preserved was 74, distributed as under.

1 The bag of the catcher was made of bobinette, having wider meshes than any of the plankton nets

Marine Copepoda 7 K

TABLE VIII (SrA. 30a).

Calanus hyperboreus IV 1

Pseudocalanus elongatus III 1

Pseudocalanus elongatus IV 7

Pseudocalanus elongatus V 42

Pseudocalanus elongatus 9 11

Pseudocalanus elongatus rf1 5

Oithona similis 5

Onccea conifera 1

Harpacticus superflexus 1

74

Station 41p: Bernard harbour, Dolphin and Union Strait, Northwest
Territories, beach water, in the catcher, August 14, 1915. One female 8-25
mm. long without the fan of caudal setae, 10 mm. long including the caudal
setae. A coloured drawing by Mr. Johansen shows the body nearly uniformly
red, the anterior antennae deep red.

Station 41w: Bernard harbour, end of August, 1915. Four mature females
were taken from the stomach of a Western Charr or Dolly Varden trout, Salve-
linus malma, W. I wrote about this interesting find to Mr. Johansen who
kindly informed me that practically all the specimens of the Dolly Varden trout
which he obtained in the north were caught in salt water. A large lake east of
Bernard harbour, contained individuals which had not succeeded in getting
back to the sea before the creek froze up, so that they had to stay in the lake
for the winter.

3. Calanus tonsus Brady.
G. S. Brady: Report on the Copepoda. Challenger Rep,, vol. VIII, p. 34, 1883.

This is a normal-looking Calanus, like C. finmarchicus, but characterized
by the absence of basal serratures on the fifth pair of legs. It was taken by
the Challenger Expedition chiefly in the southern hemisphere but also, in com-
pany with Calanus propinquus Brady, in the surface tow-net at station 241,
between Yokohama and Sandwich islands, over a depth of 2,300 fathoms in
lat. 35° 41' N., long. 157° 42' E.

Three damaged specimens of C. tonsus, stage V, were contained in the
gathering from C. A. E. station 13a, b, c, three surface tows of five minutes
each, lat. 54° 30' N., long. 159° 42' W., July 1, 1913. The gathering was scanty
but included Acartia tumida n. sp., Acartia longiremis, and Harpacticus uniremis.

C. tonsus was the species referred to without name in my report on an
investigation into the Pacific Halibut Fisheries.1 I saw numbers of them in an
inlet to the south of Tassoo harbour, on the west coast of Moresby island, south
of the San Christoval mountains, Queen Charlotte islands. In the evening
of May 22, 1914, "they were rising to the surface amongst the kelp, one by one,
then swimming round in spirals, clockwise, causing distinct widening ripples
at the surface." These were also immature. From the peculiar distribution
of this species it may be anticipated that future investigations will disclose a
special connection with oceanic currents.

Published in the Canadian Bluebook: Contributions to Canadian Biology (1914), Ottawa, 1916.

SK Canadian Arctic Expedition, 1913-18

4. Pseudocalanus elongatus (Boeck, 1864).

This species shares with Acartia the quality of being the most abundantly
represented in Mr. Johansen's gatherings. In addition to the stations tabulated
above, the following have to be added.

Station 130, h: 54° 30' N., 159° 42' W., two surface tows of 15 and :*<)
minutes, net number 3, July 1, 1913. The gathering was very scanty, a female
Pseudocalanus being present, together with traces of Metridia, Acartia, Har-
pacticus, and Cypris-l&rvsd of Cirripedes.

Station 20a: Grantley harbour, Alaska; depth two fathoms, surface tow
.") minutes, net number 3, July 30, 1913. This was a Cladoceran plankton,
numerous Evadne and Podon, with strong copepod infiltration, and some Mollus-
ran and Annelid larvae. Acartia clausi was almost as abundant as were the
Cladocera.

TABLE IX (STA. 20a).

I'm udocalanus elongatus, scarce; o", 9 and young.
Centropages mcmurrichi, abundant; 9 and somecf.
Eurytemora herdmani, two ovigerous females.
Eurytemora johanseni, males only noted.
Acartia clausi, very abundant.
Tortanus discaudatus, one female.
Idycea furcata, one female.

Station 40d: Bernard harbour, water depth 9 fathoms, six. vertical hauls
0-5 fathoms with net number 3 through hole in ice, June 8, 1915. Female and
immature male, the latter with four-jointed urosome but anterior antennae
19-jointed as in adult male.

Station 42p: Bernard harbour (outer harbour), surface tow with net
number 3 for 10 minutes, September 30, 1915. The scanty gathering included
a few Pseudocalanus, mostly young. There were also present: Eurytemora
herdmani <?, Oithona similis, Harpacticus uniremis, Idycea furcata, Danielssenia
stefanssoni.

Station 42y: Dolphin and Union strait, off Bernard harbour, depth 17
feet; ice 2J feet thick, December 6, 1915, time noon. Six vertical hauls from sur-
face to bottom were taken with net number 3 at low tide with an eastward
current. There were upwards of 100 small copepods. The Pseudocalanus
were of various ages, abdomen two to fourjointed, all immature.

TABLE X (STA. 42y).

Pseudocalanus elongatus . . .'. 40

Metridia longa , 8

Acartia longiremis 2

Oithona similis 38

Onccea conifera 2

Idycea furcata 10

100

Station 422: Same locality and depth as preceding; time midnight; three
vertical hauls with net number 3 from bottom to surface through hole in ice;
water temperature 29-2° F., December 12, 1915. Both males and females were
taken, in company with Idycea furcata, Metridia longa, Acartia longiremis, Oncaea
conifera and Thaumaleus bernardensis.

A female Pseudocalanus from station 27t, u, (above table IV) had a two-
chambered cyst attached to the right anterior antenna, with faint indication
of radial arrangement of the brown granular contents (Fig. 1). Similar parasites,
questionably assigned to the Infusoria, were observed and figured upon Calanus

Marine Copepoda 9 K

finmarchicus by T. Scott [15th Ann. Rep. Fishery Board, Scotland 1896 (1897)
p. 172, pi. Ill, f. 22.] They are now believed to belong to the Peridinea and
have been named Ellobiopsis chattoni by Professor Maurice Caullery.1

Fig. 1. Portion of right antenna of Pseudocalanus from Collinson point
with Ellobiopsis chattoni Caullery attached to it.

According to Carl With (Copepoda I. Danish Ingolf Exped., vol. Ill, part
4, p. 57, Copenhagen 1915) this long established species should be known in
future as Pseudocalanus minutus (Kroyer 1845-47).

5. Gaidius sp. juv.

Only immature examples of this form occurred in the gathering from station
27y2 (above, table V). They were mostly immature males. Front obtuse,
rostrum obsolescent or absent; length of immature d1, 1-92 mm.; fifth feet of
immature male biramous .(Fig. 2).

Fig. 2. Gaidius immature d", abdomen 4-jointed.
R. Right fifth leg.
L. Left fifth leg.

I had at first entered them in my list as Chiridius obtusifrons because of
the absence of a rostrum and the presence of short lateral acuminations of the
last thoracic segment. The male of Aetideus armatus is likewise devoid of a
rostrum, but according to Sars this species has never been found anywhere in

1 M. Caullery (Paris): Sur un parasite de Calanus helgolandicus Glaus, appartenant probablement aux
Peridiniens (Ellobiopsis chattoni n.g., n.sp.). Verh. VIII, Internat. Zpol. Kongresses zu Graz 1910, Jena
1911, pp. 440-442. The complete description appeared in Bulletin scient. France, Belgique, t. 44, 1910,
fasc. 3, 201-214, pi. V.

10 K Canadian Arctic Expedition, 1918-18

the Arctic ocean, and the adult male is only 1-45 mm. long. Aside from the
presence or absence of a rostrum, the Canadian Arctic forms agree with Gaidius
tenuispinus in having the inner branch (Ri) of the second legs (p.2) two-jointed
and in lacking an outer seta (se) on the first joint of the outer branch (Re 1) of
the first legs (p. 1). Sars observed that G. tenuispinus sometimes occurs in the
same gatherings with Ch. obtusifrons, both species ranging through the Polar
basin crossed by Nansen.

The inner ramus of the mandibular palp is not so "unusually small" as is
required by the definition of Chiridius; the teeth of the mandible have simple
points. The anterior antennae are 24-jointed, joints 8 and 9 being coalescent,
the terminal joint distinct and short; the entire appendage is not longer than
the forebody. The second basal joint (B2) of the second maxilliped (mp2) is
hardly longer than the Bl ; the first inner seta (si) of B2 is inserted distad of the
middle of the joint, the portions of the joint proximal and distal to the insertion
of this seta being as 2: 1.

6. Euchaeta norvegica Boeck, 1872.

I noted only a single damaged immature female, with three-jointed abdomen,
in the gathering from station 2904, depth 150 fathoms; a vertical haul with net
number 5 from 0 to 50 fathoms in an open water lane in pack-ice, 70° 20' N.,
140° 30' W. There was a very small quantity of plankton for such a great
column of water. In the same vial with the Euchaeta there was one Metridia
longa 9, and half a dozen Oithona similis.

Euchaeta norvegica is a characteristic North Atlantic and Arctic species.
It occurred at numerous stations in Dr. Hjort's Canadian Fisheries Expedition
19 14-1 5, L but not in Professor Herdman's traverses of the Atlantic to which
reference will be made later. At Passamaquoddy Bay it forms part of the food
of the Pollack.

7. Centropages mcmurrichi, n. sp.

This species occurred at several stations already mentioned: Tables I,

11 and IX. It was first obtained off the British Columbian coast by Professor
J. Playfair McMurrich2 in a patch of "brown water" off the entrance to Esperanza
inlet , on the west coast of Vancouver island on September 11, 1912. He identi-
fied it as Centropages hamatus (Lilljeborg 1853), whilst noting differences in the
armature of the genital segment of the female and in the structure of the fifth
legs. It has the ventral recurved hook of C. hamatus 9 in front of the genital
pore but the remaining setulose armature of the genital segment is distinctive.
The other principal specific character is afforded by the strong unguiform process
on the inner side of the second joint of the outer ramus of the fifth foot (p5 Re2 9 ).
In C. hamatus this process is smooth and less than half the length of the third
joint (p5 Re3). In the present species the process is at least two-thirds the
length of Re3 and is denticulated along its outer edge. The relative dimensions
of anal segment and caudal furca in the female are: anal segment 6, furcal
length 11, width of furcal ramus 3.

In addition to the stations named above, a single female, accompanied by
numbers of Paralabidocera, was taken at station 21 d, e,f, with net number 3, 68°
41' N., 165° 10' W., temperature 45-5° F., surface, August 16, 1913. Afemale
from station 20a, July 30, 1916 (Table IX) carried a spermatophore.

