160 FISHES OF ILLINOIS 



A few case-worms {Phyrganeidce) occurring in some similar situa- 

 tions were the only other important element of the food, of which 

 insects made practically 98 per cent. Its small inferior mouth, 

 provided with fleshy lips something like those of a sucker, enables 

 this minnow to collect readily its peculiar food, in respect to 

 which, as well as in its favorite haunts, it bears a considerable 

 resemblance to the darters. In the aquarium it rests, like a 

 darter, upon the sand, supported by its pectoral fins, the head 

 moving gently up and down with the opening and closing of the 

 gills. 



Females greatly distended with eggs were taken by us in late 

 May and early June. Spring males are profusely but rather mi- 

 nutely tuberculate on the top of the head, on the opercles, and on 

 the back and upper part of the sides to the posterior end of the dor- 

 sal fin. 



Genus RHINICHTHYS Agassiz 



Body elongate, little compressed; mouth small, subinferior; upper 

 jaw not protractile, the upper mesially continuous with the skin of the 

 forehead; a small barbel at tip of maxillary; teeth 1 or 2, 4-4, 1 or 2, 

 hooked and without grinding surface; intestine short; peritoneum dusky; 

 dorsal rays 7 to 9; anal 6 or 7 ; scales 60 to 70; lateral line continuous. 

 Size small, 3 to 5 inches. Species few, 2 in Illinois. Active fishes, 

 inhabiting mountain springs of the east and west and the swifter and 

 cooler brooks of the central United States. 



Key to the Species of RHINICHTHYS found in Illinois 



a. Snout long and prominent, projecting far beyond the inferior mouth, less 

 than 2^ in head and inore than twice length of eye in adults. . .cataractae. 



aa. Snout moderate, projecting little beyond the mouth (which is subterminal) , 



more than 2 J in head, and not over 1^ times length of eye in adults 



atronasus. 



RHINICHTHYS CATARACT.E (Cuvier & Valenciennes) 



(long-nosed dace) 



Cuvier & Valenciennes, 1842, XVI, 315 (Gobio). 



G., VII, 176 (Ceratichthys) and 189 (Rhinichthys marmoratus and R. nasutus); 

 J. &G., 207; M. V., 63; J. & E., I, 306; N., 45 (nasutus and maxillosus) ; J., 62; 

 F., 75 (atronasus, part). 



Distinguished from the next species by its longer snout, longer and 

 much projecting upper jaw, more elongate body, and less coarsely mottled 

 coloration. Length 2h inches; depth 4.8 to 5.2 in length; caudal peduncle 



