1 XXX VI 



FISHES OF ILLINOIS 



Interior Distribution of Illinois Fishes by River Systems 

 Species and Number of Collections of each — concluded 



THE ILLINOS BASIX AND THE OTHER DISTRICTS COMPARED 



The key to the distribution of IlHnois fishes within the state is the 

 species Hst of the IlHnois basin. Covering fully one half the area of Illi- 

 nois, and extending in a broad belt diagonally northeast and south- 

 west 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 ]\Iississippi 

 on the other, and it is to be expected that its fish population will be 

 highly typical of Illinois as a whole. It includes, in fact, more than 

 four fifths of the species on our Illinois list, and the special features 