The spinules on the genital segment of the female include a pair of antero-
ventral groups arranged in a comb-like row right and left of the swollen base

1 A. Willey: Report on the Copepoda obtained in the Gulf of St. Lawrence and adjacent waters 1915.
Canad. Fish. Exped. 1914-1915. Department of the Naval Service Bluebook, pp. 173-220, Ottawa 1919.

1 J. P. McMurrich: Notes on the Plankton of the British Columbia Coast. Trans. Roy. Soc. Canada
(ser. Ill), vol. X, September, 1916, p. 77-8, f. 1-3.

Marine Copepoda UK

of the hook; a right lateral comb-like group of strong spinules near the middle
of the segment and a left postero-lateral group of much smaller spinules near
the posterior end of the segment; also right and left dorso-lateral tufts in the
anterior region. The segment itself and the groups of spinules are asymmetrical.

8. Limnocalanus grimaldii (J. de Guerne, 1886).

This noteworthy species occurred in one gathering only, at station 27
t, u, Collinson point, Alaska, October 4 and 5, 1913, forming 10 per cent of
the copepod content (table IV). The lateral edges of the last thoracic segment
(Th5) have an acute point set in the middle of the border and do not taper to
the point; total length of female 2-85 mm. The caudal furca is long, two-fifths
the total length of the urosome; the upper and lower surf aces of the caudal rami
are beset with short spines, the inner and outer surfaces are setulose (or
"ciliated")- Abdomen of female three-jointed; of male five-jointed, with spines
on dorsal and ventral borders of Ab 2, 3, and 4. Right geniculate antenna of
male with five joints beyond the bend, the first of which is long, the last very
small.

It has perhaps the most remarkable distribution of any marine copepod.
It was first taken in the Gulf of Finland and named in honour of Prince Albert
of Monaco by J. de Guerne in 1886. Two years later it was declared by Nord-
quist1 to be identical with Limnocalanus macrurus G. O. Sars 1862 from the
Scandinavian lakes. Its validity as a species distinct from the freshwater form
was proved by G. 0. Sars who found it in material from the Caspian Sea, where
it constitutes part of the relict glacial fauna of that basin.2

The same species (L. grimaldii} was recorded by Sars living pelagically
in the estuary of the river Jana in Siberia. The length of female examples
from Siberia was 3.30 mm., as against 2-80 mm. from the Caspian Sea. The
largest individual observed by Nordquist in the Baltic was 3-15 mm. long.
Sars regards it as a true Arctic form of marine origin and "its' occurrence in the
Baltic and in the Caspian sea must be explained by a direct connection in former
times of these basins with the Glacial sea."3

There is a slight difference apparent between the figures of the falciform
process at the end of the outer ramus of the right fifth foot of the male, given
by Sars for L. grimaldii (1897 op. cit.) and for L. macrurus in his Crustacea of
Norway, vol. IV Copepoda-Calanoida, Part VII and VIII, pi. 55, Bergen 1902.
According to these figures the process is broader and shorter in grimaldii than
in macrurus. The examples of grimaldii from Alaska agree in this respect with
macrurus. There is a prominent ental cone on the first basal joint of the left
p 5 tf, corresponding with fair approximation to that indicated in the figure by
Sars, 1897, op. cit., pi. 4, f. 18.

9. Eurytemora gracilis (Sars).

Temorella gracilis Sars (Jana Expedition, op. cit., 1898, p. 336).

This species was originally taken in the lower part of the river Jana, in the
same locality as Limnocalanus grimaldii. A single damaged female, referred
tentatively to E. gracilis, occurred in the gathering from station 21 d, e, f, lat.
68° 41' N., 165° 10' W., temperature 45-5° F., August 16, 1913, surface. The

1 Oscar Nordquist: Die Calaniden Finlands. Bidrag till Kannedom af Finlands Natur och Folk,
vol. 47, pp. 191-275, 10 pis. Helsingfors 1888.

2 G. O. Sars. Pelagic Entomostraca of the Caspian Sea. Annuaire du Musee Zool. de 1'Acad. Imp.
des Sciences de St. Petersbourg 1897, pp. 38 to 49 of the reprint which I owe to the courtesy of the author.

3 G. O. Sars: The Cladocera, Copepoda and Ostracoda of the Jana Expedition. Annuaire Mus.
Zool. St. Petersbourg, III, 1898, p. 335.

12 K

Canadian Arctic Expedition, 1918-18

terminal set« of the natatory legs in the original description are cultriform,
dilated in the middle. Owing to the state of preservation of the specimen at
my disposal, I can say nothing on this point.

The length was 1-52 mm., the anterior antennae were broken. Relative
lengths of anal .segment and caudal furca: anal segment 9, furcal length 15,

Fig. 3. Eurytemora gracilis 9 . Urosome from above.
Fig. 4. Same. Part of fifth leg.

width of caudal ramus 2; surface of caudal rami smooth (Fig. 3). In the last
pair of legs (p. 5), the distal joint was lost; the unguiform process of the proximal
joint of the Ramus (Re 1) projects nearly, horizontally inwards, abruptly
narrowing to a distal acuminate portion which is ciliated on the inner edge
(Fig. 4). Genital segment with lateral convexities separated by a constriction
(Fig. 3).

10. Eurytemora herdinani I. C. Thompson and A. Scott, 1898.

This is one of the most typical and abundant Copepods of the gulf of St.
Lawrence. It was first obtained in 1897 by Prof. W. A. Herdman, who collected
surface plankton through the ship's pump continuously day and night whilst
the steamer was going at full speed across the Atlantic. Though not previously
observed on the Pacific coast, it was taken at a number of stations by the Can-
adian Arctic Expedition: Tables I, II, VI, VII, IX, station 42p (under
Pseudocalanus) , and the following.

Station 17 a,b,c: 60° 9' N., 167° 38' W., three surface hauls, with net number
3, fifteen minutes each, preserved in one vial, July 6, 1913. Numerous small
copepods, mostly adult <? , some young forms, but not one female.

TABLE XI (STA. 17o, 6, c.)

Eurytemora herdmani cT 45

Acartia d" 45

Tortanus discaudatus <? 10

100

Probably both Acartia longiremis and A. clausi are present in subequal
numbers, but as the metathoracic thorns of longiremis may be lost or worn down,
it is not safe to differentiate these species by male characters. Another vial
of the same date, labelled Sta. 17e, surface 30 minutes, same locality and net,
contained a scanty gathering which included some Euphausiid eggs, one male
Eurytemora herdmani, and a number of Acartia longiremis, both male and female.
To begin to understand these relations it would be necessary to know approxi-
mately the time of day and the light conditions. In any case the assembling
of males, as displayed in the table above, is not too commonly observed.
Station 19: See under Acartia longiremis.

Marine Copepoda 13 K

Station 36: Off cape Lyon, Darnley bay, Northwest Territories, five minutes
tow in surface, with net number 4,1 from ship, water depth five fathoms , August
23, 1914. Only eight copepods preserved, all males: five Acartia longiremis
and three Eurytemora herdmani. One of the latter was 1-20 mm. long; a male
from station 21 (Table II) measured 1-36 mm.

Station 410: Bernard harbour (outer harbour), surface net number 3,
five minutes, August 1, 1915. One female in company with Cyclopina schneideri,
Harpacticus uniremis and Harpacticus super flexus.

11. Eurytemora johanseni, n. sp.

This species was taken in company with E. herdmani (Table II and Table
XII) from which it may be recognized externally by the length of the caudal
furca. Whereas E. herdmani is longifurcate, the furca much exceeding the
length of the anal segment, E. johanseni is brevifurcate, the furca and anal
segment being subequal in length (Fig. 5).

I 1

Fig. 5. Eurytemora johanseni 9 .
Dorsal view of hind-body.

Description of female: total length 1-28 mm., anterior antennae as long
as forebody; length of caudal furca 0-112 mm., of anal segment 0-104 mm.,
wings of genital segment small; mouth-parts as in E. velox. The fifth legs (p. 59)
are four-jointed as in the type species; the unguiform process of the penultimate
joint (Re 1), not exceeding Re 2 in length, is coarsely denticulated on its outer
side; the right Re 2 (distal joint of the appendage) is larger than the left and
crenulated on its inner border (Fig. 6).

Fig. 6. Same. Fifth legs.

Description of the male: total length 1-12 mm. The anterior antennae
are to be distinguished from those of E. herdmani on close inspection (Figs. 7-10).
In both species, the intumescence in the middle section of the right antenna
is formed by joints 13-18 inclusive. Of the two distal joints beyond the bend,
the penultimate joint is to the terminal joint as 5: 8 in herdmani and as 4: 5 in
johanseni. In other words, the penultimate joint of the right antenna of E.

1 Net as net No. 3 (see note p. 4K), but made of fine silk.

14 K

Canadian Arctic Expedition, 1913-18

johanseni is subequal to that of E. herdmani, but the terminal joint is shorter
than in herdmani. Again, in E. herdmani, joint 12 carries a long curved ungui-
form spine commonly applied to the face of the antenna, though capable of
being extended forwards. In E. johanseni, joint 12 carries a spine standing out
at right angles to the face of the antenna, less than half the length of that of

Figs. 7-10. Details of right antenna of male.

7. E. johanseni, distal joints.

8. E. herdmani, same.

9. E. johanseni, spine on joint 12.
10. E. herdmani, same.

herdmani, slightly curved and minutely bifid or flaring at the tip. Other spines
occur on the proximal joints but only the spine on joint 12'Jias specific Rvalue.
In both species the right antenna presents a proximal as well as a distal swelling
with short narrow joints intervening.

Fig. 11. E. johanseni 6 . Left p. 5 B2
Fig. 12. Same. Fifth legs from behind.

Fifth legs (p 5 d1): the left B2 shows a strong ental protuberance (Fig. 11);
the inner margin of the right B2 is entire; the terminal joint of the left foot
with subdistal spoonshaped expansion (Fig. 12). In E. herdmani there is a
prominent cylindrical ental tubercle at the proximal end of the right B2.

Marine Copepoda 15 K

In one specimen the caudal furca was asymmetrical, suggesting a mingling
of characters, as shown in Fig. 13.

The arrangement of the setae on the natatory legs agrees with that of E.
velox. except that the third joint of the outer branch of the first foot (p. 1 Re 3)

Fig. 13. E. johanseni $ .
Abnormal caudal furca.

is furnished, as in E. herdmani, with seven setae (2 se, 1 st, 4 si); in E. velox
this joint has six setae (1 se, 1 st, 4 si).

12. Metridia longa (Lubbock, 1854).

Station 27r. Collinson Point, Alaska, October 2, 1913 : one male, with the
left anterior antenna geniculate; length 3-88 mm.

