80 



FISHES OF ILLINOIS 



of the lower lip far in advance of the nostrils; lips evidently plicate, not 

 very thin, the halves of the lower one meeting at a rather wide angle; 

 interorbital space 2.4 to 2.7 in head; eye small, 5 to 6.4, usually more 

 than 5.5. Dorsal rays 25 to 30, usually nearer 30, anterior rays slender, 

 little elevated, scarcely more than half the length of base of fin. Scales 

 somewhat smaller and more closely imbricated than in the two pre- 

 ceding species, 7, 38 to 40, 6, usually 39 in longitudinal series; lateral 

 line complete, nearly straight. 



Fig. 20 



This species can be separated with readiness from both the pre- 

 ceding by its longer nose, more oblique mouth, and more posterior 

 nostrils; it is easily distinguished from the next when adult by its 

 larger size and by the differences in general proportions, and by the 

 shortness of the first dorsal rays. The young of these two species 

 can not be separated with any certainty. 



This carp-sucker belongs to the fauna of the Great Lake region 

 and is but rarely taken in the inland waters of Illinois, our adult 

 specimens numbering a very few from the Illinois river at Ottawa, 

 Henry, Havana, and Meredosia. It is too rare in our waters to be 

 commercially important. Its special habits are unknown. 



Genus ERIMYZON Jordan 

 (chub-suckers) 



Body oblong, more or less compressed; mouth subinferior; upper 

 lip protractile; lower lip plicate, infolded, forming an acute angle in 

 front; no anterior fontanelle; posterior fontanelle well developed; no 

 supraorbital bone; suborbital bones well developed, not much narrower 

 than the fleshy portion of the cheeks below; pharyngeal bones weak. 



