31. CYPRINID^E GILA. 229 



tion plain, darker above. Head 3f ; depth 4. D. 9; A. 9; Lat. 1. 82. 

 Rio Gila and Colorado Basin. 



(Baircl & Girard, Proc. Acacl. Nat. Sci. Phila. 1853, 389; Girard, U. S. Hex. Bound. 

 Surv. lehth. 01 : Leuciscus grahami Giinther, vii, 242: Ptychocheilus rorax Girard, Proc. 

 Acad. Nat. Sci. Phila. 185(5, 209, aud U. S. Pac. R. R. Surv. x, 301. The type of 

 "vorax" examined by us is a true Gila.) 



362. G. affiuis Abbott. 



A species allied to the preceding, described as follows : " The body is 

 slender, tail greatly attenuated, head constituting something more than 

 one-fifth of the total length. Eye rather small, subelliptical, its diam- 

 eter G times in the entire length of the head. The posterior extremity 

 of the maxillary extends to a vertical line drawn posteriorly to the an- 

 terior edge of the orbit. Anterior margin of the dorsal fin nearer the 

 base of the caudal than the extremity of the snout. Anterior margins 

 of the ventral fins somewhat nearer the extremity of the snout than the 

 base of the caudal. The lateral line is nearly concurrent with the ven- 

 tral outline. The numbers of the fin-rays are : D. 10 ; P. 1C ; V. 8 ; A. 







9 ; C. 28." (Abbott.) Dull violet above, pinkish below. Kansas River ; 

 Platte River. (We have some time since examined specimens from 

 Platte River, and thought them distinct from G. robusta and G. grahami, 

 but having lost our notes are unable to add to Dr. Abbott's account.) 



(Abbott, Proc. Acad. Nat. Sci. Phila. 1860, 474.) 



363. G. gracilis Baird & Girard. 



Body slender, the back not much elevated, the caudal peduncle not 

 very slender, about twice as long as deep. Head large, its upper pro- 

 file not very strongly concave. Mouth large, terminal and oblique, the 

 upper jaw scarcely longer than the lower, maxillary reaching past the 

 front of the eye. Interorbital space broad. Pectorals falling consid- 

 erably short of veutrals. Caudal deeply forked. Dorsal well behind 

 ventrals. Head 3; depth 4. D. 9; A. 9; Lat. 1. 88. Gila and Col- 

 orado Rivers. 



(Baird & Girard, Proc. Acad. Nat. Sci. Phila. 1853, 369; Girard, U. S. Pac. R. R. 

 Surv. x, 237: Leuciscus zunnensis Giiuther, vii, 241.) 



** Head conical, scarcely depressed, the profile not concave, 

 a. Belly scaled. 



364. J. cuiiorii Baird & Girard. 



Body slender, the back not notably arched. Caudal peduncle very 

 slender, its least depth about one-fifth its length. Head rather small, 

 conic, scarcely depressed above the eyes, its profile continuous with that 



