198 Wisconsin Academy of Sciences, Arts, and Letters. 
somewhat shorter than the first segment of the exopodite. It is 
setose at the tip, and armed with two long terminal spines 
which are inserted well back from the end of the endopodite. 
In the male fifth foot, (Plate X, fig. 7) the spines of the first 
basal segment are rather prominent and acute. The second 
basal segment of the right foot is about twice as long as broad; 
the lateral hair is situated a little beyond the middle of the seg¬ 
ment. The first segment of the exopodote is quadrate, slightly 
longer than broad, and bears two curved hyaline processes, one, 
which is quite prominent, on the inner distal angle, and the 
other, much smaller, on the distal posterior edge. The second 
segment is more than twice as long as broad, is nearly straight, 
and is of about the same width throughout. The lateral spine 
is small, curved, and situated distad of the middle. Hear the 
inner margin on the posterior surface is a small spine reminding 
one of the similar structure in the oregonensis group, although 
less pronounced. The terminal hook is rather stout, slightly 
curved, and, in length, exceeds, a little, the rest of the exopo¬ 
dite. It is finely denticulate on the inner margin. The right 
endopodite nearly equals in length the first segment of the ex¬ 
opodite. It is somewhat variable in shape, but is ordinarily 
rather broad and pointed at the tip. The end is armed with 
minute setae. The left foot reaches to the end of the first seg¬ 
ment of the right exopodite. The second basal segment is as 
long as wide. The inner margin is strongly convex, and near 
this margin, about midway of the segment, is a small blunt 
spine. The lateral hair is situated near the distal end of the 
segment. The first segment of the left exopodite is longer than 
wide, its length in some cases being more than twice its width. 
The second segment is about two-thirds as long as the first, and 
has upon its inner surface a convex setose pad.; the segment is 
terminated with two digitiform processes, of which the outer is 
the longer. The endopodite is slender, one-segmented, more or 
less pointed, and reaches to about the middle of the second seg¬ 
ment of the exopodite. The tip is distinctly setose. 
Length of female 1.88 mm. Length of male 1.32 mm. 
This has been found at Corona, Kremmling, Tolland, and 
Mount Carbon, Colorado. 
