(89) 
not hitherto reported. The following is Say’s description, in Jour. Acad. 
Nat. Science, Phil., Vol. I, p. 440, 1818 : 
“ D . angulata. Body viewed laterally, sub-oval, contracted before, 
gibbous above near the posterior edge, beneath ventricose in the middle ; 
back sub-ovate, acute behind and contracted before : sides striate with nu- 
merous minute, parallel, obliqe lines. Hind edge of the body with a prom- 
inent angle in the middle, which is obtuse at tip ; above the angle it is 
ciliated. Antennae, 4 filaments on the superior branch, and 5 on the in- 
ferior branch j color white or red. Length -jL- of an inch. Cabinet of the 
Academy. Very common in the stagnant marsh water of the forests of the 
Southern States.” 
In the Illinois specimens the head is marked off from the body by a 
dorsal indentation. The color is usually white. Found in the stomachs of 
carp, buffalo, sun-fish, &c. It constituted the principal part of the food of 
a number of croppies taken in April, from the Illinois R. The eggs be- 
neath the carapace were so numerous as to give an orange color to the 
whole mass of the food at this time. 
Daphnia pulex I L. 
The species referred to by Prof. Smith, under this name,* is our com- 
monest Daphnia , occurring everywhere in immense numbers. It is eaten 
by Polyodon and by many small fishes. 
Daphnia galeata , Sars. 
A species probably the same as that figured by Prof. Smith in the paper 
already cited, was found in Crystal Lake, — a shallow sheet of water about 2 
miles long — and was eaten in numbers by the abundant little silversides 
( Labidesthes .) 
Canthocamptus illinoisensis , Forbes. 
This minute crustacean was frequently found in carp, buffalo and shovel 
fishes from the Illinois R. 
Diaptomus sanguineus, Forbes. 
In Pomoxys nigro-maculatus. Numbers of the genus unrecognizable 
as to species were observed in a variety of fishes. 
Many Cyclops and Cypris, the species of which I have not attempted to 
discriminate, occurred in fishes from all waters and of a dozen families. 
Loc. cit. 
