FISHES OF COLORADO 29 



above, its length 4. 25 to 4. 75 in the length of the body; dorsal profile sloping 

 slightly, ventral profile almost straight; snout broad and rather long, overhanging 

 the mouth by almost the diameter of the eye; eye small, 5 to 7 in the head, sit- 

 uated in the posterior half of the head; interorbital distance 2.5 to 2.75 in the 

 head; mouth large, ventral; both jaws with well-developed cutting edges; upper 

 lip large, forming a fleshy hood over the mouth opening, median indentation of 

 the lower lip not reaching the margin of the lower jaw but separated from it by 

 4 or more rows of papillae; dorsal fin moderately high, its longest ray exceeding 

 in length the base of the fin, of 10 or 11 rays, inserted nearer the tip of the snout 

 than to the base of the caudal; pectorals not reaching the ventrals; ventrals not 

 reaching the anal opening; anal rather small, of 7 or 8 rays; scales rather uniform 

 in size, not much crowded anteriorly, scales in the lateral line 80 to 92, usually 

 about 85. 



General color dark greenish brown to blackish ; mid-dorsal region and to some 

 extent the sides, mottled with dusky; dorsal color extending well down on the 

 sides of the body; lower portion of the sides yellowish to bright orange, orange- 

 red in breeding males; under parts white to yellowish; a rather well-defined 

 dark-red band along the lateral line; fins hyaline or yellowish, rays dusky; anal 

 often reddish. 



This species does not reach the large size attained by some of the species of 

 Calostomus, average adults being from 9 to 12 inches in length. 



The Rio Grande Sucker is a species of the Rio Grande drainage ranging from 

 the San Luis Valley in Colorado south into Chihuahua. It is quite abundant 

 throughout its range. 



The stomachs and intestines of twenty specimens of this species from Alamosa, 

 July 27, 191 2, were packed with sUme, algae and mud. So much of the green 

 algae was present that the alcohol in which the Alamosa collections were placed 

 was colored green by the extracted chlorophyO. 



Colorado specimens. — University Museum: Rio Grande, Alamosa, July 27, igi2 (309 speci- 

 mens, 5o-20o mm.), M. M. Ellis, No. 322. 



Pantosteus delphinus (Cope) 

 Blue-headed Sucker, Western CmsEL-MOUXHED Sucker (Fig. 9) 



Minomus delphinus Cope, Hayien's Survey of Wyoming for 1870, p. 435, 1872 (probably 

 Henry Fork of Green River, Wyoming). 



Pantosteus delphinus (Cope) — Jordan, Bull. U.S. Fish Com., Vol. IX, p. 27, 1889 (Eagle 

 River; Gunnison at Delta; Uncompahgre; Rio las Animas Perdidas; Rio Florida). 



Pantosteus virescens Cope — Cope and Yarrow, Wheekr 's Survey, Vol. V, p. 675, 187s (wrongly 

 ascribed to Arkansas at Pueblo, corrected by Jordan and Everuann, Bull. 47, U.S. Nat. Mas., 

 p. 171, 1896). 



Body elongate, somewhat compressed in the caudal half; depth 5 to 5.5 in 

 the length to the base of the caudal; head rather large, its length about 4. 5 in the 



