152 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



miicli compressed, laucet-sliaped, erect, nearly straight. Upper limb 

 of the pharyngeal bone very broad and concave, separated by a deep 

 notch from the dentigerous portion, the bone thin and brittle. Intes- 

 tinal canal elongate, about 7 times the length of the fish ; i)eritoneum 

 black. Scales small. Lateral line present. Dorsal tin opposite ven- 

 trals. Basal rays of caudal largely developed. Anal basis short. 

 Pseudobrauchise none. Gill-rakers moderate, clavate, the inner edge 

 fringed. Size large. This genus is related to Chondrostoma, differing 

 chiefly in the absence of pseudobranchiai and of the horny mandibular 

 plate. {opO<k, straight; oomv^ tooth.) 



l^S. O. anicB'oU'pidotus (Ayres) GnL 



Body elongate. Head moderate ; the snout very broad ; eye small, 



about half the length of the snout. Mouth terminal, somewhat oblique, 



broad, the maxillary not extending to the eye. Upper head of surfsice 



flattish, with two bony ridges. Fins rather large ; the caudal strong. 



Coloration plain. Lateral line decurved. Head 4; depth 4i. D. l>: 



A. 8 ; scales 21-105-12 ; Vert. 24 + 20. Teeth 0-6 or 6-5, formed much 



as in Campostoma, but longer. Size large. L. 12 inches. Itivers of 



California ; Great Basin of Utah ( Yarrow). 



(Gila microlepidota Ayres, Proc. Cal. Acad. Nat. Sci. i, "21, 18r)5; Girartl, U. S. Pac. 

 R. R. Surv. Fish. 237, fig.; Giinther, vii, 275.) 



74.— I.AVINIA Girard. 



(Girard, Proc. Acad. Nat. Sci. Pliila. 1854,137: type Lavinia exilicauda B. & G.) 



Bod^' elliptical, elevated, moderately compressed, rapidly contracted 

 to the slender caudal peduncle. Head small, conical. Mouth mo<l- 

 erate, terminal, oblique; the lower jaw included. Scales moderate, 

 not closely imbricated, the exposed surfaces somewhat hexagonal. 

 Lateral line decurved, complete. Belly behind ventrals entirely scaled. 

 Dorsal fin well behind ventrals, its last ray just in front of the begin- 

 ning of the anal, which is rather elongate. Caudal flu little forked, its 

 rudimentary- basal rays much increased in number and very strong. 

 Intestinal canal elongate, 3 times the total length of the fish; i)e- 

 ritoueum dark. Teeth 4-5 or 5-5, scarcely hooked, cultriform, with 

 rather broad but shallow grinding surface, the largest standing uj) 

 well above the surface of the bone. Gill-rakers rather long and slen- 

 der; pseudobranchioe large. Size large. (Lavinia, a classical name, 

 without special application to these fishes.) 



