1915] 
Juday AND Muttkowski: Alaskan Entomostraca 
25 
ence seems to be constant and is probably sufficient to give this 
form a varietal rank. 
In the female the two-jointed appendage of the fifth feet will 
serve to distinguish this form from D. shoshone females. 
The species is very abundant in the St. Paul Island material. 
Diaptomus pribilofensis nov. sp. 
This is a small species. The suture of the first cephalothoracic segment 
is fairly distinct; this segment is about as long as the three following ones. 
The last thoracic segment bears two lateral lobes which are pointed at their 
outer extremities (see fig. 2, B and C). The male has smaller lateral lobes 
than the female. 
Fig. 2. Diaptomus pribilofensis n. sp. A , Fifth Foot of Female; 
B, Abdomen of Female; C, Abdomen of Male. 
The antennae reach to the end of the furca or slightly beyond. The 
antepenultimate segment of the right male antenna bears no appendage. 
The abdomen of the female is rather long (fig. 2, B), the first segment is 
about twice as long as the second and third combined, moderately dilated 
anteriorly, and bears two lateral spines near the posterior edge of the dilated 
portion. The second segment of the abdomen is very short, distinctly 
shorter than broad. The third segment is about as long as broad. The 
furcal rami are about as long as the third segment of the abdomen. 
Fifth feet of female. — The first basal segment bears a small spine on the 
posterior surface, the second basal segment is rather short and slender, 
and bears a lateral seta (fig. 2 , A). The first segpaent of the exopodite is 
a little more than twice as long as wide. The second segment is one-third 
