The American Naturalist. [April,. 
296 
Pleuroxus procurvus Birge. 
Chydorus sphericus O. F. Miiller. 
Camptocercus rectirostris Schcedler. 
Polyphemus pediculus Linnzus. 
MANITOBA. 
LAKE 
DESCRIPTION OF A NEw SPECIES. 
CERIODAPHNIA ACANTHINA. 
Bosmina longirostris O. F. Müller. 
Chydorus sphæricus O. F. Müller. 
Leptodora hyalina Lilljeborg. 
The body is large, rounded, with the valves of the shell 
forming a well developed posterior s 
ated from the body by a very deep 
The head is separ- 
Head is low, 
pine. 
depression. 
Ceriodaphnia acanthina ? 
KA 
fe 
small, rounded in front of the eye, sinuous above and angled 
between the eye and the antennules; the lower margin 1s 
nearly in a line with the lower margin of the valves of the 
- shell. 