Station 290. 70° 20' N., 140° 30' W., depth 150 fathoms: several vertical
hauls with net number 5, from 0 to 150 fathoms, April 6, 1914. The gathering,
amongst others (see under Calanus finmarchicus) , contained females and young ;
one female was 4-88 mm. in length.

Station 42y. See Table X. Young individuals.

Station 42z. See under Pseudocalanus. A young Metridia longa of 1-67
mm. was taken.

From these scanty records it is evident that this representative Arctic
species was only present in traces. Its abundance at suitable places in the north
is shown in the following extract, which I have not seen quoted before,
from A. E. Nordenskiold : The Voyage of the Vega round Asia and Europe,
translated by A. Leslie, London (Macmillan) 1881, vol. II, pp. 54-56: "The
common idea that all animal life ceases when the interior animal heat sinks
under the freezing point of water, is not quite correct. This is proved by the
remarkable observation made . . . during the wintering at Mussel Bay in
1872-73, that small Crustacea can live by millions in water-drenched snow at
a temperature of from — 2° to — 10° -2 C. If during winter one walks along the
beach on the snow which at ebb is dry, but at flood tide is more or less drenched
through by sea-water, there rises at every step one takes, an exceedingly intense,
beautiful, bluish-white flash of light, which in the spectroscope gives a one-
coloured labrador-blue spectrum. It produces indeed a peculiar impression on
a dark and stormy winter day (the temperature of the air was sometimes in
the neighbourhood of the freezing-point of mercury) to walk along in this
mixture of snow and flame. On a closer examination, it appeared that this
light-phenomenon proceeded from a minute crustacean, which, according to
the determination of Prof. W. Lilljeborg, belongs to the species Metridia armata
A. Boeck (= M. longa). When the temperature [of the snow-sludge] sinks
below — 10° C., the power of this small animal to emit light appears to cease."

16 K Canadian Arctic Expedition, 1913-18

13. Metridia lucens Boeck, 1864.

I have only one record of this species in the collection: one male, 2 mm.
Inni;, at station 130, h, 54° 30' N., 159° 42' W., July 1, 1913, at the surface. It
has been reported very common, summer and winter, in the San Diego region.1

14. Paralabidocera amphitrites McMurrich, 1916.

Station 14. 54° 23' N., 164° 45' W., surface, 15 minutes, net number 3.
July 2, 1913. Two males in company with an ovigerous Harpacticus uniremis.

Station 18. Table I; many young, but no adults, were taken here, and
again at station 19 (see under Acartia longiremis).

Station 21a, 6, c. Table II, young and adults of both sexes.

Station 21d, e, f. 68° 48' N., 165° 10' W., net number 3, three surface
hauls of 15 minutes each, temperature 45-5° F., August 16, 1913.

TABLE XII (STA. 2ld, e,f).

Centropages mcmurrichi 9 1

Eurytemora gracilis 9 1

Eurytemora herdmani d" 4

Eurytemora herdmani 9 3

Eurytemora johanseni d1 36

Eurytemora johanseni 9 6

Eurytemora johanseni 9 stage V 4

Paralabidocera amphitrites 9 4

Paralabidocera amphitrites 9 stage V 14

Paralabidocera amphitrites 9 stage IV 3

Paralabidocera amphitrites d* 5

Paralabidocera amphitrites d" stage V 6

Paralabidocera amphitrites stage III 4

Acartia (clausi-longiremis) d" 9

100

Professor McMurrich's material consisted of two females and one male,
collected by himself in September, 1912, from a patch of "brown water," about
3J miles off Amphitrite point, Vancouver island.2 They were sub-mature
specimens, not having achieved the final ecdysis, and whilst they exhibited
certain generic features, the specific characters were in part lacking. The missing
characters relate chiefly to the right anterior antenna of the male, the fifth pair
of legs of the male, and to the genital segment of both sexes. In the male, the
fifth feet undergo a remarkable transformation on the passage to maturity.

The lateral cephalic hooks and the rostral processes are like those of Pontella
and some species of Labidocera. Paralabidocera further agrees with the definition
of Labidocera in the absence of a rostral lens, in having the dorsal eyes contiguous
in the male, and in having less than seven teeth on the mandible. It differs
from Labidocera and agrees with Pontella in having 24 joints in the anterior
antennae of the female, seven joints in the second maxilliped, and three joints in
the inner branch of the first feet. The abdomen is three-jointed in the female,
five-jointed in the adult male. The last segment of the thorax is distinct in the
female, but in the male its median part is suppressed in dorsal view, only the
lateral lobes having a joint-line, as in Labidocera kroyeri & Giesbrecht.

1C. O. Esterly: The Pelagic Copepoda of the San Diego Region. Univ. of California Publications,
Zoology, Vol. 2, No. 4, October 14, 1905, p. 177.

2J. P. McMurrich: op. cit. 1916, pp. 82-87, f. 8-14.

Marine Copepoda

17K

Length of female 3 • 6 mm., of male 3 • 09 mm. The rostral processes are long
and acute in both sexes, in the young as well as in the adult (Fig. 14). Some-
times, as seen specially in the male, the left rostral hook is smaller than the right.

Fig. 14. Paralabidocera.
Front with right eye and rostral hooks of female.

The lateral lobes of the last thoracic segment are symmetrical in the female;
they are broadly rounded, with a small protuberance at the middle of the lateral
border, or this may be worn down so that the lateral lobe appears evenly rounded
(Fig. 15).

Fig. 15. Paralabidocera.
Hind-body of female from above; sp. Spermatophore.

In the male, the lateral lobes are very unequal, that on the left side resem-
bling the female, though less broadly rounded in side view, sometimes triangular

Fig. 16. Paralabidocera. Hind-body of the male from above.
Fig. 17. Paralabidocera. Urosome of female in side view.

and pointed. The right lateral lobe is drawn out into a long spike nearly or
quite reaching to the end of the second segment of the urosome (Fig. 16).
69085—2

18 K

Canadian Arctic Expedition, 1913-18

The genital segment of the male (Fig. 16) exhibits a small lobe and notch
on the left side. The genital segment of the female (Fig. 15) carries a largo
wing-like lobe on the left side, terminating in a recurved hook; this hook is easily
lost, so that the lobe then appears to end bluntly. In side view the segment
presents a ventral convexity and two small curved hooks, right and left of the
genital opening (Fig. 17).

The anterior antennae of the female reach to the end of the forebody. Of
the 24 segments of which they are composed, numbers 3 to 8 are short and
subequal; the antenna breaks readily between the 8th and 9th joints. The
right grasping antenna of the male, with the geniculation between the 18th and
19th joints, is more like that of Pontella than that of Ldbidocera (Fig. 18).

Fig. 18. Paralabidocera.
Terminal portion of right antenna of male.

There is a serrated upraised flange upon joint 17, a serrated border upon joint
18, and two toothed edges upon the compound joint 19-21, namely, a long
proximal and a short distal comb. The terminal part of the appendage, beyond
the bend, consists of three distinct segments, corresponding respectively to
joints 19-21, 22-23 and 24-25. This is a generic character, inasmuch as the
right anterior antenna of the male Labidocera has four terminal segments, hat
of Pontella two.

In the second or posterior antennae, B2 is fused with Hi 1, the zone of fusion
being indicated by a shallow impression at the level of the insertion of a group
of two si; measuring Ri from this point, the two rami are subequal in length.

Fig. 19. Paralabidocera. Second maxilliped.

In the seven-jointed second maxilliped (Fig. 19), the inner margin of B2
is denticulated as in Labidocera; distally this joint carries two long setae and

Marine Copepoda

19 K

one additional shorter seta; Ri 1 has two setae, Ri 2 has one, Ri 3 has one, Ri
4 has one, and Ri 5 has three apical setae. The distal lobe of Bl has one long
seta and two very small anterior setae at its base, one of which was distinctly
plumose. In the example figured, one of the two setae of the middle lobe of
Bl is lost, its place being indicated by a small mamelon.

The distribution of the setae on the swimming legs agrees with Labidocera,
the external setae being set in deep notches. In the fifth legs of the female
(Fig. 20), it is to be noted that the right and left Bl are confluent across the
middle line; B2 has two setse on its hinder surface, one of which is minute.

Fig. 20. Paralabidocera.
Fifth legs of female from behind.

In the adult male the right foot ends in a rounded chela (Figs. 21 and 22);
in one case it was observed that the chela was firmly grasping thejight anterior

Fig. 21. Paralabidocera. Fifth feet of male.

Fig. 22. Paralabidocera. Chela of right leg.

Fig. 23. Paralabidocera. Left B2.

Fig. 24. Paralabidocera. Left end- joint.

antenna of the same individual, which it had presumably caught hold of in
he death-struggle. A lobe on the left B2 (Fig. 21) is directed towards a cor-
69085—21

20 K Canadian Arctic Expedition, 1913-18

responding tuberosity on the right Bl; when the left B2 is disarticulated and
viewed from the side, the lobe appears as the proximal end of an elevated border
(Fig. 23). On the anterior surface of the terminal joint of the left foot there
is an elongate depression beset with groups of very fine hairs, with a small se
beside it (Fig. 24).

The mandible has five teeth followed by a group of small setae; the first
(ventral) tooth is large. The rostral eye has no lens.

15. Acartia clausi Giesbrecht.

Station 17 (Table XI), station 18 (Table I), station 20a (Table IX), station

21 (Table II), station 25 (Table III). Station 20h: Port Clarence bay, Alaska,
water depth three fathoms, net number 3, surface-tow five minutes, amongst
seaweed, August 4, 1913. A small vial contained a number of Cladocera (Podon
leuckarti and Evadne nordmanni), a young Caprella, and several Acartia clausi,
male and female. The arrangement of the setae on the swimming legs agrees
with the description given by Giesbrecht, and the first basal joint (Bl) of the
second to the fourth feet has an emarginate outer border and an incised inner
border as in the type.

Station 25, off Cooper Island, near Point Barrow, is the only station within
the Arctic Circle where this species was taken, although station 21 lies north
of Bering strait. Port Clarence lies to the south of the strait, about 65C
north latitude. Sars (1903) has never met with A. clausi in any samples of
plankton from the Arctic Ocean. On the south and west coasts of Norway
it is as common as A. longiremis with which it is often found.

This species is more of an estuarine and inshore form than is A. longiremis.

16. Acartia longiremis (Lilljeborg, 1853).

This is an Arctic species with a wide southern extension.

Station 6b. 56° 26'N., 133° OO'W., just below the surface, 15 minutes, net
No. 4, June 24, 1913. This was a thin Acartia plankton, numbers of A. longire-
mis being noted and, in addition, two male Cumaceans and several Ostracods.

