64 UNIVERSITY OF COLORADO STUDIES 



broad frenum; a very small maxillary barbel on each side at the junction of the 

 upper and lower jaws; alimentary canal short; scales quite small; lateral line 

 complete; size rather small, length imder 5 inches. 



The species of this genus inhabit the cool, rapidly moving streams of northern 

 United States and southern Canada, ranging from coast to coast.' This genus 

 is represented in Colorado by the Dulcis Minnow, a species abundant in the 

 mountain streams east of the Continental Divide. 



Rhinichthys cataractae (Cuvier and Valenciennes) 

 Long-nosed Dace 



Gobio cataractae Cuvier and Valenciennes, Bist. Poiss., Vol. XVI, p. 315, 1842 (Niagara Falls). 



This species is represented in Colorado by the western subspecies Rhinichthys 

 cataractae dulcis (Girard), which may be separated from the true Rhinichthys 

 cataractae by the sharper snout and the position of the dorsal fin, the first ray of 

 the dorsal being nearer the base of the caudal fin than to the tip of the snout, 

 equidistant from the nostrU and the base of the caudal. The location of the base 

 of the first ray of the dorsal is subject to some variation (see Table IV). 



Rhinichthys cataractae dulcis (Girard) 

 Dulcis Minnow, Western Long-nosed Dace (Fig. 31) 



Argyreus dulcis Girard, Proc. Acad. Nat. Set. Phila., p. 185, 1856 (Sweetwater River, 

 Nebraska) . 



Rhinichthys maxillosus Cope — Cope and Yarrow, Wheeler Survey, Vol. V, p. 44, 187s (Twin 

 Lakes; Colorado Springs). 



Rhinichthys transmontaus Cope, Amer. Nat., p. 441, 1879 (Rio Grande in Colorado). 



Rhinichthys dulcis (Girard)— Jordan, Bull. U.S. Pish Com., Vol. IX, pp. 8, 11, 16, 22, 1889 

 (Denver; South Platte at Hartsels Springs; Bear Creek above Morrison; Pueblo; Lake Creek 

 at Granite; Arkansas at Leadville; Twin Lakes; Alamosa; Del Norte; Rio Conejos fifteen 

 miles south of Alamosa). 



Rhinichthys cataractae dulcis (Girard) — ^Juday, Univ. Colo. Studies, Vol. II, p. 113, 1903 

 (Boulder); JtroAY, Bull. U.S. Fish Com., Vol. XXVI, p. 162, 1906 (Twin Lakes). 



Body elongate, slightly compressed; depth 4.5 to 5.5 in the length to the 

 base of the caudal fin; head depressed, long and pointed, its length 3.5 to 4 in 

 the length; dorsal profile of the head sloping anteriorly, ventral profile almost 

 straight; snout produced, overhanging the mouth, length of the snout 2.6 to 3 

 in the length of the head; eye prominent, situated near the center of the side of 

 the head, its diameter about 2 in the snout, 1.8 to 2 in the interorbital distance, 

 and 5 in the head; nostril large, just in front of and somewhat dorsal to the eye; 

 mouth ventral, sucker-like; lips large and fleshy, the upper recurved around the 

 angle of the mouth; a small but distinct barbel in a slight depression at the angle 

 of the mouth, which is about level with the posterior margin of the nostril; pre- 



■ Snyder, Bull. U.S. Fish Com.. Vol. XXVII, p. 178, 1907, reports R. dulcis (Girard) from Corvallis. 

 Oreson. 



