Jordan and Ever maun. Fishes of North America. 185 



Snout 2J iu head ;* breast naked ; caudal peduncle much slenderer than 

 in X. cypho, dorsal fin lower; caudal large. Coloration plain olivaceous. 

 Known from a single specimen, 7 inches long, taken in Uncompahgre 

 River (Colorado basin) ; possibly a variation of X. cypho, but quite unlike 

 all known examples of the latter. 



Xiiraiiclirn inx'oiiipitligre, JORDAN & EvERMANN, Bull. U. S. Fish Com., 1889, 26, published 1891, 

 Uncompahgre River, Delta, Colorado. 



95. ERIMYZON, Jordan. 

 (CHUB SUCKERS.) 



Morostoma, AGASSIZ, Am. Jour. Sci. Arts, 1854, 200, (oblongus), not of Rafinesque. 

 /."/ K////70H, JORDAN, Bull. Buffalo Soc. Nat. Hist., 1876, 95, (oblont/us). 



Body oblong, compressed. Head moderate. Mouth moderate, some- 

 what inferior; the upper lip well developed, freely protractile; the lower 

 moderate, infolded, ^-shaped in outline, plicate, with 12 to 20 folds on 

 each side. Lower jaw without cartilaginous sheath, rather stronger than 

 usual, and oblique when the mouth is closed. Eye moderate. Suborbital 

 bones well developed, not much narrower than the fleshy portion of the 

 cheek below them ; opercular bones moderately developed, not rugose. 

 Fontanelle rather large. Gill rakers rather long. Pharyngeal bones 

 weak; the teeth quite small, slender, and weak, rapidly diminishing in 

 length upward, each tooth narrowly compressed, with a cusp on the 

 inner margin of the cutting surface. Scales rather large, more or less 

 crowded forward. Lateral line entirely wanting at all ages. Dorsal fin 

 rather short and high, rays usually 11 or 12. Pectoral fins moderate. 

 Anal fin high and short, more or less emarginate or bilobed in adult males. 

 Caudal fin moderately forked or merely lunate, its 2 lobes about equal. 

 Air bladder with 2 chambers. One species ; widely distributed, (tpi-, an 

 intensive particle; ,uvdu, to suck.) 



802. ERIMYZON SCCETTA, (Lacep&de). 



(CREEK FISH:; CHUB SUCKER.) 



Body oblong, compressed, becoming gibbous with age, the antedorsal 

 region more or less elevated in the adults, the depth about 3 in length, rang- 

 ing from 2i in adults to 4 in young. Head stout, short, about 4 in length, 

 the interorbital space wide. Eye rather large, 4i head. Scales usually 

 closely imbricated and more or less crowded forward, but often showing 

 various irregularities in arrangement, the usual number 36-15. D. usu- 

 ally 12 ; A. 7 ; V. 9. Coloration varying with age ; usually showing pale 

 streaks along the rows of scales; young with a broad black lateral band, 

 bordered above by paler ; in some specimens from clear water this baud 

 is of a jet black color and very distinct; in others it is duller; later this 

 baud becomes broken into a series of blotches, which often assume the 

 form of broad transverse bars ; in adult specimens these bars disappear, 

 and the color is nearly uniform brown, dusky above, paler below, every- 

 where with a coppery or brassy, never silvery, luster; the fins dusky or 

 smoky brown, often reddish tinged. Sexual difference strong ; males 

 in spring usually with 3 large tubercles on each side of the snout, and 



