164 UNIVERSITY OF COLORADO STUDIES 
Famity Catostomide (The Suckers) 
Amyzon Cope, is represented in the Miocene of Florissant (A. commune Cope, A. 
fusiforme Cope, A. mentale Cope, A. pandatum Cope). 
The living Rocky Mountain species are: 
Dorsal fin elongate, with 26 or 27 rays (Boulder County, Juday; Milk R. and Poplar R. in 
Montana, Henshall; Rio Grande) . . . Carpiodes i (Raf.) (Quillback). 
Dorsal fin with not over 18 rays . . PUL, 
1. With a sharp-edged hump on the ce not egiendiee parwat | to the nape; D 12, 
A 7; scales 16-81-13. (Known from a single specimen, 7 inches long, from the 
Uncompahgre River at Delta, Colo.) Xyrauchen uncompahgre Jordan and Evermann 
(X. cypho Lock.), from the basin of the Colorado and Gila Rivers, has a higher 
hump, which usually begins at the nape.) 
Normally formed, nothumped . . . RL, Sa) SA Rs 
a. Scales an lateral Winelecs than ee weet cy Se ef) wre” oh lay tee ee nee 
Scalesiin lateral linejoveriOor tio ic eames way ile. ess ah Seer 
Fic. 1.—Catostomus commersonii. 
3. Dorsal rays usually 12; dusky above, with usually a black blotch behind the dorsal 
fin; each scale along the sides with a small, more or less distinct blackish spot at its 
base, these spots forming interrupted longitudinal lines along the rows of scales; size 
up to r8 inches long. (Yellowstone R.) 
Minytrema melanops (Raf.) (Spotted Sucker). 
Dorsal rays usually 13; olivaceous, sides silvery, lower fins in adult red or orange (Poplar 
R., Mont., Henshall) . . . . . . . Moxostoma aureolum (Le Sueur). 
4. Scales in lateral line less than 80; Gpaeaets between parietal bones present, widely 
open.) ': ew BoB ede eae St ny 
Scales in taker ae 80. or more e 
5. Dorsal fin long, of 15 rays; head ae ‘Swen oe ae Post Great, anaes Hen- 
shall) POPE! lpm iG. LLP E . . .  Catostomus macrocheilus Girard. 
Dorsal fin with rr to13 rays. . . RP ey Bok 
6. Upper lip narrow, with usually but 3 to 5 rows i parihe, jue in var. suckliz (Girard) 
with 4 to 6; species of Atlantic slope (Boulder Creek, common; Milk R. and Poplar 
R., Montana; Twin Lakes, Colo.; Arkansas R. at Pueblo, Colo.) 
Catostomus commersonti (Lacép.)- 
