45 Canadian Arctic Expedition, 1913-18 
macrurus. Pl. 1, fig. 5, shows the first foot, and Pl. I, fig. 6 shows the fourth 
foot. Pl. I, fig. 7 shows the fifth foot of the female. 
The left male fifth foot, shown in Pl. I, fig. 8, is like that of L. macrurus. 
The exopodite of the right male fifth foot consists of three segments; the second 
segment has the customary spinous prolongation from the inner distal angle, 
anda hook-like spine on the outer distal angle. The third segment, situated 
just within the outer spine, is one-third to one-half the width of the second 
segment, is digitate, curved towards the inner margin of the foot, pointed at 
the extremity, and bears upon its dorsal surface a curved spine. It is distinctly 
separated from the second segment by a joint. 
Average length exclusive of furcal sete: females 2.99 mm., males 2.6 mm. 
This species was found only in the collections made at Collinson point, 
Alaskan Arctic coast, October 10, 1913, as a limnetic form under 10 inches of ice 
in a pond 4 feet deep on the coastal tundra. It is to be presumed that more ex-: 
tensive collections may show a wide distribution in the northern waters. 
Limnocalanus johanseni is readily distinguished from L. macrurus by the 
much shorter furcal rami which are armed only with fine cilia on the inner border 
and not covered with small spines or coarse hairs as in the former species. 
Four species of Limnocalanus have been described, macrurus Sars, sinensis 
Poppe, sarsit Daday, and grimaldii Guerne. Sinensis and sarsii are quite differ- 
ent from the other species in the structure of the male fifth feet, and Ekman 
(1905) has made the genus Gtgantella for sarsii, while Burckhardt (1913) has 
proposed the genus Sinocalanus for sinensis with the species sinensis Poppe, 
dérrii Brehm, and mystrophorus Burckhardt. In macrurus and grimaldii the 
structure of the male fifth feet is almost the same and in both the third segment 
of the right exopodite is indicated by a small tubercle on the second segment. 
The existence of a distinct third segment in johanseni separates this species 
definitely from the others. 
Genus Eurytemora. 
Specimens of Furytemora were found in the collections made at the following 
localities: Teller, Bering strait, Alaska, August 3, 1913; Martin point, Arctic 
coast of Alaska, July 28, 1914; Herschel island, Yukon territory, Canada, 
August 13, 1914; Bernard harbour, September 23, 1915; Bernard harbour, 
Oct. 6, 1915; Bernard harbour, Nov. 28, 1915; Bernard harbour, July 3, 1916; 
Bernard harbour, July 14, 1916. Most of the material was so immature that 
it was impossible to make specific determinations. In the collection of Sep- 
tember 23, 1915, from a brackish pond 4 feet deep, at Bernard harbour, how- 
ever, there was a large number of mature specimens of both sexes. It is from 
these that the following description is made. 
Eurytemora canadensis, n. sp. 
Plate I, figs. 9-12. Plate II, figs. 1, 2, 4, and 7. 
Frmatse.—The cephalo-thorax is oval in outline, the greatest width being 
forward of the middle. The last segment extends backward somewhat on the 
sides of the first abdominal segment, but is not produced laterally; the outer 
border of this segment is armed with a few minute hairs. The outline of the 
cephalothorax is shown in PI. I, fig. 9, and the outer border of the last segment 
in Pl. 1, fig. 12. The first segment of the female abdomen, shown in Pl. I, fig. 11, 
is somewhat expanded laterally, being about a third wider in the middle than 
at the ends. The first and third segments are of about the same length, and are 
one and one-half times the length of the second. The furcal rami are slender, 
about equal in length to the first two abdominal segments, and are ciliate on 
both inner and outer margins, except on that part of the outer margin distad 
of the lateral seta; these hairs are not only on the margin, but are present on 
