464 Illinois State Lahoratory of Natural History. 



and ephemerid larvcB had been eaten by only one or two 

 specimens each. The mollusks were more than two thirds 

 Sphseriurn, the remainder being Vivipara and Planorbis. The 

 Crustacea were chiefly crayfish, among them Cambarus virilis 

 and obesus. Besides these, I noticed Crangonyx, Allorchestes, 

 and Asellus, Cyclops and a few Cladocera (Simocephalus ameri- 

 canus^i Scapholeberis mucronatus, and Chydorus). 



FAMILY LEPIDOSTEIDuE. 



A half dozen of the river gars Lepidosteus platystomus 

 and L. osseus had eaten nothing but fishes, including the hick- 

 ory shad (Dorosoma), black bass (Micropterus), and some min- 

 nows (Cyprinidae). 



FAMILY POLYODONTID^. 



PoLYODON sPATHULA, Wall. Shovel-fish; Paddle -fish; 

 Spoon-bill Cat; Duck-bill Cat. 



This remarkable and most interesting fish, the most nota- 

 ble inhabitant of our waters, occurs abundantly in the Illinois, 

 Mississippi, and Ohio, but not elsewhere within our limits. It 

 has a more or less distinct habit of migration, being much the 

 most abundant in spring, although taken sparingly throughout 

 the remainder of the year. It is a gigantic species, reaching a 

 weight of thirty pounds and upwards, and a length of six feet 

 or more, including the paddle. It is now quite generally 

 dressed for the market, and sold at the same rate as catfish. 



It has an alimentary apparatus not less remarkable than 

 its other characters. The broad blade-like snout, the enormous 

 mouth and equally large gill slits, the efiicient branchial 

 strainer, and the peculiar structure of the intestine, — all in- 

 dicate a peculiar alimentary regimen and unusual feediug 

 habits. Both the upper and lower jaws of the young are pro- 

 vided with small, acute teeth — the upper with a band upon 

 the vomer and palatines, besides a row on the maxillaries, and 

 the lower with a longitudinal row extending nearly its full 

 length — but the jaws of the adult are toothless and smooth. 



