Marsh—North American Species of Diaptomus. 405 
opodite is near the proximal end, the anten¬ 
nal process is dentate on the outer margin, _... Trybomi 
Right endopodite about equals in length the first 
segment of the exopodite, lateral spine median,. Judayi 
The process of the antepenultimate segment of the 
right antenna nearly equals or equals the penul¬ 
timate segment, 
The right endopodite equals in length the first seg¬ 
ment of the exopodite, spines of the first basal 
segment large, . tenuicaudatus 
The right endopodite exceeds the length of the 
first segment of the exopodite, spines of the 
first basal segment small, . sicilis 
The process of the antepenultimate segment of the 
antenna exceeds in length the penultimate seg¬ 
ment, 
Large. Lateral spine of the second segment of the 
male exopodite is terminal or nearly so, 
The antennal appendage only slightly longer than 
the penultimate segment, antennae equal in 
length to cephalothorax, . shoshone 
Antennal appendage exceeding in length the ul¬ 
timate segment, antennae reaching the furca, . Wardt 
Small. The lateral spine of the second segment of 
the right exopodite is on the proximal half of 
the segment, the antennae reach beyond the 
furca. 
Lateral spine of the second segment of the right 
exopodite short, right endopodite rudimentary, ... .mirmtus 
Lateral spine long, right endopodite equals in 
length the first segment of the exopodite, . Ashlandi 
The antepenultimate segment of the right antenna bears 
a curved process, 
The appendage equals or exceeds in length the penul¬ 
timate segment, 
The appendage about equals in length the last two 
segments, the second basal segment of the 
right foot is dilated on the inner margin, the 
endopodites are two-segmented, . Eiseni 
The appendage slightly exceeds in length the penul¬ 
timate segment, second basal segment of the 
right foot not dilated on the inner margin, the 
left endopodite one-segmented, . franciscanus 
The appendage is shorter than the penultimate seg¬ 
ment. 
One or both terminal processes of the last seg¬ 
ment of the left exopodite are distinctly falci¬ 
form, 
