FISHES OF COLORADO 39 



Body moderately compressed, depth 4.2 to 4.7 in the length to the base of 

 the caudal; head 3.8 to 4. 25 in the length of the body; snout short and rather 

 blunt; eye prominent, its diameter about equal to the length of the snout, 1.25 

 to 1.5 in the interorbital space, 3.5 to 4 in the head; dorsal margin of the eye 

 almost on a level with the top of the head; mouth small and oblique; lower jaw 

 very slightly longer than the upper; angle of the mouth barely reaching the level 

 of the nostril; premaxillaries protractile; dorsal fin short but high, inserted behind 

 the ventrals, base of the first ray of the dorsal nearer the base of the caudal than 

 the tip of the snout; dorsal rays 7-g, usually 8; pectorals small, not reaching the 

 ventrals; ventrals barely if at all reaching the anal fin; anal short and rather 

 small; anal rays usually 8; caudal large, its width greater than the greatest depth 

 of the body; scales very small, circular, with apical, lateral and basal radii, 15 to 

 17, 78-88, 9 to 12; lateral line incomplete. 



General color above olive to brownish; a broad mid-dorsal stripe of dark 

 green to black; sides with two blackish stripes, one beginning at the tip of the 

 snout and crossing the head through the eye as a more or less imperfect bar, con- 

 tinuing from the posterior margin of the opercle along the region of the lateral line 

 as a heavy stripe and ending in a rather well-defined black caudal spot; the 

 second stripe lying about midway between the stripe along the lateral line and the 

 mid-dorsal one, narrower and less distinct, usually breaking up in the caudal 

 region; a row of small black dots, often entirely wanting, between the second 

 stripe and the mid-dorsal stripe; area between the first and second lateral stripes 

 silvery, with a yellowish cast; region below the lower lateral stripe pink or yellow- 

 ish, overlaid with silvery; fins, especially the ventrals and pectorals, yellowish, the 

 rays outlined with black; length 2. 5 inches or less. 



Males in the breeding season with the entire region below the first lateral 

 stripe and the under parts of the head a bright vermilion red; ventral and pectoral 

 fins bright yellow; dorsal fin yellow with a broad red spot at the base. 



Since the species Chrosomus dakotensis Evermann and Cox has been taken 

 at Valentine in western Nebraska,' it was first thought that the Colorado speci- 

 mens might be referable to that species. On examination it was found that the 

 12 specimens at hand did not warrant the recognition of such a species. C. dako- 

 tensis differs from C. erythrogaster in having 8 instead of 7 dorsal rays and in lacking 

 the distinct caudal spot (v/^^c Jordan and Evermann^). The tabulated comparison 

 of data from the Colorado specimens and those from Maine and Nebraska shows 

 no correlation of these characters (see Table II). 



It may be added that Forbes and Richardson^ give the dorsal fin rays of C. 

 erythrogaster as 7, rarely 6. The difference in the number of fin rays between the 

 Colorado specimens and the true C. erythrogaster from the eastern states seems 



■ Evermann and Cox, Rept. U.S. Com. Fisheries for i8g4, p. 395, 1896. 

 ' Bull. 47, U.S. Nat. Mus., pp. 209-210, 1896. 

 5 Ichthyology of Illinois, p. 113, 1909. 



