38 BIJLLETIISr 95^ UISTITED STATES NATIONAL MUSEUM. 



a^ Form medium elongate, in adult. 



<f. Scales striate ; crown flat ; mouth large , mulleri, p. 40. 



d^. Scales smooth, in part ; crown convex ; mouth small. 



&. Dorsal rays 15 or 16 ; anal rays 16 or 17 tschudii, p. 40. 



c^ Dorsal 13-15; anal rays 13-15 agassizii, p. 4,0. 



&. Dorsal rays 13; anal rays 13 ^ owenii, p. 4:2. 



a^ Form short. 



f. Belly naked. 



g^. Body rounded ; head rounded. 



/i\ Mouth small; f^cales striate oUvaceus, p. 42. 



g\ Body compressed; head angulai*. 

 i\ Scales granulate, in part. 

 f. Snout large; mouth wide. 



fc*. Back only partly scaled all)us,p.42. 



k^. Back entirely scaled neveui, p. 42, 



f. Snout narrow; mouth small luteus,p.42. 



i'. Scales smooth, in part; back high jussiei,p. 42. 



f. Belly covered with scales. 



r. Body much compressed incae, p. 42. 



51. ORESTIAS CUVIERI Valenciennes. 

 OMANTO. 



Orestias cuvieri Valenciennes, L'Inst., vol. 7, 1839, p. 118 ; Lake Titicaca. — 

 CuviEE AND Valenciennes, Hist. Nat. Poiss., vol. 18, 1846, p. 168 (225), 

 pi. 532. — Garman, The Cyprinodonts, Mem. ]\Ius. Comp. Zool., vol. 19, 

 1895, p. 147, pi. 3, fig. 11 (teeth). — Staeks, Fishes from Ecuador and 

 Peru, Proc. U. S. Nat. Mus., vol. 30, 1906, p. 779. 



Orestias cuvierii Cope, Proc. Amer. Philos. Soc, vol. 17, 1877, p. 44. 



One specimen, field, No. 555, 20.8 cm. in length, from Lake Titi- 

 caca near Puno. 



Head 2 in length ; depth 4 ; eye 6.6 in head, 2 in snout ; snout 3.7 ; 

 interorbital 3.3 ; length of pectoral 2 ; base of pectoral 4 ; D. 16 ; A. 18 ; 

 scales 14-41 ; 23 scales on median line of back in front of dorsal. 



Body elongate, slightly compressed; caudal peduncle rather slen- 

 der, broadening at base of the fin: head large, one-third of length 

 without caudal; crown broad, depressed and concave at occiput and 

 snout, flattened in the middle; snout large, broad, blunt, rounded, 

 nearly twice as long as eye; chin vertical; mouth wide, oblique, 

 cleft reaching below the lower level of orbit ; teeth strong, in bands, 

 numerous, hooked, subconical ; eye medium ; scales of head and shoul- 

 der granular; a series of about 20 large vertebral scales in front of 

 tlie dorsal; scales of the lateral line larger than those on each side 

 of it; belly scaleless. On young individuals all the scales are flat, 

 thin and concentrically striate; the granulation and thickening ap- 

 pear first at the head, then gradually extend farther back. Dorsal 

 origin near halfway from head to caudal; fin low, rounded on upper 

 margin, third ray above origin of anal; anal extending a little far- 

 ther back than dorsal, in base and fin; pectorals about the size of the 



