GENUS CHASMISTES JORDAN 



Head large, broad and flattish above, the sides vertical; eye 

 small, high up, and rather posterior; mouth very large, terminal, 

 the lower jaw in the closed mouth being very oblique; lower 

 jaw long and strong, more than half length of head, its tip, 

 when the mouth is closed, about on a level with the eye; upper 

 jaw very protractile; upper lip thin and nearly smooth; snout 

 usually elevated above rest of head ; the premaxillary spines gene- 

 rally forming a conspicuous nose; lower lip moderate, consisting 

 of a broad flap on each side of the mandible, reduced to a nar- 

 row rim in front, the surface of the lip nearly smooth, without 

 papillae; nostrils large; fontanelle well developed; gillrakers simple, 

 fringe-like; air-bladder in 2 parts. Species of rather large size, 

 inhabiting the Great Salt Lake Basin and the Klamath Lakes of 

 southern Oregon. 



Six species are recognized, only 4 of which seem to be of 

 any commercial importance. 



a. Scales moderate, 60 to 65 in the lateral line. 



b. Scales 9-63-8; dorsal usually 11; nose prominent; Horns, 54 

 aa. Scales small, 75 to 85 in the lateral line. 



r. Snout prominent, premaxillary spines strongly protruding, form- 

 ing a prominently projecting snout: sioniias, 55 



cc. Snout not prominent, premaxillary spines not forming a pro- 

 minent hump. 



d. Scales 12-75- 1 1 ; brevirostris. ss 



dd. Scales 13-80-12 ; copei, 56 



June Sucker of Utah Lake 



C/tdswis/cs Horns Jordan 

 Known only from Utah Lake, where it is exceedingly abundant, 



54 



