GENEB VI. AND [NTERIOB DISTRIBUTION 



(ill 



Aii examination of the general distribution of the species of 

 those sectional lists of Illinois fishes shows, as was to have been 

 expected, thai the distinctively northern Illinois fishes are chiefly 

 northern in their outside range, and that those of southern Illinois 

 are mainly southern. Thus, of the 14 especially northern Illinois 

 fishes, 11 are northerly in their general distribution and 1 is 

 southerly; while of the 9 distinctively southern Illinois species, 

 6 are southerly in their general range, 1 is western, and 1 is a 

 cave-fish local to Illinois. The species found in the northern 

 and central sections of the state and not in the southern are 

 varied in their distribution, 6 of them ranging northward from 

 Illinois, and 4 of them in all directions, while 1 has been thus far 

 found in Illinois only. The central and southern fishes, on the 

 other hand, comprise 7 southern species, 1 of northern and 8 of 

 general range, and 1 whose distribution is not recorded. Includ- 

 ing only species whose general area shows that their restricted 

 occurrence in Illinois is a feature of their geographical distribu- 

 tion at large, and excluding fishes special to the Great Lakes, 

 we have twenty-six species whose distribution in this state seems 

 limited by conditions connected with differences in latitude 

 merely — twelve of these species essentially northern and fourteen 

 of them southern. 



Especially Northern Species in 

 Illinois (16): 



Whitefish 



Lake herring 



Lake trout 



Long-nosed sucker 



Lake carp 



Notropis anogenns 



Great Lake catfish 



Mooneye 



Pike 



Muskallunge 



Menona top-minnow 



Brook stickleback 



Xine-spined stickleback 



Trout-perch 



Coitus ricei 



Uranidea kumlienii 



Especially Southern Species in 

 Illinois (14): 



Alligator-gar 

 Blue cat 



Ictalurus anguilla 

 Freckled stonecat 

 Harelipped sucker 

 Notropis pilsbyri 

 Viviparous top-minnow 

 Pigmy sunfish 

 Round sunfish 

 Lepomis symmetricus 

 Eupomotis heros 

 Hadropterus ouachitae 

 Elheostoma obeyense 

 E. squamiceps 



USE OF LOCALITY MAPS 



In the foregoing discussion of the sectional distribution of 

 Illinois fishes no account has been taken of differences in the 

 frequency of the occurrence of the species in the different sections 

 in which they have been found, a single occurrence in southern 

 Illinois, for example, counting for as much as fifty such occur- 



