162 FISHES OF ILLINOIS 



RHINICHTHYS ATRONASUS (Mitchill) 



BLACK-NOSED DACE 



Mitchill, 1815, Trans. Lit. and Phil. Soc. N. Y., I, 460 (Cyprinus). 

 G., VII, 191; J. & G., 208; M. V., 63; J. & E., I, 307; N., 45, also 46 (lunatus and 

 meleagris); J., 63 (obtusus and meleagris); F., 75 (part); K, 18. 



Length 2 l /i inches; body moderately elongate, very little compressed; 

 depth 4.5 to 5 in length; caudal peduncle rather short and deep, less than 



head, its depth 1.7 to 2.1 in its length. Color 

 dusky to blackish above, the back and sides 

 variously mottled with darker; a black band 

 along sides, through eye to end of snout, be- 

 low which is a paler streak; belly silvery; a 

 distinct black blotch at base of dorsal be- 

 hind; dorsal otherwise and all other fins plain; 

 spring males with the lower fins and often 

 FlG 4! almost entire body more or less blood-red, 



this color becoming obsolescent by midsum- 

 mer. Head pyramidal, subquadrate in transverse section, being a little 

 wider than deep; length of head 3.6 to 4.2 in head and body, its width 1.7 

 to 2 in its length; interorbital space fiat, 2.8 to 3.1; eye small, 4.3 to 4.9; nose 

 long and projecting, but not decurved, both nostrils lying well in upper half 

 of head; length of nose 2.7 to 3 in head; mouth rather small, subterminal, 

 slightly oblique, tip of upper lip as high as lower margin of orbit; maxillary 

 shorter than in the last species, 3.3 to 4 in head, usually over 3.6, reaching 

 scarcely past anterior nostril; a minute maxillary barbel; lower jaw included; 

 isthmus twice width of orbit. Teeth 2, 4-4, 2; peritoneum silvery except 

 high up, where it is dusky. Dorsal fin with 8 rays, set distinctly behind 

 ventrals, 15 to 20 per cent, farther from muzzle than base of caudal; longest 

 dorsal ray 1.3 to 1.4 in head; anal rays 7; pectorals about % to ventrals, 

 1.3 to 1.5 in head; ventrals past base of anal in adult males. Scales 9 to 

 11, 62-71,8 to 10; lateral line complete, little decurved. 



This species, widely distributed like the preceding, extends 

 from New Brunswick and the rivers of northeastern Quebec 

 through the Hudson and the Great Lakes to the James and the 

 Roanoke, to the Dakotas in the northwest, and through the Ohio 

 basin to Iowa and northern Alabama. We have found it in only 

 six Illinois collections, all but one in the clear swift brooks of the 

 northern part of the state. The northern Illinois localities re- 

 ported are Oregon, Ogle county, Bailey's creek and other streams 

 of La Salle county, Big Rock creek and Little Rock creek, near 

 Piano, in Kendall county, the lakes about Henry, in Marshall 

 county, and Farm creek, near Peoria. We have also two speci- 

 mens from Big creek, near Anna, in Union county, in extreme 

 southern Illinois. 