Station 126, c. 54° 38'N., 157° 45'W., two surface tows of five minutes
each, net number 3, June 30, 1913. A few A. longiremis <? and 9 were taken,
together with a trace of Oithona and a number of young Amphipoda-Hyperidea.

Station 13 a, b, c. 54° 30'N., 159° 42'W., three surface tows of five minutes
each, net number 3, July 1, 1913. The catch was very scanty but there was a
male longiremis, 1-12 mm. in length; the number of setse on the inner border
of the two-jointed inner branch of the fourth foot (p. 4 Ri Si) is 3, 5, the same
as in A. clausi; Sars figures 2, 5.

Station 17 a, b, c. Table XI. Whereas most Calanoids are largely dif-
ferentiated by male characters, Acartia is an exception, and the males of A.
clausi and longiremis are hard to distinguish, if the thorns are lost from the
last thoracic segment.

Station 18: See under Calanus finmarchicus and remarks on table I.

Station 19 a-e. 63° 43'N., 165° 24'W., surface, July 8, 1913, net number

3, five tows of fifteen minutes each. Nearly fifty Acartia identified in part
as longiremis, about half as many young Paralabidocera, and a single male
Eurytemora herdmani.

Station 21 a, b, c, and d, e, f. Tables II and XII.

Station 25 b, c. Table III.

Station 36. Off cape Lyon, Darnley bay, Northwest Territories, net number

4, surface tow of five minutes, August 23, 1914. Five males in company with
Eurytemora herdmani (q. v.). Phytoplankton was represented by Ceratium,
Chaetoceras and Coscinodiscus.

Marine Copepoda

21 K

Station 4O. Bernard harbour (outer harbour), Northwest Territories,
water depth 10 fathoms, three vertical hauls 0 to 5 fathoms through hole in
ice, net number 3, temperature -0-8°C., July 1, 1915. Coscinodiscus and
Balanus nauplii were abundant. The copepods present were: Acartia lon-
giremis 9 , Oithona similis 9 , Ectinosoma neglectum and Idycea furcata 9 .

Station 42y. Table X.

Station 42z. See under Pseudocalanus.

Station 43e. Table VII. A female carried two spermatophores.

17. Acartia tumida, n. sp.

Three examples of a third species of Acartia were taken in surface, at
stations 13 a, 6, c, in company with Calanus tonsus (q. v.) and Acartia longiremis
(q. v.). The position was 54° 30' N., 159° 42' W., July 1, 1913, net number 3.

Length of female, 2-00 mm.; anterior antennae not exceeding length of
forebody, reaching as far as the front part of the genital segment when laid
back, having about the same relative length as in A. bifilosa. Rostral filaments
are present, widely separated in ventral view; labrum large trilobate with
ciliate edges, as figured by Sars for A. longiremis. Lateral borders of last
thoracic segment smooth (Fig. 25); urosome smooth, some minute points
dorsally near the posterior edge of the genital segment and at posterior edge
of the pre-anal segment; anterior antennae without thorns.

The caudal setae (Fig. 26) were broken, some of their swollen basal parts
remaining attached to the short and broad rami.

Fig. 25. Acartia tumida: end of thorax and the urosome in side view.
Fig. 26. Same. Urosome from below.

In the swimming feet, the terminal seta (st) of the outer ramus is much
longer than Re 3, longer in fact than the whole Re, with a strongly serrated
outer edge; the arrangement of the setae is the same as in A. clausi.

Fig. 27.

Acartia tumida. Fifth legs of female, shown complete on one
side, the basal joints parallel.

Fifth legs (p 5 9): the basal joints, right and left, are parallel; the terminal
joint, representing the Re, has a swollen proximal portion followed by a narrow

22 K Canadian Arctic Expedition, 1913-18

neck, upon the distal part of which there commence two rows of small denticu-
lations pointing distally. These denticulations are evenly disposed, increasing
slightly and then diminishing in size, to be continued upon the proximal half
of the attenuating setiform process (Fig. 27). This delicate and regular serru-
lation is quite different from the coarse denticulation figured for Acartia tonsa,
where the teeth are few in number, the proximal largest.

18. Tortanus discaudatus (I. C. Thompson and A. Scott, 1898).

In Professor Herdman's traverses of the Atlantic, which have been referred
to under Eurytemora herdmani, he obtained another leading component of the
Gulf of St. Lawrence copepod plankton, namely, the present species. Whilst
in America he paid a visit to Puget Sound, where he carried out some dredging
and tow-netting. Amongst the more abundant forms in the Puget Sound
gatherings was this same species, new for the Atlantic and new for the Pacific.1
It composes 50-75 per cent of the summer copepod plankton off Souris, Prince
Edward Island, and is very abundant off the Biological Station at St. Andrews,
N.B.

Station 17 a, 6, c. See Table XI.

Station 18. See Table I.

Station 20a. See Table IX.

B. CYCLOPOIDA, ETC.
19. Oithona similis Glaus, 1866.

This small and slender species is apt to escape through the meshes of
ordinary tow-nets, but none the less it appears frequently in Mr. Johansen's
gatherings. Like Acartia longiremis, it is an Arctic form with a southern ex-
tension.

Station 12 b, c. See under Acartia longiremis.

Station 12 d. Same position, surface, 15 minutes, net number 4, June 30,
1913. Phytoplankton (Coscinodiscus, Peridinium, Rhizosolenia, chain algae),
Tintirnoids and Oithona.

Station 21 a, 6, c. Table II.

Station 25 6, c. Table III.

Station 27y 2. Table V.

Station 29gr 4. See under Euchaeta norvegica.

Station 30 a. Table VIII.

Station 40 c. Bernard harbour, Dolphin and Union strait, water depth 9
fathoms, three vertical hauls, 0 to 3 fathoms, through hole in ice; net number 3,
June 7, 1915.

TABLE XIII (STA. 40c).

Pseudocalanus elongatus, immature 9 .
Oithona similistf.
Cyclopina schneideri.
Harpacticus superflexus d" .
Dactylopusia signata 9 .

Station 40 d. Same locality, depth, and net, six vertical hauls through hole
in ice, 0 to 5 fathoms, June 8, 1915.

1 W. A. Herdman, I. C. Thompson, Andrew Scott: On the plankton collected continuously during
two traverses of the North Atlantic in the summer of 1897; with descriptions of new species of Copepoda;
and an Appendix on dredging in Puget Sound. Trans. Liverpool Biol. Soc. XII, pp. 33-90, pis. V-VIII,
Liverpool 1898.

Marine Copepoda 23 K

TABLE XIV (STA. 40d).

Pseudocalanus elongatus 9 .
Pseudocalanus elongatus <? stage V.
Eurytemora herdmani 9 (1-4 mm.) .
Oithona similis.
Cyclopina schneideri.
Ectinosoma neglectum.
Harpacticus super flexus d" (1-05 mm.)-
Dactylopusia signata.

Station 40e. Same locality, depth, and net, three vertical hauls, 5-0
fathoms, June 10, 1915. Several Oithona similis with Dactylopusia and Ectino-
soma neglectum.

Station 40r. See under Acartia longiremis. A female Oithona measured
0-86 mm., a male 0-78 mm. The relative lengths of the last thoracic segment,
the abdominal segments and the furca were : —

Th5. Abl. Ab2. Ab3. Ab4. Ab5. Furca.

Male 7 10 8 7 7 7 7

Female 8 19 9897

Station 41s. See Table VI.

Station 42p. See under Pseudocalanus.

Station 42y. Table X.

Station 43e. Table VII.

Station 466. Bernard harbour, depth 6 fathoms, ice 5 feet thick, vertical
haul with net number 3, from bottom to surface, temperature 29-2° F., Febru-
ary 5, 1916. About half a dozen Copepods in all, including: Oithona similis,
Oncaea conifera, Idycea furcata, and Dactylopusia signata.

Station 46/i. Dolphin and Union strait, off Chantry island, depth about
50 feet, ice 4 feet thick, three vertical hauls, with net number 3, from 33 feet
to surface, June 10, 1916. Several Oithona, with several immature Idycea furcata
and one Cyclopina schneideri 9 .

20. Cyclopina schneideri T. Scott, 1903.

Thomas Scott: Notes on some Copepoda from the Arctic Seas collected in 1890 by the
Rev. Canon A. M. Norman, F.R.S., Ann. Nat. Hist. (7) XI, 1903, p. 6.

Station 40c. See Table XIII.
Station 40d. Table XIV.

Station 410. Bernard harbour (outer harbour), depth 0-2 fathoms, surface
5 minutes, net number 3, August 1, 1915.

TABLE XV (STA. 410).

Eurytemora herdmani, one female.
Cyclopina schneideri, one male, one female.
Harpacticus uniremis, one (injured) .

Harpacticus super flexus, 48 examples, including several males and one female with
ovisac.

Station 46h. See under Oithona. A female from this station measured
0-84 mm., caudal rami shorter than anal segment as 5:6; length of caudal
ramus to breadth as 5: 3; interrelations of caudal setae as in C. litoralis Brady.1
Anterior antennae 12-jointed, with six terminal subequal small joints; of the
proximal joints the fourth is the shortest, the sixth the longest, agreeing with
Scott's figures and thus establishing the constancy of these proportions. The
mandible, also figured by Scott, has a large B2 (the basal joint of the palp),
shaped like an ascidian, carrying at the summit an outwardly curved two-jointed
Ri, which is separated by a wide concave interval from the four-jointed Re.

1 W. Giesbrecht: Die litoralen Cyclopiden des Golfes von Neapel. Mitth. zool. Stat. Neapel 14,
1901 ,pp. 4(M6.

24 K Canadian Arctic Expedition, 1913-18

The fifth legs (Fig. 28) are two-jointed, the second joint carrying three
setae at the end, a slender one in the middle, a stout vaned (bilimbate) se and a
similar but smaller si; the proximal joint carries a simple se, like the apical seta.

Fig. 28. Cyclopina schneideri.
Fifth leg of female.

The male, from station 410, was nearly 0-74 mm. long. Anterior antennas
two-thirds the length of the forebody, with 16 joints; joints 4 to 9 inclusive are
telescoped, 10 to 14 inclusive form the intumescence; the 10th joint carries two
spiniform processes applied to the anterior face of the llth; the remaining
segments of the enlarged part with pectiniform setae.

21. Oncaea conifera Giesbrecht, 1891.

For reference see Nordisches Plankton, Bd. IV, Lief. VIII, Copepoden by Dr. van Breemen,
p. 188-9, Kiel und Leipzig, 1908.

Station 30a. See Table VIII.

Station 42y. Table X.

Station 42z. See under Pseudocalanus. A single female preserved from this
station measured 0-65 mm. in length.

