30. CATCSTOMID^E - C'ATOSTOMUS. 125 







marked ; the fins higher in the male and the anal somewhat swollen and 

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

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

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

 longing to the United States, except the Siberian C. rostmtus Tilesius. 

 , inferior; a-o<}.a, mouth.) 



* Scales very small, much reduced aud crowded anteriorly, 83-115 in the lateral line. 

 (Catostomus.) 



a. Fontauelle almost obliterated, reduced to a narrow slit; each jaw with a well- 

 developed cartilaginous sheath (as in Pantostcus'). 



129. C. diiscotoo&MS Cope. 



Body snbterete, compressed behind, the depth 5 in length. Interorb- 

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

 length. Eye small, far back and high up, 6 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 fall, 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 small. Dorsal 11 ; caudal little forked; scales 15-90-11, irregular. 

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



(Cope, Hayden's Geol. Surv. Wyom. Terr. 1870, 435; Jordan, 1. c. 170.) 



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

 i. Upper lip very broad, with several (5 or G) rows of large papillae. 



13. C. latipiMBBls Baird & Girard. 



Body slender and elongate ; the caudal peduncle especially long and 

 very slender; the depth 5^ in the length. Head moderate, 4f 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 lip 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 deep. Scales long and low, posteriorly 

 rounded, their horizontal diameter greater than the vertical, 17-98 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 depth of tail less 



