The Food of Fishes. 61 
addition of considerable quantities of terrestrial and 
aquatic insects. 
The gill-rakers of this species are numerous, long and 
slender — a fact reflected in the food. Fifteen per cent, 
of the contents of the stomach of the largest specimen 
consisted of Cyclops and five per cent, of Chironomus 
larvae. Consistently with the small mouth and pointed 
pharyngeal teeth, no traces of fishes or mollusks were 
found in the food. 
PoMOXYS .NIGROMACULATUS, Lac. BLACK CrOPPIE. Lake 
Croppie. Silver Bass. Butter Bass. 
Pomoxys annularis, Baf. White Croppie. Timber 
Croppie. Silver Bass. 
These two species, often not distinguished even by ex- 
perienced fishermen, agree so closely in food that I have 
not thought it worth while to treat them separately. In 
the Illinois and Mississippi rivers they are much the most 
valuable and important of the family, excepting the black 
bass. They are nowhere else so abundant in the State, al- 
though occurring in the larger rivers generally and in 
the Great Lakes. The first species is commonest to the 
north, and the second southward, so far as my observation 
goes. In the Illinois they are about equally abundant. 
These fishes are everywhere great favorites, and rank 
among the most important and promising of our smaller 
species. They are rarely found in creeks or small ponds, 
but seem to require deeper water for their maintenance. 
The gill-rakers of this species are numerous, long, and 
finely toothed, constituting the most efficient straining 
apparatus to be found among the sunfishes. The pharyn- 
geal teeth are sharp, and the mouth is rather wide and 
considerably enlarged bv the lengthening of the lower jaw. 
Consistently with the hypothesis concerning the mean- 
ing of the gill-rakers which I had already formed from a 
study of the preceding species, before I came to this, I 
found that the young continued to feed almost exclusively 
upon Entomostraca much longer than the other sun- 
fishes. Six specimens between three and four inches long, 
