30. catostomid.t: — chasmistes. 131 



series. Depth 4i-5 iu length ; head 4-4J. Eye rather small, 4J to 5 



in head. Color olivaceous; sides with brassy lustre ; belly white ; back 



brown, with several dark cross-blotches, irregularly arranged, these 



becoming obsolete iu old individuals; lower tius dull red, with some 



dusky shading; young considerably variegated, the sides spotted. Size 



large; maximum length about 2 feet. jSTcw York to Alabama and 



Kansas ; abundant. Ascends streams to spawn early in spring. 



(Le Sueur, Journ. Acad. Nat. 8ci. Pliila. 1818, 102: IIiilomy:::on nigricans Agassiz, 

 Amer. Journ. Soi. Arts, 1855, 205 ; Giiuther, vii, 17 ; Jordan, 1. c. 1G2.) 



65.— CBIASilIB§TE§ Jordan. 



(Jordan, Bull. Haydeu's Geol. Sur\-. Terr, iv, Xo. 2, 417, l>7d : typo Chasmistcs Horns 

 Jor.) 



Head disproportionally large, forming more than one-fourth of length, 

 broad and flatfish above ; sides of head vertical, slightly directed in- 

 wards, the breadth through the cheeks less than the breadth above the 

 eyes. Eyes small, high up, rather posterior. IMouth extremely large, 

 terminal, the lower jaw in the closed mouth beiug very oblique, placed 

 at an angle of about 45 degrees. The lower jaw very long and strong, 

 its length more than one-third the length of the head, nearly half the 

 length of the head in the adult, its tip, when the mouth is closed, about 

 on a level with the eye. Upper jaw very i^rotractile. Upper lip very thin 

 (for a sucker), and nearly smooth. Snout elevated above the rest of the 

 head, the premaxillary spines usually forming a conspicuous nose. Lower 

 lip moderate, consisting of a broad flap on each side of the mandible, in 

 front reduced to a narrow rim, the surface of the lip nearly smooth, with- 

 out i)apilhie. Nostrils large. Suborbital bones narrow, but rather 

 broader than in Catostomns. Preorbital unusimlly large. I\rucous chan- 

 nels moderately developed. Fontanelle very large. Isthmus rather 

 narrow Pharyngeal bones weaker than usual in Catostomns, the teeth 

 generally smaller. Body rather slender, tapering pretty regularly from 

 the shoulders to the tail, but little compressed. Caudal peduncle rather 

 stout. Fins moderate; the dorsal rays about 12 ; the anal 7. Pectorals 

 rather long, not quite reaching ventrals ; ventrals reaching vent ; anal 

 fin high, reaching caudal; caudal fin rather long, its lobes equal. 

 Stides moderate, large on the caudal peduncle, much smaller and 

 crowded anteriorly, 00-05 in the lateral line, about 18 in a transverse 

 .scries from dorsal to ventrals. Sexual peculiarities unknown. Colora- 

 tion usual. Air-bladder in two i)arts. Size moderate or rather large. 



{■/a<T;j.daj, tO yaWU.) 



