197 
date and situation. The food, on the contrary, was remarkably 
simple and uniform, consisting chiefly of* the larve of Neuroptera 
(eighty-four per cent.), of which Palingenia bilineata formed alto- 
sether the most important part (seventy-six per cent.),—the remain- 
ing eight per cent. being dragon-flies. A single small sucker (Catos- 
tomide), a few mollusks (Planorbis, young Unios and_ thin-shelled 
Anodontas), and some Aselli complete the brief dietary of this 
eroup. | 
It is not until we examine the food of full-grown specimens that 
we wholly appreciate the utility of the enormous crushing pharyn- 
geal jaws with their pavement teeth, found in this species. The 
entire food of the three large specimens examined, taken at Peoria, 
in April and October, proved to consist of mollusks only, including 
forty-six per cent. of the thick and heavy water snail, Melantho decisa, 
whose shell probably no other fish in our rivers could break. Cyclas, 
eat and undeterminable Gasteropoda composed the remainder 
of the food. 
