8 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
3. Hybognathus nuchalis Agassiz (? var. placita Girard). D. 
Ratlier rare about Denver. The specimens are all somewhat stout in form, the nose 
a little blunter than usual and rather less projecting beyond the mouth. Color very 
dark, the scales dark edged, and a dark lateral shade. Suborbitals very narrow. 
Eye 4 in head. 
These specimens may belong to the form called placiia, but the distinctions of 
varieties and species in this group are very unsatisfactor 5 ^ 
4. Notropis scylla (Cope). D. 
A few specimens from Denver, similar to others from Pueblo. 
5. Notropis gilberti Jordan and Meek. D. 
Very abundant at Denver. These specimens agree closely with the original types 
from the Des Moines River at Ottumwa, indicating that the species has a wide distri- 
bution over the western idains. The species has the lips somewhat thickened, and 
tliere is a little tlesliy projection at the corner of the mouth, not, however, amounting 
to a barbel. A little dusky shade on each side of the dorsal tin seems to be charac- 
teristic. Photogenis piptolepis Cope may be this species, but the description is not suf- 
ficiently full to permit identification. 
6. Notropis niegalops (Rafinesque). D. 
Not common ; apparently typical, scales before dorsal 23. 
7. Notropis lutrensis (Baird &, Girard). D. 
Not common; similar to Iowa specimens. Scales 33, 
8. Semotilus atromaculatus (Mitcliill). D. 
Common. Scales 60. Similar to Indiana examples. 
9. Rhinichthys dulcis (Girard). H., D., M. {BMnichthiis maxUlosus and trans^nontamis Coyie. Rliiri- 
idithya ocella Garman.) 
The Rhinichthys of the Rocky Mountain region strongly resembles the eastern 
B. cataracUe. It, however, differs constantly in the insertion of its dorsal, the front 
of the dorsal being midway between the base of the caudal and the nostril, while in 
B. eataractw the base of the dorsal is almost midway between the base of the caudal 
and the tip of the snout. B. dulcis is usually rather more slender than B. eataractw 
and has a sharper snout. It does not usually reach as large a size as the latter species. 
No difference in the- fins; scales or coloration seem to be iiermanent. 
The Bhiniclitliys of the upper Missouri, Arkansas, and Platte seems to be the 
same. That of the upper Rio Grande, called B. transmontanus by Professor Cope, is 
not evidently different. The species found in the Utah Basin {B. luteus Garman) has, 
as a rule, two or three more scales in a vertical row from dorsal to ventrals, twelve to 
fourteen below lateral line in luteus, ten or eleven in dulcis. But this character is 
variable and of rather doubtful value, and no other difference is apparent. 
10. Zygoiiectes floripinnis (Cope). D. 
One specimen taken, agreeing with Cope’s description. Outer teeth long, well 
separated. Scales 31-10. D. 10. Scales of back much punctulate with black. 
11. Etheostoma nigrum Rafinesque. D. 
Abundant, apparently like Iowa specimens. D. IX — 12. Scales 47. 
12. Salmo mykiss stomias Cope. M. 
Abundant in the Park Range and in mountain streams generally. 
