3d CATCSTOMIDiE CATOSTOMUS. 125 



?narke(l ; the fins bigber in the male and the anal somewhat swollen and 

 tuberculate in the spring. Breeding males in some species with a rosy 

 or orange lateral band. Air-bladder with two chambers. Vertebroe in 

 C. commcrsoni and C. nigricans 45-47. Species very numerous, all be- 

 longing to the United States, excei)t the Siberian C. rostratus Tilesius. 

 (z«rw, interior; azoii.a^ mouth.) 



* Scales very small, mm-.h reduced aud crowded anteriorly, H:?-lir> in the lateral line. 

 (C«tos/o?)i«s. ) 

 a. Fontauello almost obliterated, reduced to a narrow .slit ; eacli jaw with a well- 

 developed cartilaginous sheath (as in Vaniosieua). 



129. C. discobolus Cope. 



Body subterete, compressed behind, the depth 5 in length. Interorl)- 

 ital space 2 in liead. Head quite short, broad and rounded above, 4^ in 

 length. Eye small, far back and high u}), G in head. Mouth very 

 large, inferior, beneath the projecting snout. Upper lip very full, pen- 

 dent, with about 5 rows of tubercles. Lower lip very full, moderately 

 incised, with about 10 rows, a notch separating the upper lip from the 

 lower. Each jaw with a slightly curved cartilaginous sheath on its 

 edge, the two parallel with each other and fitting closely together. 

 Fins snuill. Dorsal 11 ; caudal little forked; scales 15-90-11, irregular. 

 Colors dusky. Size small. Idaho to Wyoming and Arizona. 



(Cope, Haydeu's Geol. Surv. AVyom. Terr. 1870,435; Jowlau, 1. c. 179.) 



aa. Fontanelle well developed ; jaws without evident cartilaginous sheath. 

 1). Up])er lip veiy broad, with several (5 or (>) rows of large papilhe. 



130. C. Iniipicitais Baird «& Girard. 



Bod,y slender and elongate ; the caudal peduncle especially long aud 

 verj' slender; the depth 5^ in the length. Head moderate, 4.^- in length, 

 rather slender, with prominent snout and rather contracted, inferior 

 mouth. Outline of the mouth triangular, the apex forwards. The lips 

 very thick, greatly developed; lower lij) incised to the base; its pos- 

 terior margin extending backwards to opposite the eye. Jaws with a 

 slight cartilaginous pellicle. Eye small, high up. Preorbital bone 

 broad, scarcely twice as long as dee.p. Scales long and low, posteriorly 

 rounded, their horizontal diameter greater than the vertical, 17-08 to 

 105-17. Fins excessively developed, especially in the males, the free 

 border of the dorsal deeply incised. Height of each of the three verti- 

 cal fins in the males greater than the length of the head. Dorsal 13, in- 

 serted nearer snout than base of caudal. Caudal very strong, the rudi- 

 mentary rays at its base unusually developed. Least dei)th of tail less 



