18 FISHES OF ILLINOIS 



mention of the paddle-fish is by P ere Marquette (1673-1677), who 

 described it as a remarkable fish, resembling a trout with a large 

 mouth. " Near its nose * * is a large bone shaped like a 

 woman's busk, three fingers wide and a cubit long, at the end of 

 which is a disk as wide as one's hand." — Jesuit Relations, LIX., p. 

 111. Edition Thwaites. 



Although the paddle-fish frequents waters with a muddy bottom, 

 the relatively minute size of many of the objects on which it feeds, 

 the absence of mud from its intestine, and its seeming preference for 

 animal food, indicate that it is not only able to gather large quanti- 

 ties of very minute objects from among the weeds and from the 

 muddy bottom, without filling itself with mud, but that it can 

 separate the Entomostraca from the algas among which the}^ swim. 



The facts concerning the food of this fish were first ascertained 

 and published by the senior author in 1878,* and were studied again 

 more extensively by him in 1888. t The paddle-fish is generally 

 supposed by fishermen to live on the slime and mud of the river 

 bottom, an idea confirmed at first sight by the general appearance 

 of the contents of the alimentary canal, which are commonly a dark 

 brownish semi-fluid mass resembling mud, but which, when placed 

 under a microscope, are seen to be made up largely of countless 

 myriads of Entomostraca of nearly every form known to occur in our 

 waters. Mixed with these in varying proportion, often, indeed, 

 predominating, are soft -bodied aquatic insect larvae, chiefly those 

 of day-flies, dragon-flies, and gnats (Chirononius), and a smaller 

 percentage of adult aquatic insects, amphipod crustaceans, leeches, 

 and water-worms {Naidoe), to which are added, in some cases, con- 

 siderable quantities of aquatic vegetation, largely algas, but includ- 

 ing likewise fragments of various aquatic plants. In the food of 

 eight specimens, obtained from Peoria, Pekin, and Henry, on the 

 Illinois, from the Ohio at Cairo, and from the Mississippi at Quincy, 

 in six years between 1877 and 1887, no fishes or mollusks were 

 found ; but insects and crustaceans — the latter mainly Entomostraca 

 — made by far the larger part of the food, the insects being taken 

 by all the specimens and in nearly twice the ratio of the crustaceans, 

 neuropterous larvae of daA-flies (Hexagenia) alone amounting to 47 

 per cent. As these are commonly creeping over the mud or swim- 

 ming near the bottom, it is likely that this fish is usually a bottom 

 feeder. One of our specimens contained nothing but insect food, 

 the ephemerid larvse above mentioned amounting to 85 per cent, of 



* Bull. 111. State Lab. Nat. Hist., Vol. I., p. 82. 

 t Ibid., Vol. II., pp. 464-467. 



