1£P) 



The length of the fish is contained one and two thirds times in 

 the length of the intestine ; the gill-rakers are few and rather short, 

 triangular, acute, and about one fifih the length of the correspond- 

 ing filaments. 



I examined carefully but three specimens of this species, derived 

 from two localities. These were y alike in the presence of great 

 quantities of mud, which amounted to about eighty-seven per cent, 

 of the contents of the intestine. The animal food was confined to 

 a trace of Cladocera. The vegetation amounted to thirteen per cent, 

 partly tissues of aquatic plants, with traces of fungi, bur chiefly 

 Algpe of various forms, including a little Oscillatoria. 



NOTEMIGONUS CHRYSOLEUCUS, Mitch. ShINER. 



This extremely abundant minnow, commonly called the shiner, 

 occurs in all waters throughout the State, from the largest rivers 

 to the smallest creeks, and from Lake Michigan to small stagnant 

 ponds. 



The intestine is shorter than in any of the preceding species, 

 although still rather long, the head and body being contained one 

 and one third times in its length. The gill-rakers are long, fine, 

 and numerous, about twenty in number on the anterior arch, and 

 fully one third the length of the corresponding filaments, making," 

 therefore, an effective apparatus for the separation of the Ento- 

 mostraca from the water. As this fish presents a peculiar combi- 

 nation of alimentary structures, and as its food was found unusu- 

 ally various, a larger number of specimens were studied than of 

 any of the species already discussed. 



Twenty-five fishes were dissected, from a great variety of situa- 

 tions in all parts of the State, and representing various dates Irom 

 May to September, inclusive. As the food differed widely according 

 to situation, that of specimens from certain localities being more 

 widely different than the food of different species has usually been 

 found, it will be best to mention the most conspicuous differences 

 depending upon situation. 



Specimens taken from the Pecatouica Eiver at Freeport, an extra- 

 ordinarily muddy stream, noted for the abundance of its mollusks, 

 had eaten no other food than univalve MoUusca, chiefiy Valvata 

 tricarinata and Flanorhis dejiectus. Another, from the Illinois Elver 

 at Pekin, had also eaten largely of mollusks, while three taken in 

 Otter Creek, in Jersey county, in almost stagnant reaches of the 

 stream, extremely muddy, and green with Algfe, had filled their in- 

 testines with mud, like Campostoma ; and still others from ponds 

 near Normal had eaten only Entomostraca, about equally Cladocera 

 and Copepoda. Another specimen from the Illinois Piver had taken 

 similar food, all Daphnias. One specimen from Xippersink Lake, 

 in the northern part of the State, was full of wild rice (Zizania). 

 Taking all the groups together, and considering the species as a 

 whole, besides the mud already mentioned, about fourteen per cent, 

 of the food consisted of mollusks, and only six per cent, of insects, 

 nearly all of which were of terrestrial species. Crustaceans 

 amounted to fifteen per cent , all Entomostraca. Vegetation stands 