Station 466. See under Oithona. This is an Arctic species with an exceed-
ingly wide southerly range even reaching to the Antarctic ocean. Or it might
perhaps be described as a Mediterranean species, ranging north, south, east and
west from its centre of distribution. It cannot be stated positively whether
it is an Arctic emigrant to the south or a Mediterranean migrant to the north.
The evidence from the present collection bearing upon this point is not very
cogent, but, so far as it goes, it points to the north as the home of this species.
What is true of the distribution of Oncaea conifera applies also to Oithona similis,
except that the latter, like Acartia longiremis, penetrates into the Baltic, from
which sea Onccea conifera appears to be excluded.

C. HARPACTICOIDA.

22. Ectinosoma neglectum Sars, 1904.
G. O. Sars: Crustacea of Norway. Copepoda-Harpacticoida, Bergen, 1904, p. 31.

Station 40d. See Table XIV.

Station 4Qe. See under Oithona.

Station 40r. See under Acartia longiremis.

An immature female from station 40r was 1-07 mm. long; the distal
joints of the fifth legs were not separated from the rest of the lamelliform ap-
pendage, but the marginal setae were present and elongated. The inner and

Marine Copepoda

25 K

outer branches of the fourth legs were 3-jointed and equal. "Anterior antenna?
with five joints; in the figure of the antenna most of the setae are omitted; on
the terminal joint one of the seise has a -swollen base (Fig.*29).

Fig. 29. Ectinosoma neglectum 9 juv.
Front and anterior antenna.

The anterior lip (labrum) projects in front of the mouth-parts as an acute
recurved hook in both sexes. Two males, from station 40e, measured 0-77 and
0-86 mm. respectively. On the ventral side, the posterior borders of the ab-
dominal segments are fringed with delicate spinules, including the pre-anal and
anal segments, on which the spinules are smaller. On the dorsal aspect, the
posterior borders of Ab 1, Ab 2, Ab 3, and Ab 4 are conspicuously fringed.
The urosome of the male consists of six segments: Th 5 and Ab 1-5.

The anterior antenna? of the male (Fig. 30) are thick and short, with a
double protuberance at the back of the third joint. This protuberance is shown
as a single tubercle in the figure by Sars.

Fig. 30. Ectinosoma neglectum.
Anterior antenna of male, from below.

The posterior antennae resemble those of E. sarsi; the Re is 3-jointed with
the following relative lengths of the joints: 6, 4, 11; Re 1 carries a distal seta,
Re 2 a stronger and longer seta, Re 3 a short setula and two terminal plumose
setae, one longer than the other. The mandibular palp likewise resembles that
of E. sarsi: a long B2, with a distal group of three setae, carries a terminal
one-jointed Re and, at a distance from the latter, a shorter tri-setose Ri.

26 K

Canadian Arctic Expedition, 1913-18

The caudal furca is as long as the anal segment (Fig. 31): there is a short
strong spine on the outer margin of each ramus and, more distally, a group
of two slender auxiliary setae.

Fig. 31. Ectinosoma neglectum d".
Left ramus of caudal furca from above.

Fifth feet (p. 5 c?) have the marginal spines not exactly with the same
interrelative lengths as figured for the type by Sars, but the anterior or appen-
dicular seta arises from the distal joint near the base as in the original (Fig. 32).

OJLl

Fig. 32. Ectinosoma neglectum.
Fifth feet with part of urosome.

Swimming feet (pl-p4) show some variation in arrangement of setae in
different individuals and even on the two sides of one. All the Ri 3 have five
setae (1 se 4 si); pi Re 3 has six setae, as in E. sarsi (3 se, 1 st, 2 si); p 2 Re
3 has seven setae (3 se, 1 st, 3 si) instead of eight in E. sarsi; p 3 Re 3 has eight
setae (3 se, 1 st, 4 si) ; in two specimens the proximal se of p 3 Re 3 was absent
on one side, in another the full number occurred on both sides; p 4 Re 3 has
seven setae (2 se, 1 st, 4 si).

23. Ectinosoma finmarchicum (T. Scott, 1903.)

Station 27 t, u. See Table IV.

Female of 1-07 mm., carrying a yellow ovisac in the preserved state. An-
terior antennae 6-jointed; p 2 Re 3 with seven setae as in E. neglectum. Upper
lip bluntly rounded. The fifth legs have the inner seta of the lamellar process
and the middle seta of the distal lobe equal and longer than the rest (Fig. 33).
The appendicular seta arises from the distal lobe near the base, whereas in

Marine Copepoda 27 K

Scott's figure (op. cit. pi. 1, f. 13), it is shown arising from the basal joint. The
inner lamellar process and the distal lobe of p 5 are elongate and subequal.
The caudal setae reached a length of 0 • 64 mm.

Fig. 33. Ectinosoma finmarchicum.
Fifth foot of female.

Sars cites • E. finmarchicum as a doubtful synonym of E. elongatum, adding
that the latter is of smaller size, 0-88 mm. He figures the appendicular seta of
the distal lobe of p 5 in E. elongatum as arising not far from the distal margin
of the lobe.

24. Pseudobradya minor (T. and A. Scott, 1896).

Station 4ln. Bernard harbour (inner harbour), depth 0-2 fathoms,
surface 5 minutes, net number 3, August 9, 1915. Associated with Harpacticus
super flexus (see below).

Length of female 0-664 mm., caudal setae 0-178 mm. Anal segment and
caudal ramus form a simple cone in side view, the ramus appearing slightly

Fig. 34. Pseudobradya minor.
Anterior antenna of female.

shorter than the anal segment as 5: 6. Anterior antennae (Fig. 34) 6-jointed,
proximal parts expanded. Posterior antennae with 3-jointed Re, the pro-
portional lengths of the joints being 2, 1, 9.

First and second maxillipeds are shown in their relative positions in Fig. 35.
The first maxilliped (mp 1) is stout and curved, the two proximal joints subequal

28 K

Canadian Arctic Expedition, 1913-18

in length. The second maxilliped (mp 2) is short and straight, with very long
plumose basal seta, about twice the length of the appendage.

Fig. 35. Pseudobradya minor.
First and second maxillipeds.

The arrangement of setae on the thoracic legs is the same as that indicated
for the two before-named species of Ectinosoma; in particular p 2 Re 3 has
seven setae (Fig. 36).

Fig. 36. Pseudobradya minor. P 2 Re 3.
The outer margin is below.

In the third foot (p 3) the basal joints (Bl and B2) are broad, and the
rami are inserted upon the outer half of B2, so that the right and left Ri are

Fig. 37. Pseudobradya minor.
Part of third foot, anterior surface.

widely separated; B2 has an se, and rows of spinules at the bases of the rami
and around the inner angle; Bl has a distal marginal anterior row of spinules
interrupted in the middle of the series (Fig. 37).

Marine Copepoda 29 K

The fifth foot resembles that of the type, but the marginal seta are uni-
formly longer than in the figure by Sars (Fig. 38).

33.

Fig. 38. Pseudobradya minor.
Fifth foot of female.

The form here described differs slightly from the typical Ps. minor in
certain proportions, somewhat as Ectinosoma neglectum differs from E. sarsi.
In the gathering from station 27 t, u, (see remarks under Table IV) there was
another Pseudobradya, of 0-86 mm., caudal setae 0-51 mm., which may be
the Ps. acuta of Sars. It comes very near to Ps. acuta by its rostrum, p 5, and
furca; but in p 5 the appendicular seta arises near the base of the distal joint,
whereas in acuta Sars describes and figures it as issuing from the basal joint.

In Ps. minor Sars mentions the caudal setae "not much elongated". In
Ps. acuta the caudal setae are "slender and elongated". Sars obtained only
two examples of Ps. acuta, in company with Ps. minor, at Selven, Trondhjem
Fiord. A similar origin of the appendicular seta from the basal joint was
figured by T. Scott for Ectinosoma finmarchicum, wherein this species would
differ from E. elongatum Sars, which was also found only at Selven in 3-6 fathoms,
on muddy sand. The value of the appendicular seta as a diagnostic feature
seems not to be fully established.

25. Harpacticus superflexus, n. sp.

This species resembles H. flexus Brady in all but size and the shape of the
finger of the posterior maxilliped.

Station 256, c. See Table III. Immature.
Station 30a. Table VIII. Immature <?.
Station 40c. Table XIII <?
Station 40d. Table XIV. rf1 1 -05 mm.
Station 410. Table XV. 48 examples.
Station 41n. See under Pseudobradya.

Length of female, 1-20 to 1-26 mm., of male, 1-04 to 1-12 mm.; caudal
furca a little longer than anal segment, caudal setae, 0-65 to 0-69 mm., some-
times shorter in the male. Urosome stout, barrel-shaped; caudal rami parallel,
as broad as long, spinose distally. The body in the preserved state is often
transparent. The cephalosome has a polished convex dorsal surface; the
remaining segments of the thorax are smooth, with a metallic lustre, and groups
of small dark spots on the pleurae.

30 K

Canadian Arctic Expedition, 1913-18

Anterior antennae 9-jointed, seven-tenths the length of the cephalosome
measured in the middle line. Posterior antennae with Re two-jointed (Fig. 39);
the number and arrangement of setae is subject to variation, as is the relative
length of the two joints.

Fig. 39. Harpacticus super flexus.
Base of posterior antenna showing the two-jointed Re.

The mandible has the structure shown in Fig. 40, both rami of the palp
being one-jointed; the outer ramus is the smaller; on the other mandible of
this individual instead of the two si of Ri shown in the figure, there was a group
of three setae as in Tigriopus (Sars).

Fig. 40. Harpacticus superflexus. Mandible.

The maxilla was like that of H. chelifer, with two long plumose setae behind
the masticatory claws on B 1, as figured by Sars; below the claws (observed
in the male) were two subequal setae with distended proximal portions and
long-plumed attenuated distal portions; B2 bifid, the proximal inner smaller
lobe carrying two equal plumose setae, the upper larger lobe, a group of setae;
Ri and Re both tri-setose.

First maxilliped (mp 1): B 1 with three setigerous digitiform inner lobes
(Li); B 2 is the distal digitiform segment of the appendage, carrying a sub-

Fig. 41. Harpacticus

us. Terminal portion of first maxilliped.

distal group of four setae and terminating in the claw or dactylus of the appen-
dage; above the claw, and parallel with it, there is a plumose seta, and another
smaller seta below it (Fig. 41).

Marine Copepoda

31 K

Second maxilliped (mp 2): like that of H. flexus, with simple fusiform
hand, but the dactylus is shorter than the hand as 2: 3 (fig. 42).

Fig. 42. Harpacticus superflexus. Second maxilliped.

