Marsh—North American Species of Diaptomus. 48$ 
long as wide, convex on both inner and outer margins, and 
with the inner margin setose. The second segment is slightly 
longer than the first, and armed with two setose pads on its 
inner margin. It terminates in a blunt digitiform process, 
and from the inner margin projects an acuminate, curved 
spine. The endopodite is slender, indistinctly two-segmented, 
reaches about one-half the length of the second segment of the 
exopodite, and is setose at tip. 
Length of female, 4 mm. Length of male, 3.5 mm. 
The original description was from material found in Fresno, 
California. It was' later reported by Brewer from Lincoln, 
Xebraska. These are thus far the only localities for the 
species, but doubtless it will be found at intermediate points. 
The description, as given above, is largely a compilation 
from DeGuerne and Bichard and Brewer, with such modifica- 
cations as a very limited personal acquaintance with the 
species has permitted. 
In the plate, the figures of the antenna and female fifth 
foot are from DeGuerne and Bichard, the male fifth foot from 
a preparation kindly loaned by Professor IT. B. Ward. 
diaptomus novamexicanus Herrick. 
Plate XXVI, figs. 0, 10. 
1895. Diaptomus novamexicanus Herrick, p. 46, figs. 27-29. 
•1895. Diaptomus novamexicanus Herrick and Turner, p. 70; 
pi. VI, figs. 7-10. 
1897. Diaptomus novamexicanus Schacht, p. 149. 
“A small species of robust form. Cephalothorax widest in 
front of the middle. The first segment equals in length the 
rest of the cephalothorax. The last segment is armed on each 
side with a minute spine. 
“The first abdominal segment of the female exceeds in length 
the rest of the abdomen. It is dilated laterally, and armed on 
each side with a small spine. The second segment is very 
short. The furcal rami equal in length the preceding segment. 
The furcal setae are short. 
