GENERAL AND INTERIOR DISTRIBUTION XCV 



SOUTHERN (10) : MAIN MISSISSIPPI (1) : 



Harelipped sucker White sturgeon 



Pigmy sunfish 



Eound sunfish subterranean (1): 



Eupomotis heros Chologaster papilliferus 



Hadropterus ouachitce 



H. evides rare in Illinois (2) : 



Crystallaria asprella Brook lamprey 



Etheostoma obeyense Long-nosed dace 



E. squaniiceps 



Brindled stonecat 



GREAT LAKES (5): 



Whitefish 

 Lake herring 

 Lake trout 

 Cottus ricei 

 Uranidea kumlienii 



As the Illinois basin contains 128 of the 150 species taken 

 by us in the state, it is evident that the other and smaller basins 

 must differ from this negatively rather than positively. Being 

 not only much smaller, but also much less complex than the 

 Illinois district, and offering less variety of situations for fishes 

 as homes and places of resort, they may lack niany species which 

 find a fit environment somewhere in the Illinois or its dependent 

 waters, but can contain relatively few not found there as well. 



Regarded from this standpoint, the Michigan district is 

 farthest removed from the Illinois ichthyologically, and of its 

 'fifty-seven species nine (16 per cent.) are wanting in the Illinois 

 basin. The Cairo district differs much less, eight of its one 

 hundred and one fishes being without representation in our 

 collections from the Illinois system. Next follows the Wabash 

 basin in Illinois, with ninety-five species and a difference from 

 the Ilhnois basin of 6.1 per cent.; the Galena district, with 

 forty-four species and a difference of 4.6 per cent.; the Saline 

 district, with fifty-five species, and a difference of 3.8 per cent.; 

 and the Mississippi and its marginal area, with ninety-seven 

 species, 3.2 per cent, of which are wanting to the Illinois streams 

 and lakes. The Kaskaskia and the Big Muddy, on the other 

 hand, which are scarcely more than extensions of the Ilhnois 

 district downward to the southern end of the state, contain 

 virtually no fishes not in the main district, the Kaskaskia but 

 one out of sixty-nine (1.4 per cent.), and the Big Muddy none 

 out of fortj^-two species. The Rock River district differs from 

 the Illinois by onl}^ three species out of ninety-two (3.2 per 

 cent.). These data are presented more compactly in the table 

 following. 



