GENERAL AND INTERIOR DISTRIBUTION 



XCl 



Inteeior Distribution of Illinois Fishes by River Systems 

 Species and Number of Collections of each — concluded 



THE ILLINOIS BASIN AND THE OTHER DISTRICTS COMPARED 



The key to the distribution of Illinois fishes within the state 

 is the species list of the Ilhnois basin. Covering fully one half 

 the area of Ilhnois, and extending in a broad belt diagonally 

 northeast and southwest across its northern two thirds, this 

 basin contains nearly every variety of stream, lake, pond, and 

 marsh to be found between the Great Lakes on the one hand 

 and the giant flood of the Mississippi on the other, and it is to 

 be expected that its fish population will be highly typical of 



