20 Bulletin Wisconsin Natural History Society [Vol. 13, No. 1 
longer than the first, is curved outward, and bears three spines on its outer 
margin, the inner one being the longest. The two inner spines represent 
the third segment. The endopodite is somewhat longer than the first seg- 
ment of the exopodite, is not distinctly segmented, and bears two spines 
about equal in length on its outer margin near the end. 
Fifth feet of male. — Each of the first basal segments bears a minute spine 
and each of the second segments bears a lateral seta (fig. 3, A). The second 
basal segment of the right foot is somewhat longer than broad, with a 
broadly rounded prominence at the proximal inner angle (3, A). The first 
segment of the exopodite is broader than long and somewhat produced at 
the inner distal angle. The second segment of the exopodite is somewhat 
longer than the two preceding segments. It is broadest a little beyond 
the middle and the lateral spine is situated at the widest portion. The 
terminal hook is about one and a half times as long as the two joints of the 
exopodite together and is recurved at its outer extremity. 
Fig. 3. Diaptomus pribilof ensis n. sp. Fifth Feet of the Male. B, 
Showing Details of Right Foot. 
The right endopodite is small, acuminate, and shorter than the first 
joint of the exopodite (fig. 3, B). 
The inner margin of the second basal segment of the left fifth foot is 
broadly conical in form, the apex being near the middle of the joint. The 
conical portion sometimes shows a groove, thus giving it a bilobed appear- 
ance. The first segment of the exopodite is about as broad as long. It is 
convex on its outer margin and about straight or slightly concave on its 
inner margin. The terminal segment is somewhat longer than broad, with 
a large setose pad on its inner margin. It terminates in two finger-like 
processes which are equal in length. 
The endopodite is long and slender, and is not distinctly segmented. 
It is pointed and setose at the end. 
Length, cf 1.25-1.3 mm., $ 1.35-1.45 mm. 
This species appears to be most closely related to D. theeli, with 
which it has certain features in common, such as the lobate proc- 
