162 FISHES OF ILLINOIS 



RHINICHTHYS ATRONASUS (Mitchill) 

 (black-nosed dace) 



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

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

 meleagris); J , 63 (obtusus and meleagris); F., 7 5 (part); L., IS. 



Length 2f 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 ; 

 |. ,,. 4i spring males with the lower fins and often 



almost entire body more or less blood-red, 

 this color becoming obsolescent by midsummer. Head pyramidal, sub- 

 quadrate 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 ; inter- 

 orbital space flat, 2 . 8 to 3 . 1 ; eye small, 4.3 to 4 . 9 ; nose long and project- 

 ing, 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, slightlv 

 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 . S in head ; ventrals past base of anal in adult 

 males. Scales 9 to 1 1 , 62-7 1 , 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 1 minks 

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

 reported 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 e< lunty, 

 and Farm creek, near Peoria. We have also two specimens from 

 Big creek, near Anna, in Union county, in extreme southern 

 Illinois. 



