Food /fi'fftfinnx of /'Vrs//-ir<//fr Fishes. 491 



ble average in the food of thirty-three specimens being seven- 

 teen per cent. Plant structures made about one fourth the 

 food of seven sticklebacks. 



Certain of the suufishes evidently take plant food pur- 

 posely, on occasion, this making, for example, nearly a tenth 

 of the food of forty-seven specimens of Lepomis. Among the 

 larger fishes, the principal vegetarian is the gizzard shad, in 

 which this element was reckoned at about a third, taken, 

 however, not separately, but with quantities of mud. A con- 

 siderable part of it was distillery slops obtained near towns. 



The buffalo fishes are likewise largely vegetarian, more 

 than a fourth of their food coming from plants, about a 

 third of this in our specimens, refuse from distilleries. Vege- 

 tation made a tenth of the food of the larger genera of cat- 

 fishes (Amiurusand Ictalurus), some of it distillery refuse, 

 and nearly as large a ratio of that of the great Polyodon. 



Not infrequently, terrestrial vegetable rubbish seeds of 

 grasses, leaves of plants, and similar matter was taken in 

 quantity to make it certain that its appropriation was not acci- 

 dental. 



Besides a great variety of Alga3, both filamentous and uni- 

 cellular, including considerable quantities of diatoms, the prin- 

 cipal plant forms found in the food of fishes were the duck- 

 weeds Lemna and Wolffia. The deep-bodied suckers, especially, 

 occasionally take quantities of these little plants during the 

 autumnal months. 



MUD. 



The principal mud-eating fishes are the gizzard shad, the 

 common shiner, and the genera of minnows belonging to the 

 groups with elongate intestines and cultrate pharyngeal teeth; 

 viz., Pimephales, Hybognathus, Chrosomus, and Campostoma. 

 Much mud was taken also by the cylindrical members of the 

 sucker family, but apparently as an incident to their search for 

 mollusks. 



