(82) 



and other dragon flies, May flies, caddis flies), water bugs, 1 (Corixa and 

 Notonecta), vegetable matter 4, (algae, Naiadaceae, roots stems and leaves 

 of various plants). 



51. Black Cat Fish. Amiurus melas, Raf. (2). Taken in small 

 prairie creeks, McLean Co. Stomach of one was full of purely vegetable 

 food, consisting chiefly of a mass of confervoid algae ; that of the other con- 

 tained no vegetation, but exhibited fragments of various insects, some of 

 them terrestrial, and remains of young craw-fishes and aquatic larvae. 



DOG FISHES. AMIIDAE. 



52. Dog Fish. Grinnel. Amia calva, L. (1.) A single small spec- 

 imen, 5 in. long, from S. 111., had eaten some Ephemera larvae, a few ostra- 

 coda (Cypris) and some confervoid algae, with numerous diatoms. 



GAR PIKES. LEPIDOSTEIDAE. 



53. Broad-nosed Gar. Lepidosteus platystomus, Raf. Seven or 

 eight specimens were opened, but the stomachs of all but one were entirely 

 empty. This one contained a common river craw-fish, (Cambarus immunis, 

 Hagen.) Is the gar a nocturnal feeder? 



SPOON-BILLED CATS. POLYODONTIDAE. 



54. Shovel Fish. Bill Fish. Polyodon folium, Lac. ( 5.) This is 

 by far the most remarkable fish in our rivers, and is not less remarkable in 

 its food than its structure. By the fishermen it is supposed to live on the 

 slime and mud of the river bottom. The alimentary canal of each of the 

 five specimens examined was found full of a brownish, half fluid mass, 

 which, when placed under the microscope, was seen to be made up chiefly 

 (in one case almost wholly) of countless myriads of entomostraca, of nearly 

 every form known to occur in our waters, including many that have been 

 seen as yet nowhere but in the stomachs of these fishes. Mixed with these, 

 in varying proportion, were several undetermined and probably undescribed 

 species of water worms (Annulata), most of them belonging to the family 

 Naididae. Sometimes as much as a fourth of the mass was composed of 

 vegetable matter, — largely algae, but including fragments of all the aquatic 

 plants known by me to occur in the waters of the Illinois, except Cerato- 

 phyllum. Occasional leeches (Clepsine), water beetles (Coptotomus inter- 

 rogatus &c.), a few larvae of diptera and Ephemerae and water bugs (Corixa) 

 were noticed. Among the Crustacea several specimens of the remarkable 

 Leptodora hyalina already referred to were found. 



I have not had time for anything more than a general examination of 

 the mass of matter presented, — sometimes more than a pint from a single fish, 

 — and cannot, therefore, give a list of the species. Curiously, very little 

 mud was mixed with the food. 



