26 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Brothers have a trout hatchery further up the river at Los Pinos. Like the Animas, 
this is an excellent trout stream. 
20. Ignacio Lal:es. — Near Los Pinos River are the San Ignacio Lakes, one of 60 acres, 
one of 40 acres, at 8,000 feet elevation. They are fed by springs and have no outlet. 
They have no fishes but are said to be ‘‘ full of dog fish {Amblystoma ?) which devour 
the young trout which have been several times placed in the lakes.” We were unable 
to verify this statement which was made by a citizen of Durango. 
21. Bio de las Piedras, said to be the best trout stream in the San Juan basin, is 
similar to Los Pinos, but smaller. 
22. Rio Navajo, which flows into the San Juan near Juanita, is also similar; a 
clear stream with gravelly bottom and wooded banks. 
23. Bio San Juan, which receives the waters of all these, is, when crossed by the 
railroad at Arboles, about the size of Los Pinos at Ignacio. Its water is warm and 
not quite clear; the bottom of gravel and stones. About Pagosa Springs, above Ar- 
boles, it is a trout stream. Below Arboles it becomes very yellow, and at last it 
bears a volume of very muddy water into the Colorado. 
FISHES OF THE UPPER COLORADO BASIN. 
1. Catostomus latipinuis (Baird & Girard). Flannel-mouth Sucker. 
Very common in the Grand River at Glen wood Springs, in the Gunnison and 
Uucompahgre at Delta, and in Green River. It reaches a length of to 2 feet and a 
weight of 3 to 5 pounds. Dorsal rays usually 11, sometimes 12 or even 13. Caudal 
peduncle slender, and the fins all high ; these characters especially marked in old 
males. Large specimens, in life blackish, olive above, abruptly paler below ; sides 
bright creamy orange, deepest on the tail ; snout and cheeks pale orange ; belly pure 
white ; lower fins all more or less orange ; upper fins dusky olive, tipped with orange; 
pectoral dusky, orange above, creamy below; axil blackish; lips very thick and large. 
Female specimens have the same color, the only difference being that the male has the 
anal and lower lobe of caudal tuberculate. Stomach full of confervm and other vege- 
tation. 
Catostomus discobolus Cope, from Green River in Wyoming, is probably based on 
the young of Catostomus lati/pinnis. The fishes from Idaho, formerly recorded by me 
as Catostomus discoboltis, are probably different. 
2. Xyrauchen cypho (Lockiugton). Razor-hack Sucker ; Hump-hack Sucker. (Plate IV, Fig. 11.) 
This remarkable fish is very abundant in the river channels of the Colorado Basin. 
It reaches a weight of 8 to 10 pounds, and is largely used for food. Specimens were 
taken by us at Delta, both in the Gunnison and the Uncompahgre, and in Green River. . 
Specimens of 8 inches have the depth equal to length of head, 3J in length. 
Scales 13-72, 73, or 74-13; D., 14. First dorsal ray, 1^- in head; base of the fin, li. 
Least depth of caudal peduncle, 3 in head ; 1^ in distance from last anal to first cau- 
dal ray. Nuchal crest much elevated, commencing by a prominence close to the nape, 
and with no scales before it ; nuchal crest nearly or quite naked on the median lijie. 
3. Xyrauchen uncompahgre .Iordan & Everinann, sp. uov. (Plate V, Fig. 12.) 
A single young specimen of Xyrauchen, about 7 inches long, taken in the Uncom- 
pahgre River, close to the railway station at Delta, difi'ers much from the others, and 
probably represents a distinct species of tlni same singular genus. 
