Jordan and Evermann. Fishes of North America. 309 



APOCOPE, (awo/coTn;, a cutting away, from the imperfect lateral line): 

 a. Teeth two-rowed, usually without grinding surface. 



6. Dorsal fin rather low, and not strongly falcate; caudal lobes obtuse. 



c. Snout rather long, less than 4 in head, resembling that of Rhinichthys. 

 d. Scales small, usually more than 70 in lateral Hue. 



e. Head 4; snout 4; scales very small, about 89 in lateral line. OSCTILA, 510. 

 ee. Head rather long, about 4%; scales larger, about 78 in lateral line. 



YARROWI, 611. 



eee. Head shorter, 4% to 5; scales about 74. COUESII, 512. 



dd. Scales larger, fewer than 70 in lateral line. 



/. Scales about 65; snout 2%; eye 5 to 5%. ADOBE, 513. 



f. Scales large, usually 52 to 65. 



g. Body quite deep, depth 3% to 4 in length; fins low. NEVADENSIS, 514. 

 gg. Body more slender, depth 3% to 5 in length. 



h. Scales moderate, usually fewer than 70. NUBILA, 515. 



bb. Dorsal fin high and strongly falcate. 



i. Inner rays of ventral fins without membranous stays joining them to the body. 

 j. Eye large, 3 in head; scales large, about 56 in lateral line. VELIFERA, 516. 



jj. Eye smaller, 3% to 4 in head; scales smaller, 63 to 70 in lateral line. 



UMATILLA, 517. 



it. Inner rays of ventral fins united to body by 2 or 3 membranous stays. 



FALCATA, 518. 



AGOSIA : 



ao. Teeth one-rowed, 4-4, with grinding surface; scales very small; intestinal canal somewhat 

 elongate. CHRYSOGASTER, 519. 



Subgenus APOCOPE, Cope. 



510. AGOSIA OSCULA (Girard). 



Head 4 ; depth 4f ; eye 4, shorter than snout. D. 8 ; A. 7 ; scales 18-89-15 ; 

 teeth 1, 4-4, 1. Body rather elongate, the tail stout ; muzzle obtuse, but 

 narrowed anteriorly, not overhanging the mouth; barbel small, some- 

 times obsolete. Scales very small. Dusky olive above, a blackish lateral 

 band; males with axils of pectorals and ventrals scarlet; a scarlet patch 

 above gill opening and one on side of muzzle. Length 2 to 3 inches. 

 Lower Colorado and Gila rivers; not rare, (osculus, small mouthed.) 



Argyreus osculns, GIRARD, Proc. Ac. Nat. Sci. Phila., 1855, 186, Babocomori Creek, a tributary 



of the Rio San Pedro, Arizona. (Type, No. 50. Coll. Clark.) GIRARD, U. S. & Hex. 



Bound. Surv. Zool., 47, plate xxvn, figs. 9 to 12, 1859. 

 Argyreus notabilis, GIRARD, I. c., 1856, 186, Rio Santa Cruz, Sonora, a tributary of the Rio 



San Pedro, which is a tributary of the Rio Gila. (Coll. Clark.) GIHABD, Mex. Bound. 



Surv. Zool., 47, plate xxvn, figs. 5 to 8, 1859. 

 Ceratichthys vetitricoms, COPE, Proc. Amer. Philos. Soc. Phila., 1874, 136, Arizona ; Plagop. 



Ichth. Utah, 10, 1874. (Type, No. 15784. Coll. Newberry.) 

 Apocope venlricosa, COPE & YARROW, Zool. Wheeler Surv., 648, plate xxvm, figs. 1 and la, 1875, 



(1876). 

 Apocope oscula (in part) and venlricosa, JORDAN & GILBERT, Synopsis, 211, 1883. 



511. AGOSIA YARROWI, Jordan & Evermann. 



Head 4i ; depth 5 to 51; eye 5| to 6; snout short, obtuse, 2 to 2f. 

 D. 7; A. 7; scales small, averaging about 16-78-13. Barbel small but 

 distinct. Body elongate, little compressed; head long and rather heavy, 

 bluntish, upper lip with or without narrow frenum joining it mesially 

 to snout; the frenum present in about half of our many specimens; lips 

 full, maxillary about 3i in head. Lateral line complete. Dorsal fin well 

 backward, its origin about midway between base of caudal and eye; 



