464 Wisconsin Academy of Sciences, Arts, and Letters. 
line lamella, the endopodite is longer and is sometimes indis¬ 
tinctly two-segmented. The left endopodite is very much 
shorter in D. washingtonensis . 
DIAPTOMUS JUDAYI Sp. nOV. 
Plate XXII, fig. 6. Plate XXIII, figs. 1, 5. 
A small species. The first cephalothoracic segment is con¬ 
siderably longer than the three following. The last segment 
is armed with minute lateral spines. 
The first segment of the female abdomen is longer than the 
rest of the abdomen. It is expanded laterally and in front 
and bears two small lateral spines. On the posterior end of 
the right side it bears a finger-like process projecting backward. 
This process is somewhat shorter than in the other species of 
the signicauda type. The second segment is about half the 
length of the third. The furcal rami are rather less than 
twice as long as their width, and are ciliate on the inner mar¬ 
gin. 
The antennae are 2 5-segmented and extend a little beyond 
the furcal rami. The right antenna of the male is much swollen 
anterior to the geniculating joint, and bears a straight process 
on the antepenultimate segment. This process is two-thirds 
the length of the penultimate segment. 
The first basal segments of the female fifth feet are armed 
with the customary spines. The second basal segments have 
rather long lateral hairs. The exopodite is composed of tw T o 
segments, the third segment being represented by two spines. 
The second segment is prolonged into the usual hook-like proc¬ 
ess, and is denticulate on the inner margin. The endopodite 
about equals in length the first segment of the exopodite, is 
armed on the inner margin of the tip with hairs, and has two 
rather long terminal spines. 
In the fifth feet of the male, the first basal segments are 
armed with rather large spines. The second basal segment of 
the right foot is trapezoidal in form and considerably longer 