The first thoracic foot (p 1) is like that of H. flexus, both rami two-jointed,
Ri about as long as the proximal joint of Re; Ri 2 with a claw-like spine and
two setae at the end, Ri 1 with distally placed si (Fig. 43) ; Re 2 ending with
three curved claws and a slender seta. In the second thoracic foot (p 2 9)
it is to be noted that the middle joint of the inner ramus (Ri 2) has two si, against
one si figured for H. chelifer} this duplication of the si was found in two successive
preparations on both sides. The third and fourth legs agree with H. chelifer.

Fig. 43. Harpacticus superflexus.
Terminal portion of inner ramus of p 1.

In the male, the second foot (p 2 d") has the mucronate process of Ri 2
only a little exceeding the length of Ri 3 (Fig. 44).

Fig. 44. Harpacticus superflexus. P 2 Ri of male.

In the third foot of the male (p 3 <?), Re 1 is two-thirds the length of Re 2
and Re 3 together, the relative lengths of these joints being 26, 19, 20; the
enlarged outer spines of Re 3 are graded as 10, 17, 27; thus Re 3 se 3 is to Re 3
as 27 : 20, the se 3 has usurped the position of the terminal seta (st), so much so
that the latter appears to belong to the series of si, of which there are four (in
addition to the st); the st has about twice the bulk of the fourth si, but it is
flexible, longer and much slenderer than the se 3. In H. chelifer <? the p3
Re 3 st is rudimentary; in H. uniremistf it makes a fourth spine. In H. gracilis <?
the st is like that of H. uniremis, but the Se 3 is the shortest of the series. The
male of H. flexus is undescribed.

32

Canadian Arctic Expedition, 1913-18

Fifth legs of female (p 5 9 ) : inner lamellar process low, broad, evenly arched,
with four marginal spines; distal joint with five marginal spines (Fig. 45).

Fig. 45. Harpacticus superflexus. Fifth legs of female.

Fifth legs of male (p 5 c? ) : inner lamellar process absent as in H. uniremis;
an arcuate row of spinules occurs on the segment (Th 5) to the outer side of
p 5; in front of this arc there is a transverse row of points, and a corresponding
oblique row occurs on the genital segment (Fig. 46).

Fig. 46. Harpacticus superflexus.
Fifth leg of male with adjacent segments.

With reference to the pelagic occurrence of this species, it may be mentioned
that Brady (Brit. Cop. 1880, II, p. 152) records that H . flexus had been taken
by the surface net in Westport Bay, Ireland; elsewhere at the bottom in depths
of 1 to 20 fathoms.

The anterior antennae of the male present the distal expansion found in
other species of Harpacticus; when viewed from the outer aspect the dactylus
is seen to possess a lateral spur and tubercle.

26. Harpacticus uniremis Kroyer.

Station 7a. 55° 42' N., 136° 20' W., surface 5 minutes, net number 3,
June 25, 1913. Seventeen examples. One female measured 1-4 mm., one male
1-28 mm., another male 0-80 mm. In addition, there were young Gammaridea
and an Ostracod (Conchoecia).

Station 13. 54° 30' N., 159° 42' W. Several surface gatherings, with net
number 3, July 1, 1913. There were some Cypris larvae of Cirripedes.

Marine Copepoda
TABLE XVI (&TA. 13).

33 K

C alarms tonsus. Three, immature.
Pseudocalanus elongatus 9 . One.
Metridia lucenstf. One.
Acartia longiremistf and 9 . Five.
Acartia tumida 9 . Three.
Harpacticus uniremistf and 9 . Eleven.

One female bearing ovisac was 1-20 mm. long, caudal setse 0-80 mm. ;
anterior antennae 9-jointed; p 1 with four biserrulate claws at end of Re and one
such claw at end of Ri. The terminal claw on p 1 Ri is accompanied by a falci-
form seta, which is often broken quite regularly at one spot, appearing as if
jointed (Fig. 47).

Fig. 47. H. uniremistf.
Terminal portion of p 1 Ri; from station 13.

The maxilla is like that of H. chelifer; B2 bifid, the rami one-jointed, Ri
trisetose, Re quadrisetose, the masticatory setse vaned (Fig. 48).

Fig. 48.
Maxilla.

H. uniremis.
Station 50d.

Second maxilliped: B2 with a proximal comb of spinules on its anterior
face (Fig. 49) and two combs on its posterior face, one proximal and one central,
as figured by Sars.

Station 14. See under Paralabidocera. One ovigerous female, length 0-96

mm

Station 410. Table XV. One example of 1 -36 mm.

69085—3

34 K Canadian Arctic Expedition, 1913-18

Station 42p. See under Pseudocalanus. Several examples comprising
and females. Length of one male 1-2 mm. When the body is viewed from the
side, without further preparation, it can be observed that the ectal spinules or
spinules on the outer surface of Re 1 in p2-p4 are arranged in three oblique rows:

Fig. 49. H. uniremis. First pair of legs and second maxilliped
(of right side) in position. Station 50d.

this is indicated in a figure by Sars. The anterior antennae of the male present
a distal expansion followed by a movable finger (dactylus) which is furnished
with a smooth spur projecting forwards, as described and figured by Sars; in
certain aspects the spur looks like the main body of the joint.

Station 50d. Young point, Dolphin and Union strait, Northwest Territories,
in beach water amongst algae, July 21, 1916. There were three Harpacticoids
in the vial, one Idycea furcata, and two H. uniremis 9 . One female carried an
ovisac, and there was a loose ovisac in addition; length of 9,1-3 mm. In the
thoracic legs, p 2 Ri 2 has two si; p 5 with 4 marginal spines on the inner
expansion and 5 on the distal lobe.

Sars finds that the H. chelifer var. arcticus described from Bering Sea on
floating kelp by S. A. Poppe (Arch. f. Naturgesch. 50, 1884) belongs to H.
uniremis. According to the same author, it is found along the whole Norwegian
coast, but only in depths of 20 to 100 fathoms. L. W. Williams found it in
Narragansett Bay abundant in tow-nettings in shallow water,1 and I have
found it amongst the stomach contents of the winter flounder at St. Andrews,
N.B. It has not been taken at Woods Hole.2

27. Idyaea furcata (Baird).

Station 20a. See Table IX. One female.

Station 40r. See under Acartia longiremis. Several ' females, one with
ovisac, 1-03 mm., another 1-00 mm., another 0-80 mm., and a fourth l-05mm.;
relative lengths of Th 5, Ab 1-4, and furca: 10, 15, 10, 9, 8, 6. The first and
second maxillipeds when seen in situ appear much alike, uncinate; the anterior
with larger claw, biarticulate; the posterior, three jointed, the claw itself having
an intercalary joint at its base.

Station 41s. See Table VI.

1 L. W. Williams: Notes on marine Copepoda of Rhode Island. Amer. Nat. 40, p. 653-4. 1906.
'<R. W. Sharpe: Copepoda of Woods Hole. Proc. U.S. Nat. Mus. 38, pp. 405-436, 1910.

Marine Copepoda 35 K

Station 42p. See under Pseuducalanus for position.

TABLE XVII (&PA. 42p).

Pseudocalanus elongatus. One 9 .

Eurytemora herdmani. Oned".

Oithona similis. Four.

Harpacticus uniremis. Seven (cf and 9 ).

Idycea furcata. Two 9 .

Danielssenia stefanssoni. Five females.

Length of one 9,1-2 mm., anterior antenna 8-jointed; setae with penicillate
tips on p 1 Re 3, p 1 Re 2, and p 1 Ri 3.

Station 42y. See Table X.

Station 422. Dolphin and Union strait, off Bernard harbour, depth 17
feet, ice 2J feet thick, midnight, water temperature 29-2° F., three vertical
hauls bottom to surface, December 12, 1915.

TABLE XVIII (&TA. 422).

Pseudocalanus elongatus, males and females.

Metridia longa, young (2-jointed urosome).

Acartia longiremis.

Onccea conifera, one female.

Idycea furcata, many young and adult.

There was a female with ovisac containing eggs in the first nauplius stage.
One male measure 0-88 mm. In immature Idycea furcata both the apical claws
of p 1 Ri 3 were observed to be penicillate; in the adult only the longer of the
two is penicillate.

Station 466. See under Oithona.

Station 46h. See under Oithona. Several immature examples.

Station 50d. See under Harpacticus uniremis. A single female with ovisac;
length 1-13 mm.

I have also found this species very abundant in the stomach contents of
the winter flounder at St. Andrews, N.B., associated with Harpacticus uniremis.

28. Dactylopusia signata, n. sp.

Station 40 c, d, e. See under Oithona.

Station 4 In. Bernard Harbour, Northwest Territories, depth 0-2 fathoms,
August 9, 1915; associated with Harpacticus superflexus, Amphiascus nasutus,
and Danielssenia stefanssoni.

Length of one female 0-8 mm., of another 0-63 mm. None was found
with ovisac and no male was observed. Rostrum blunt, conspicuous in side
view. Caudal rami very small, shorter than the anal segment, the innermost

Fig. 50. Dactylopusia signata.
Anal segment, caudal ramus and setae.

but one of the terminal setae on each ramus with a characteristic rounded pro-
tuberance near the base on the inner side. This ental protuberance of the caudal
seta is the chief distinctive mark, to which the specific name refers (Fig. 50).
69085— 3|

36 K Canadian Arctic Expedition, 1918-18

Anterior antennae 9-jointed, the 8th joint very small and a constant char-
ad eristic (Fig. 51). Mouth-parts normal; the first maxilliped is clawed like
,the second, its claw being longer and more powerful than that of mp2; t he-
basal joint of mp 1 has three inner setigerous lobes of which the proximal wa>
observed with a single long thick soft seta, the other two having more than one
seta at their apices.

Fig. 51. Dactylopusia signata. Anterior antenna.

The first thoracic legs are like those of D. thisboides and D. neglecta; Hi 1
with a plumose si at the centre of the joint. The outer distal angles of Re 1
and 2 of the natatory legs are not conspicuously produced, as they are in D.
thisboides. Second legs with setae as in D. thisboides; the ectal spinules of He
are coarser than those of Ri; B2 with slender se and triangular acute ental
spur, a feature also found in D. thisboides; in p2 Ri 2 the slender proximal si
arises distad of the centre of the joint. Third legs: B2 with still slenderer >c
and very small ental spur. In the fourth legs the Ri 2 has only one si and this
appears to be distinctive.

In the natatory legs p 2 to p 4 the terminal seta of the outer ramus is longer
than the entire ramus, in p 4 much longer. The se 3 has the same length as the
Re 3 in p 2 and p 4, a little shorter than the Re 3 in p 3.

The fifth legs appear to differ from D. thisboides in the interrelative lengths
of the marginal spines, but the general correspondence is remarkably close
(Fig. 52).

Fig. 52. Dactylopusia signata. Fifth leg.

