FISHES OF COLORADO 37 



North America. A single species, quite abundant in the plains streams of the 

 eastern part of the state, is known from Colorado. 



Campostoma anomalum (Rafinesque) 

 Stone-roller, Greased Chub (Figs. 13, 14 and 16) 



Rulilus anomalus Rafinesque, Ichthyologia Ohiensis, p. 52, 1820 (Licking River, Kentucky). 



Campostoma anomalum (Rafinesque) — Jordan, Bull. U.S. Fish Com., VoL IX, p. 16, 1889 

 (Arkansas River, Canyon City); Juday, Univ. Colo. Studies, Vol. II, p. 113, 1903 (Longmont and 

 Boulder); Juday, Bull. U.S. Fish Com. for igo4, p. 226, igos (Boulder; Longmont). 



Campostoma aikenii Cope — Cope and Yarrow, Wheeler Survey, Vol. V, p. 672, 1875 (Pueblo). 



Body rather elongate, fusiform, but slightly compressed; depth 4 (old males) 

 to S (young and medium individuals) in the length to the base of the caudal; 

 head moderately large and pointed, somewhat conical as a whole, its length 3.75 

 to almost 4. s (young) in the length; snout rather long, blunt, slightly overhanging 

 the mouth; eye fairly small, larger in the young, its diameter 4.7 (young) to 6. 5 

 (old males) in the length of the head, 2 to 2. 25 in the interorbital distance; 1.5 to 

 2.7 in the snout; nostrils prominent, situated about the diameter of the eye in 

 front of the eye and dorsal to the center of the eye; mouth ventral and slightly 

 oblique, sucker-like; lips thick, especially the upper, a fleshy lobe at the angle 

 of the mouth on each side, formed by the fusion of the two lips; angle of the 

 mouth reaching the level of the nostrils; premaxillaries protractile; dorsal fin 

 rather short, its length slightly less than that of its longest ray, inserted near the 

 middle of the body, on a level with or just in front of the ventrals, base of the first 

 ray of the dorsal nearer to the tip of the snout than to the base of the caudal in 

 adults, in small individuals nearer the base of the caudal; dorsal rays 8; pectorals 

 short, not reaching the ventrals; ventrals not reaching the anal opening; anal 

 smaller than the dorsal; anal rays 7; scales rather large, 7 to 9, 46-58, 7 or 8; 

 lateral line complete, quite decurved before the dorsal. 



Dark above, almost black in the mid-dorsal region, with a metallic luster; 

 sides brassy yellow to silvery, mottled irregularly with dusky; below the lateral 

 line silvery white, ventral parts immaculate; top of the head dark green; sides of 

 the head brassy to yellowish ; a faint dusky caudal spot ; fins hyaline or yellowish, 

 dorsal usually somewhat dusky; length 6 to 10 inches. 



Breeding and old males with the body just back of the head and in front 

 of the dorsal distinctly elevated; body above the lateral line with pearl organs 

 (some below the lateral line in the caudal region) ; top of the head with conical 

 homy tubercles. General color of breeding males much the same as that of other 

 individuals, all markings and colors, however, more prominent; dorsal fin with a 

 series of heavy black A-shaped marks, one on each ray with the point toward the 

 margin of the fin, the entire series forming a deeply serrate band crossing the middle 

 of the dorsal, area below this black band yellowish or often bright orange-red; anal 

 fin often marked much like the dorsal; other fins more or less yellowish. 



