120 
stomach of the largest specimen consisted of Cyclops, and five per 
cent. of Chironomus larve. Consistently with the small mouth and 
pointed pharyngeal teeth, no traces of fishes or mollusks were found 
in the food. 3 
é 
Pomoxys NigRomAcuLATus, Lac. Brack Croprre. Lake Croppre. SInvER 
Bass. Butrer Bass. 
Pomo:ys ANNULARIS, Raf. Wutre Croprre. Timeer Croprre. Srinver 
Bass. 
These two species, often not distinguished even by experienced fish- 
ermen, 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 fam- 
ily, excepting the black bass. They are nowhere else ‘so abundant 
in the State, although occurring in the larger rivers generally and 
in the great lakes. The first species is commonest to the north, 
and the second southward, as far as my observation goes. In the 
Illinois, they are about equally abundant. These fishes are every- 
where 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 main- 
tenance. 
The gill-rakers of this species are numerous, long and finely- 
toothed, constituting the most efficient straining apparatus to be 
found among the sun-fishes. The pharyngeal teeth are sharp, and 
the mouth is rather wide and considerably enlarged by the length- 
ening of the lower jaw. 
Consistently with the hypothesis concerning the meaning of the 
gill-rakers which I had already formed from a study of the pre- 
ceding species, before 1 came to this, I found that the young con- 
tinued to feed almost exclusively upon Entomostraca much longer 
than the other sun-fishes. Six specimens between three and four 
inches long, had eaten little else than Entomostraca and the larvae 
of minute Diptera (Chironomus and Corethra). Even full-grown 
specimens were found eating Cladocera more freely than any other 
food. As might be inferred from the pharyngeals, not a trace of 
molluscan food was found in the forty-two specimens examined, 
while fishes formed nine per cent. of the food of the twenty-seven 
adults. Most of these were eaten late in the season, when Ento-— 
mostraca and insect larve became less abundant. 
Food of the Young. 
The smallest specimen, three-fourths of an inch long, had eaten 
about equal quantities of Cyclops and Simocephalus, with only a 
few Pleuroxus beside. Three, an inch long and under, had con- 
fined their food entirely to Entomostraca and Chironomus larve,— 
the latter forming about a fourth of the whole. A third of the 
Entomostraca were Cyclops, the remainder chiefly Simocephalus. 
