GENERAL AND INTERIOR DISTRIBUTION Cxiii 



their ratios running from 70 per cent, for rubrifrons to 41 per 

 cent, for cornutus. 



The species of our list which have from 50 to 100 per cent, of 

 their representatives in creeks, as illustrated by our collections, 

 include three sunfishes (the green sunfish, the round sunfish, and 

 the long-eared sunfish), three suckers (the common sucker, the 

 chub-sucker, and the striped sucker), four darters, ten minnows, 

 and the brindled stonecat. 



The larger species found most abundantly in lakes, ponds, 

 and other stagnant waters were the common bullhead, the 

 buffaloes, the yellow perch, the white bass, the yellow bass, the 

 large-mouthed black bass, and five sunfishes (both crappies, the 

 warmouth, the pumpkinseed, and the bluegill) ; and the smaller 

 kinds were the smallest of our fishes (Microperca punctulata), 

 another darter (Boleichthys fusiformis) , two minnows (Notropis 

 cayuga and N. heterodon), the mud-minnow, and a killifish 

 (Fundulus dispar). 



Turning next to the 62 species for which our data of pref- 

 erence or avoidance of a muddy bottom are available, we find 

 7 species whose ratios of frequency of occurrence in such situa- 

 tions range from 43 to 88 per cent., and which may consequently 

 be called limophagous fishes. These are the warmouth sunfish, 

 the black and the yellow bullheads, the pirate-perch, a single 

 darter (Boleosoma camurum), and two minnows, the golden 

 shiner and the common shiner (Notropis cornutus). 



It is interesting to find, by an examination of our maps, 

 that all these 7 species are freely distributed over the lower 

 Illinoisan glaciation of the southern part of the state, where, as 

 we have already shown, only fishes indifferent to a peculiarly 

 persistent turbidity of the water are likely to occur. 



By selecting from this same list of 62 species those with the 

 lowest ratios of frequency over a muddy bottom, we get 13 species 

 (with ratios of 4 to 10 per cent.) which evidently avoid such 

 situations; and these, again, are without exception so distributed 

 that the area of the lower Illinoisan glaciation is almost never 

 entered by them. These are one of the native carp (velifer), a 

 species of red-horse (aureolum), the small-mouthed black bass, 

 two darters (Hadropterus phoxocephalus and Etheostoma coeru- 

 leum), five minnows (Campostoma anomalum, Notropis heterodon, 

 Ericymba buccata, Hybopsis kentuckiensis , and Notropis blennius), 

 two stonecats, and the little brook silverside (Labidesthes) . 



—8 P 



