450 Wisconsin Academy of Sciences, Arts , and Letters ; 
The spines of the first basal segments of the male fifth feet 
are long and slender. The second basal segment of the right 
foot is nearly twice as long as wide. The lateral hair is long 
and slender and situated on the distal fourth of the segment. 
On the posterior surface not far from the middle line are two 
hyaline lamellae projecting inward. The proximal lamella 
is accompanied with a spine, and the distal lamella with a re¬ 
curved hook. The first segment of the exopodite is twice as 
long as broad, and has a blunt process on its outer distal angle. 
The second segment is twice as long as the first, is slender, 
very narrow at the proximal end, and grows gradually wider 
towards the distal end. The lateral spine is near the distal 
end, is rather long, and nearly straight. The terminal hook 
is very stout, almost conical in shape, and much shorter than 
the second segment. The endopodite is very small, appearing 
as a small process on the inner distal angle of the second basal 
segment. The length of the second basal segment of the left 
male fifth foot is a little less than twice its width. It is slightly 
concave on the outer margin. The lateral hair is situated well 
towards the distal end of the segment. The fiist segment of the 
exopodite is three times as long as wide, and somewhat concave 
on both the inner and outer margins. The distal inner angle is 
setose. The second segment of the exopodite is slightly concave 
on the inner margin, and is terminated with a finger-like proc¬ 
ess and a longer falciform spine. The endopodite is long and 
slender, reaching beyond the first segment of the exopodite, 
is obscurely two-segmented, and is setose at the tip. 
Length of female, 1.49 mm. Length of male, 1.325 mm. 
This was found in collections made by Professor Birge at 
Slidell, Louisiana. Only a few specimens were found, but it 
seems to be a well-marked species. It resembles in many re¬ 
spects D. Lintoni and D. stagnalis, but differs in some marked 
particulars. 
The noticeable points of difference from D. Lintoni are the 
form of the appendage of the antepenultimate segment of the 
right male antenna, the form of the terminal segment and hook 
of the right male exopodite, and the terminal setae of the en- 
