508 
Fig. 4. Eurytemora yukonensh n. sp. Copepodid stage 
V. a. Female, leg 5 with detail of apex of exopod; 
Z’j male, leg 5, posterior view. 
lEurytemora spec. Kiefer, 1938: 78, figs. 
1-3 (d^). 
SPECIMENS EXAMINED. One 9 . Tundra pond 
(brackish.^) near Unalakleet, on Norton 
Sound, western Alaska, August 7, 1951, C. 
O. Berg. 
Five 9 (4 ovigerous),8 cf , 21 copepodids. 
Pond (fresh water which might become brack- 
ish at times). Boxer Bay, southwest cape of 
St. Lawrence Island, Bering Sea, Alaska, July 
6, 1952, F. P. Pauls. 
DESCRIPTION OF ALASKAN SPECIMENS. 
Female: Total length dorsal mid-line: St. Law- 
rence Island specimens 1.21-1.46 mm.; Un- 
alakleet specimen 1.41 mm. (metasome 0.68, 
urosome 0.55 mm.). Body form in dorsal view 
PACIFIC SCIENCE, Vol. VII, October, 1953 
similar to that of yukonensis. Relative lengths 
of the segments: 
1 2 3 4 5 6 
110 50 40 32 15 9 
Greatest dorsal width of metasome in seg- 
ments 2 and 3 (Unalakleet specimen 0.37 
mm.; reduced to 0.295 mm. in segment 5). 
First segment in lateral view (Fig. 6) showing 
no cephalic depression or medial dorsal pro- 
tuberance. Wings of sixth segment a little 
asymmetrical, each with well-developed, 
rounded inner lobe; outer portion produced 
into outwardly and backwardly directed pro- 
trusions reaching about to middle of genital 
segment and armed with scattered hairs. 
Urosome equaling 39 per cent of total 
length. Relative lengths of urosome segments 
(mid-line) and caudal rami, exclusive of setae: 
1 2 3 CR 
46 27 31 60 
Genital segment constricted in the middle, 
upper part with nearly symmetrical, rounded 
lobes produced laterally beyond those of dis- 
tal part, armed marginally with hairs. Genital 
operculum conspicuous in lateral profile (Fig. 
6d), occupying a comparatively large part of 
ventral area which is without cuticular folds 
or tumid protrusions. A heavy, sclerotized, 
semicircular line encloses area of receptacula, 
portion of operculum distad to this consists 
of a large, rounded flap. 
Fig. 5. Apex of mandible blade, female, a, Eury- 
temora yukonensis n. sp.; b, Eurytemora composita Keiser. 