It might be supposed that this species may be a submature " instar " of
D. thisboides , but the structure of the first antennas is hard to reconcile with
such a supposition. A word must also be said about the character of the caudal
seta, which seems at the surface to offer an unequivocal distinction. On
consulting Claus's work on the free-living Copepods (Leipzig, 1863) at a distance
from my material, I found an exactly similar condition of the setae figured
for Thalestris forficula Glaus. This species is now placed by Sars in a new genus,
Microthalestris, and nothing is said about the " kolbig angeschwollen " bases of

Marine Copepoda

37 K

the caudal setae, although a figure by Sars shows them slightly enlarged. A
similar condition, again, still more pronounced, is figured by Sars for Amphiascus
giesbrechti, but here the protuberance (s directed outwards.

Whatever may be the significance of this small tubercle on the caudal setae,
it is of some interest to find it occurring in three different genera.

29. Amphiascus nasutus (Boeck).

Station 4 In. See under Dactylopusia signata.

Station 43e. See Table VII.

This is, for its size, a stout harpacticoid with heavily built cylindrical
urosome. Length of female, 1-22 mm., of male, 0-72 mm. Caudal ramus
truncate, shorter than anal segment (Fig. 53).

Fig. 53. Amphiascus nasutus.
Anal segment and furca from below.

Anterior antennae distinctly 9-jointed, the proportional lengths of the
joints being: 7, 5, 5, 7, 2, 3, 1-5, 2, 4. Posterior antennae with Re three-jointed,
the middle joint short; Re 1 with one seta, Re 2 achaetous, Re 3 with one
proximal and two strong apical setae with several setules around their bases.
Second maxilliped with the si of the hand arising towards the distal end of the
joint.

Thoracic legs: p 1 with both rami three-jointed as in Dactylopusia, but
the si of Ri 1 is inserted near the distal end of the joint (Fig. 54).

Fig. 54. Amphiascus nasutus. P 1.

In the second leg (p 2), Ri 2 has two setae, Ri 3 has only four (1 se, 3si), in
place of the five in Dactylopusia (Fig. 55) ; B2 has a slender se and a short thorn-
like process in place of an si; outer distal angles of Re 1 and Re 2 are produced

38 K

Canadian Arctic Expedition, 1913-18

into two thick-based, somewhat blunt acuminations, that of Re 2 larger than
that of Re 1 (Fig. 56). In the fourth leg Ri 2 has only one si (Fig. 57); Re :>
only seven setae (3 se, 1 st, 3 si).

ss.

Fig. 55. A. nasulus 9 . p 2 Ri.
Fig. 56. Same, p 2 Re.
Fig. 57. Same, p 4 Ri.

The fifth legs (p 5 9 ) are highly characteristic, with a long and steep declivity
occupied by a few spinules, stretching between the two outermost spines of the
distal lobe (Fig. 58). Behind the innermost setae of the inner lobes there is
seen a chitinous thickening proceeding backwards from the genital opening.

Fig. 58. Amphiascus nasutus. p 5 9 .

In the male, the inner ramus of the second foot is transformed in an extra-
ordinary manner, as in the type figured by Sars.

30. Tachidius brevicornis Lilljeborg, 1853.

Station 4Qv. Creek mouth at Bernard harbour, Northwest Territories,
0-1 fathom, July 8, 1915.

The gathering consisted of seventeen small Harpacticoids, all of this species,
all females, and all, with one exception carrying an ovisac.

Length 0-76 mm.; eggs counted in five ovisacs: 39, 43, 44, 44, 53. Arrange-
ment of the setse on the rami of the natatory legs p 1 to p 4 and dorsal crescentic

Copepoda 39 K

spinulose anal valve as figured by Sars. In the first leg B2 has an ental spine
set upon a prominent rounded boss and an equal ectal spine on the anterior
surface (Fig. 59).

Fig. 59. Tachidius brevicornis.
First leg, anterior surface.

31. Danielssenia fusiformis (Brady).

I have identified a single individual of this species from Station 25 6, c, taken
at the surface close to ice, north of Cooper island, Alaska, August 27 and 28,
1913. l The length was about 0-85 mm. As a Danielssenia, its distinguishing
feature is the 5-jointed antenna, but in the specimen this is not so decisive as
could be desired. The terminal part of the antenna seems at a certain focus
to consist of two joints. The antennae carry a number of conspicuous thorny
bristles, three of which are especially prominent upon the basal half of the
terminal portion and one of them is inserted at the level where the articulation
should occur. This bristle was lost on one antenna and its sharply defined
broad base of insertion simulated an interarticular junction. The basal seta of
the posterior maxilliped was damaged accidentally in the manipulation. The
fifth foot accords with the figure by Sars.

Neither Brady nor Sars seems to be entirely satisfied as to the distinct-
ness of D. typica and D. fusiformis, and the differential characters advanced
by Brady are not those upon which Sars relies.

32. Danielssenia stefanssoni, n. sp.

Station 41n. See under Dactylopusia.

Station 41s. See Table VI.

Station 42p. Dolphin and Union strait, surface-tow, with net number 3,
10 minutes, Bernard harbour (outer harbour), water depth three fathoms,
September 30, 1915.

TABLE XIX (STA. 42p).

Pseudocalanus elongatus 12 (young and adult).

Eurytemora herdmani 3 (males).

Oithona similis 4.

Harpacticus uniremis H (males and females).

Idyceafurcata 2 (females).

Danielssenia stefanssoni 5 (females) .

Length of female, 1-226 mm. Rostrum prominent, defined behind. Caudal
rami slightly exceed anal segment as 10 : 9. Anterior antennae 6-jointed with
following relative lengths of joints: 13, 10, 7, 4, 5, 5. Posterior antennas with

i' See Table III.

40 K

Canadian Arctic Expedition, 1913-18

Re three-jointed; Re 1 carries a small proximal si inserted near the middle of
the joint, in addition to its distal plumose si; the distal joint of the Ri carries a
long spicate seta followed by three geniculate setae, then, near the inner distal
margin three strong spines; between the two subdistal spines of this group
there is a long curved claw, not described in other species (Fig. 60).

Fig. 60. D. si cfanssoni cf . Distal joint of inner branch of posterior
antenna, viewed from the mesial surface.

In the mandible, arising from a point near the middle of the Ri, there is a
group of three si instead of two si figured by Sars for D. fusiformis; observed
in both sexes. In the maxilla, the small club-shaped Re carries three long
plumose setae flaring apart as figured by G. S. Brady for D. fusiformis. The
armature of mp 2 differs from that of D. fusiformis, the two plumose setae of
the basal joint being inserted at the same transverse level instead of one behind
the other (Fig. 61).

Fig. 61. Posterior maxilliped. D. stefanssoni.

The thoracic legs of the female offer few distinguishing characters: p3
Re 3 has eight setae (3 se, 1 st, 4 si); p 3 Ri 3 has six setae (1 se, 5 si); p 4 Re 3

Fig. 62. D. stefanssoni 9 . P 3 Ri.

has eight setae; p 4 Ri 3 has five (Ise, 4 si). In the third foot (p 3) the outer
distal angle of Ri 2 is produced into a simple cone in place of the mucronate
process of the male (Fig. 62).

Marine Copepoda

41 K

In D. typica, as figured by Sars, and in D.fusiformis, as figured by Brady,
the Ri 3 of p 4 has four setae, there being only one seta arising from the centre
of the inner margin of the joint. In both sexes of D. stefanssoni there are t hree setae
at the apex of p 4 Ri 3, namely a short se and two longer si; on the inner margin
of the joint there are two more si, a proximal one arising from the middle of the
inner margin, and a distal one inserted between this and the apex of the joint.
In D. sibirica Sars, p 4 Ri 3 has six setse in the female, five in the male.

Fifth legs (p 69): hardly to be distinguished from D. sibirica, unless it is
by the interspacing of the marginal spines on the inner lamellar expansion ;
differing from D.fusiformis in the more proximal origin of the innermost mar-
-;inal spine of the inner lamella (Fig. 63).

Fig. 63. D, stefanssoni. Fifth leg of female.

In one case the distal joint of one side showed an aberration in the presence
of a long supernumerary spine at the inner side of the lobe, making a total of
six marginal spines instead of the normal number, five (Fig. 64).

Fig. 64. D. stefanssoni. Aberrant fifth foot of female.

In the male, the fifth legs are small, the rounded distal joint with five setae,
the reduced inner lobe with two unequal setse, as in D. typica.

Description of male; length 1-01 mm.; anterior antennas subcheliform, as
in D. typica, figured by Sars. The second thoracic leg (p 2) offers distinctive
characters in the presence of a powerful hamate process on the inner side

42 K

Canadian Arctic Expedition, 1913-18

Ri 1, and of a serrulate rostriform process of the reduced Ri 3; the subulate
process of Ri 2 is a generic character (Fig. 65 and 66).

\

Fig. 65. D. stefanssoni <?. P 2 Ri.
Fig. 66. Same. P 2 Ri 3 enlarged,

In the third leg of the male, Ri 2 is produced at its outer distal angle into
a strong mucronate process of rather complex form (Fig. 67). In the fourth
foot the distal angle of Ri 2 is produced into a slightly curved acuminate pro-
cess.

Fig. 67. D. stefanssoni <?. P 3 Ri.

The only other species with which the characters of the male D. stefanssoni
can be compared is D. sibirica G. 0 Sars (1898, Jana Expedition op. cit. p. 343).
The hamate process on p 2 Ri is common to both. On the other hand, in
D. sibirica the reduced Ri 3 of the second foot of the male is without a rostri-
form process. This is the cardinal distinction, the presence in the one and the
absence in the other of a sharply defined character. The anterior antennae in
the female of D. sibirica are five-jointed.

Marine Copepoda 43 K

D. MONSTRILLIDAE.

33. Thaumaleus bernardensis, n. sp.

Two males were taken at Station 422, December 12, 1915 (see under Pseu-
docalanus). Length of one male 1-9 mm., of the other 2-4 mm. The description
relates to the larger.

The head and first thoracic segment are fused together to form a cephalo-
thoracic segment which only slightly exceeds the next three segments (Th 2-4).
The lengths of the antennae, of the cephalothorax, and of the three free pedigerous
thoracic segments combined, are subequal, the proportions in the order named
being: 55 : 56 ; 53. The hind-body, comprising the apodous fifth segment
(Th. 5), the genital segment, two following segments and the furca, has the
relative length represented by the number 35. Thus the forebody is approxi-
mately three times the length of the hind-body. The anal or last abdominal
segment shows superficial indication of an imperfect division into two segments,
the same appearance being presented by both individuals. Counting it as one
segment, the caudal furca is a little shorter, in the ratio of 7 to nearly 8. There
is a very small papilla on the ventral side of Th. 5, representing a rudiment of
the fifth legs (Fig. 68).

