FISHES OF COLORADO 



67 



to the fishes of that type and our single specimen of this kind regarded as a varia- 

 tion. In this case the name of the subspecies found in Colorado should stand 

 R. cataractae maxillosus (Cope). 



TABLE V 



Scale Formulae of io Random Specimens 

 Creede, Rio Grande 

 12-67-12 

 1 2-68-1 1 

 12-69-H 

 1 2-70-1 1 

 12-70-12 

 1 3-66- 1 1 

 14-61-10 

 14-68-11 

 14-69-12 

 14-71-12 



Scale Formulae of 10 Random Specimens 

 Boulder Creek, Boulder 

 11-62-11 

 11-59-11 

 12-58- 9 

 12-64-10 

 12-66-10 

 12-67-12 

 13-65-11 

 I 3-63- I I 

 13-S9-" 

 14-60-12 



Scales above lateral line . . . 

 No. of specimens, Creede. . 

 No. of specimens, Boulder . 



II 



12 



13 



69 70 71 



Scales below lateral line 9 10 



No. of specimens, Creede i 



No. of specimens, Boulder i 2 



Scales in the lateral line 58 59 60 61 62 63 64 65 66 67 



No. of specimens, Creede i i i 



No. of specimens, Boulder i 2 i.. i i i i i i 



The Dulcis Minnow, although of the carnivorous group of Csrprinids, feeds 

 to a considerable extent on plant material. The stomach contents of 20 speci- 

 mens from Boulder Creek near Boulder showed that the algae and brown diato- 

 maceous slime so generaUy eaten by herbivorous Cyprinids are important elements 

 in the food of this miimow, forming about two-thirds of the material. Small 

 crustaceans, insect larvae, small snails and water-logged material comprised the 

 remaining third. It is known that the Dulcis Minnow also eats the spawn of 

 the trout. On the other hand, the Dulcis Minnows are eaten by the trout, 

 making the presence of these minnows in the mountain streams of value. This 

 species is also used as live bait. Rhinichthys cataractae dulcis spawns in the early 

 spring. 



Colorado specimens. — University Museum: Boulder Creek, Boulder, October, 1903 (56 

 specimens, 65-80 mm.), C. Juday and J. Henderson, No. 11; Twin Lakes, August, 1903 (3 speci- 

 mens, 100-105 mm), C. Juday, No. 34; West Plum Creek near Castle Rock, June 8, 1912 (18 

 specimens, 35-70 mm), A. G. Vestal and M. M. Ellis, No. 379; Cherry Creek near Frankton, 

 June 9, 1912 (5 specimens, 65-85 mm), A. G. Vestal and M. M. Ellis, No. 380; Boulder Creek six 

 miles east of Boulder. July 25, 191 2 (138 specimens, 35-85 mm.),M. M. Ellis, No. 381; Rio Grande, 

 Alamosa, July 27, igi2 (2 specimens, 50-55 mm.), M. M. Ellis, No. 382; Rio Grande, Creede, 



