406 Wisconsin Academy of Sciences, Arts, and Letters. 
The right endopodite is small, shorter than 
the first segment ( of the exopodite. 
Terminal segment of the right exopodite is 
elongate, 
Right endopodite rudimentary, left endopo¬ 
dite 2-segmented, spatulate in form,_ spatulocrenatus 
Terminal segment of right exopodite much 
the broadest at the distal end, lateral 
spine nearly terminal and straight, 
left endopodite elongate, . conipedatus 
Terminal hook of right exopodite falci¬ 
form, lateral spine at the distal third 
of the segment, second basal segment 
of the right foot broad at the distal 
end with process at the external distal 
angle, . sanguineus 
Terminal segment of right exopodite of usu¬ 
al length, 
Lateral spine terminal, 
Inner surface of left endopodite rugose, 
a very large species, . stagnalis 
Segments of right foot short and broad, 
terminal hook long and strongly 
curved, lateral spine long and 
straight, . saltillinus 
The right endopodite is distinctly longer than 
the first segment of the exopodite, 
The first segment of the right exopodite has an 
oblique ridge on its dorsal surface. 
The first segment of the right exopodite has 
a transverse ridge, the lateral spine of the 
terminal segment is about one-half as 
long as the segment,. aspmmetricus 
The first segment of the right exopodite has 
two curved processes on its dorsal surface, 
the lateral spine of the terminal segment 
equals or exceeds in length the segment, . dorsalis 
The first segment of the right exopodite does 
not have a transverse ridge on the dorsal 
surface. 
The lateral spine of the terminal segment of 
the right exopodite is terminal, the en- 
dopodites are distinctly two-segmented, . Bakeri 
The lateral spine is situated on the distal 
third of the terminal segment of the right 
exopodite, the right endopodite is indis- 
