The Food of Fresh- Water Fishes. 439 



Cypris, one Cyclops, and two Alona. The vegetable food of the 

 group amounted to thirty-two per cent., eaten by all the speci- 

 mens. Beside the distillery slops already mentioned, Lemna, 

 WolfBa, various diatoms and other unicellular plants, and oc- 

 casionally filamentous Alga3, were noted in the food. It is 

 probable that in some situations and at some seasons of the year, 

 Entomostraca would be found a more important element; other- 

 wise one can hardly see the advantage of the excellent bran- 

 chial strainer borne by this species. The great length of the 

 intestine and the unusual development of the mucous surface 

 are seemingly correlated here, as among the cyprinoids, with 

 the limophagous habit. 



In five specimens, two and a half inches in length, the 

 food was intermediate in character between that of the adult 

 and that of the young, about sixty per cent, of it being Algai, 

 mixed with an abundance of dirt, and the remainder Cladocera 

 (twenty-two per cent.) and insect larva3 — about half of them 

 Chironomus. 



A single specimen, five and a fourth inches long, had fed 

 principally on Entomostraca (Bosmina, Daphnia, and Cyclops), 

 with a very few Chironomus larvae. 



FAMILY OLUPEID^. 



Only a single species of the herring family occurs in this 

 State — the golden shad, Clupea cJirijsochloris^ Raf. — and this not 

 by any means commonly with us. It seems to be strictly pre- 

 daceous, the three specimens taken by me at Pekin and Peoria 

 in September and October of three different years having eaten 

 only fishes — two of them the gizzard shad (Dorosoma) and 

 the third some undetermined kind. A single small specimen, 

 two and a fourth inches long, had fed wholly upon terrestrial 

 insects, among which were noticed Triphleps insidiosiis, aspecies 

 of Typhlocyba, a chalcid (Eurytoma), small Diptera (including 

 Culicidae and Muscidae), and some small spiders. 