The ventral lobes of the genital segment have the proportions shown in the
figure. Each caudal ramus carries four setae, the most ventral one being much
shorter than the others (Fig. 68).

Fig. 68. Thaumaleus bernardensis.
Hind-body of male.

The distance between the frontal margin and the mouth cone is less than
one-third of the distance of the latter from the hinder margin of the cephalo-
thoracic segment. On the ventral side of the head there are several chitinous
structures intervening between the anterior antennae and the rudimentary
mouth-cone. In front of the latter the cuticle is wrinkled, as mentioned by
Giesbrecht for Th. longispinosus, and the wrinkles terminate in a small papilla,

44 K

Canadian Arctic Expedition, 1913-18

which may represent a rudimentary (i.e., vestigial) labrum. In front of this
there is another median papilla of uncertain significance, and before this again
a pair of clear oval areas. At the base of each anterior antenna there is a small
transversely elongate chitinous thickening. Finally, on either side of the
supposed labrum there is a wrinkled papilla showing a small central cavity;
these are the possible vestiges of posterior antennae (Fig. 69).

Fig. 69. T. bernardensis. Ventral side of head.

The five antennary joints have the numerical proportions 8, 10, 5, 15, 16.
The fifth joint carries a strong, terminal claw-like seta, which can be held for-
wards or bent at a right angle to the joint. The following setae are to be found
at different points on the antennae : —

First joint: a subulate seta with short plumes.

Second joint: five shortly plumose subulate setae, of which three are to be
seen at the margin (Fig. 69), and in addition a long plumose seta arising dor-
sally at the distal margin, whose long plumes occur on the slender distal portion
of it.

Third joint: two long plumose setae and a shorter subulate seta beset with
fine points.

Fourth joint: sever, setae, including a slender aesthetask or sensory filament
and one long plumose seta: proximad of the long plumose seta are two marginal
subulate setae of which the proximal one is the longer; removed from the mar-
gin a little in front of the proximal subulate seta and proximad of the base of
the long seta is the aesthetask. In Th. longispinosus, Giesbrecht figures the
aesthetask alongside of the long seta. Distal to the base of the long seta is a
marginal subulate seta like the proximal one. Exactly opposite the base of
the long seta is a short subulate seta, and in front of this a precisely similar
one. In Giesbrecht's figure of Th. longispinosus, in place of the single marginal
proximal subulate seta, there are two equal setae side by side.

Fifth joint (Fig. 70) : there are three branched setae, a long plumose seta,
four soft slender setae which look like aesthetasks, a marginal and a subterminal
subulate seta and the terminal claw, making eleven altogether, as in Th. longi-
spinosus.

The swimming feet are all alike, both rami three-jointed, the Re with
1. 0, 1 se; 1, 1, 4 si; and one st. The st is plumose, like the others. The Ri
has 1, 1, 5 setae. The se of B2 is quite small and slender, longer on the third

Marine Copepoda 45 K

feet, as is the case in other species. In the males of Th. longispinosus and
thompsoni, there are only three si on the Re 3 of p 1, in addition to the st,
according to Giesbrecht.

Fig. 70. Th. bernardensis. Terminal portion of left antenna; only the
primary bifurcation of the branched setae is shown.

The material obtained by the Canadian Arctic Expedition constitutes an
imperfect index to the wealth of elemental life in the northern waters of Canada.
The Copepods, as a class, provide fish food for food fish. There is an inexhaust-
ible supply of this fish food in the Arctic ocean, whence it filters down into the
northern seas, where commercial fisheries are carried on. By tracing out
the southern extension of arctic and sub-arctic forms, a great deal has been
accomplished in giving precision to problems which await solution in the North
Atlantic. Similar exploratory and experimental work is required for the North
Pacific. In this way materials would be forthcoming which would enable the
age-composition of the different colonies of organisms on the sea-floor to be
made out. Equipped with such data we should be able to foretell the probable
incidence of lean years in the fisheries. With this information at their disposal
the capitalist corporations would be able to curb their tonnage so as to maintain
an economic equilibrium between the market and the deep sea. This is what
biological work can do for the deep sea and other fishery interests. Leaving
out of consideration the salmon family and some other anadromous fishes,
science cannot effectively replenish the stock of fishes in the sea, but it can claim
to predict the periodicity of fluctuations when the necessary data have been a< cu-
mulated after many years.

No epidemics affect the plankton, but we know that higher animals are
liable to various disorders and derangements whereby their numbers are reduced.
The presence of an abundant food-supply does not unfailingly attract a multi-
tude of feeders, and this fact, well-known to marine biologists and other natural-
ists, but not so well known to those who have had no actual experience in the
matter of the interdependence of organisms, indicates that while there is no
limit to the supply of primary food-stuffs in the sea, there are limits, in some
cases very narrow, in others very wide, but always very definite, to the valuable
species which subsist directly or indirectly upon this food.

Whilst investigating the distribution and periodicity of the food-organisms,
the biologist is brought into contact with the feeders, and though his methods
of extracting secrets from the sea may be slow, yet they are sure. Not sensa-

46 K Canadian Arctic Expedition, 1913-18

tional discoveries, but dogged perseverance, such as that exhibited to good
purpose by the members of the Canadian Arctic Expedition, should be en
couraged with a free hand, for the glory of Canadian science and the protection
of Canadian maritime industry.

MONTREAL, June 30, 1919.

Report of the Canadian Arctic Expedition, 1913-1918.

Volume I: General Introduction, Narrative, Etc.

Part A: Northern Party, 1913-18.

Part B: Southern Party, 1913-16. By Rudolph Martin Anderson. (In preparation).

Volume II: Mammals and Birds.

Part A: Mammals. By Rudolph Martin Anderson. (In preparation).
Part B: Birds. By R. M. Anderson and P. A. Taverner. (In preparation).

Volume HI: Insects.

Introduction. By C. Gordon Hewitt. (In press),
Part A: Collembola. By Justus W. Folsom. (Issued).
Part B : Neuropteroid Insects. By Nathan Banks. (Issued).

Part C: Diptera. By Chas. W. Alexander, Harrison G. Dyar, and J. R. Malloch. (Issued).
Part D: Mallophaga and Anoplura. By A. W. Baker, G. F. Ferris, and G. H. F. Nuttall. (Issued).
Part E: Coleoptera. By J. M. Swaine, H. C. Fall, C. W. Leng, and J. D. Sherman, Jr. (Issued).
Part F: Hemiptera. By E. P. Van Duzee. (Issued).
Part G: Hymenoptera and Plant Galls. By Alex. D. MacGillivray, Charles T. Braes, F. W. L. Sladea,

and E. Porter Felt. (Issued).
Part H: Spiders, Mites, and Myriapods. By J. H. Emerton, Nathan Banks, and Ralph V. ChamberUn.

(Issued) .

Part I : Lepidoptera. By Arthur Gibson. (Issued).
Part J: Orthoptera. By E. M. Walker. (In press) .
Part K: General Observations on Insect Life in the Arctic. By Frita Johansen. (In preparation).

Volume IV: Botany.

Part A: Freh water Algae and Freshwater Diatoms. By Charles W. Lowe. (In preparation).
Part B: Marine Algae. By F. Collins. (In preparation).
Part C: Fungi. By John Dear-ness. (In preparation).
Part D: Lichens. By K. L. Merrill. (In preparation).
Part E: Mosses. By R. S. Williams. (In press).

Volume V: Botany.

Part A: Flowering Plants and Ferns By James M. Macoun and Theodore Holm. (In preparation).
Part B: General Notes on Arctic Vegetation. By Frits Johansen. (In preparation).

Volume VI: Fishes, Tunleates, Etc.
Part A: Fishes. By F. Johansen. (In preparation).
Part B: Ascidians, etc. By A. G. Huntsman. (In preparation).

Volume VII: Crustacea.

Part A: Decapod Crustaceans. By Mary J. Rathbun. (Issued).
Part B: Schizopod Crustaceans. By Waldo L. Schmitt. (Issued).
Part C: Cumacea. By W. T. Caiman. (In press).
Part D: Isopoda. By Miss P. L. Boone. (In press).
Part E: Amphipoda. By Clarence R. Shoemaker. (In press).
Part F: Pycnogonida. Leon J. Cole. (In press).
Part G: Euphyllopoda. By F. Johansen. (In preparation).
Part H: Cladocera. By Chancey Juday. (In press).
Part I: Ostracoda. By R. W. Sharpe. (In preparation).
PartJ: Freshwater Copepoda. By C. Dwight Marsh. (Issued).
Part K: Marine Copepoda. By A. Willey. (Issued).
Part L: Parasitic Copepoda. By Chas. B. Wilson. (In press).
Part M: Cirripedia. By H. A. Pilsbry. (In preparation).

Volume VIII: MoDusks, Echinoderms, Coelenterates, Etc.
Part'A: Mollusks, Recent and Pleistocene. By Wm. H. Dall. (Issued).
Part B: Cephalopoda and Pteropoda. By S. S. Berry and W. F. Clapp. (In preparation).
Part C: Echinoderms. By Austin H. Clark. (Issued).
Part D: Bryozoa. By R. C. Osburn. (In preparation) .
Part E: Rotatoria. By H. K. Hairing. (In preparation).
Part F: Chaetognatha. By A. G. Huntsman. (In preparation).
Part G: Actinozoa and Alcyonaria. By A. E. Verrill. (In preparation).
Part H: Medusae and Ctenophora. By H. B. Bigelow. (In press).
Parti: Hydroids. By McLean Fraser. (In preparation) .
PartJ: Porifera.

Volume IX: Annelids, Parasitic Worms, Protozoans, Etc.
Part A: Oligochaeta. By Frank Smith and Paul S. Welch. (Issued).
Part B: Poly chaeta. By Ralph V. Chamberlin. (In, press).
PartC: Hirudinea. By J. P. Moore. (In press).
Part D: Gephyrea. By Ralph V. Chamberlin. (Issued).
Part E: Acanthocephala. By H. J. Van Cleave. (Issued).
Part F: Nematoda. By N. A. Cobb. (In preparation).
Part G: Trematoda. By A. R. Cooper. (In preparation).
Part H: Cestoda. By A. R. Cooper. (In preparation).
Parti: Turbellaria. By A. Hassell. (In preparation). f

Part J: Gordiacea.
Part K: Nemertini.

Part L: Sporozqa. By J. W. Mavor. (In preparation).
Part M: Foraminifera. By J. A. Cushman. (Issued).

Volume X: Plankton, Hydrography, Tides, Etc.

Part A: Plankton. Marine Diatoms. By Albert Mann. (In preparation).
Part B: Tidal Observations and Results. By W. Bell Daw«on. (In press).
PartC: Hydrography. (In preparation).