The Food of Fresh-Water Fishes. 448 



Pharyngeals moderately heavy, the teeth about forty-five 

 on each side, the lower ten thickened and broadened, with 

 smooth terminal edges, but alternately higher and lower in the 

 specimen examined. The other teeth are hooked at the 

 anterior angle, and irregularly crenate on the cutting edge. 

 The intestine is small, one and a fourth times the length of 

 the head and body. 



The salient features of the food of Moxostoma macrolep- 

 idotuiii, as exhibited by twelve specimens examined, are the 

 abundance of univalve Mollusca and the bivalve Sphaerium, 

 the insignificance of the vegetable element, and the absence of 

 Crustacea and the larger and more active insect larvas. The 

 insect food consisted almost wholly of larvae of Chironomus 

 and other small mud-inhabiting species. 



The molluscan food, taken by eleven of the twelve specimens, 

 amounted to more than half the total, the principal forms 

 represented being Vivipara and Melantho (twenty-two per 

 cent.), Somatogyrus and Amnicola (six per cent.), and the fol- 

 lowing pulmonates, — Limnea, Physa, and Planorbis. Three of 

 the specimens had eaten Spha?rium, but the Unionidffi were 

 only doubtfully represented. The insects — about one third 

 the food — were practically all aquatic, and nearly all dipterous 

 larvEe. Two specimens, however, had taken a small quantity 

 of hydrophilid larvae, one an Agrion larva, and two others 

 larvffi of Ephemeridaj. The Entomostraca recognized belonged 

 to Alona and Cyclops. The vegetable food consisted of distil- 

 lery slops, eaten by one of the specimens, with a little Wolifia, 

 Chara, filamentous Algaj, and some miscellaneous matter. 



This group of specimens was taken from the Illinois River 

 at Henry, Peoria, Pekin, and Havana, and from Crystal Lake 

 in northern Illinois, at dates ranging from May to November 

 of four different years. 



Five additional examples of this genus, the species of 

 which was not determined but which almost certainly belonged 

 to macrolepidotum^ had eaten a still larger ratio of Mollusca 

 than the preceding group, these making now three fourths 

 of their food, — the greater part Sphaerium. Melantho. and 

 Amnicola also occurred, the former making one fourth of the 

 food of the five. 



