FISHES OF WEST COAST OF PEETJ. 39 



anal, reaching halfway to vent. Caudal broad, hinder margin con- 

 cave, more deeply indented in the young. (Garman.) 



In this individual the caudal peduncle is not slender as in 0. 

 pentlandii, and the scaling of the head is very different ; head naked, 

 save for a few scales on top, cheek, and opercle ; body scales anteriorly 

 rugose ; naked area on either side of median line of back not so large 

 as in other specimens examined. This species is readily recognized 

 from the others by the elongate head, large mouth, and well-devel- 

 oped teeth. 



Color in alcohol, flesh-colored, dusky brownish on back, but much 

 lighter than in our examples of O. pentlandii. 



Common in Lake Titicaca. 



52. ORESTIAS PENTLANDII Valenciennes. 

 BOGA. 



Orestlas pentlandii Valenciennes, L'Inst., vol. 7, 1839, p. 118 ; Lake Titi- 

 caca. — CuviEB and Valenciennes, Hist. Nat. Polss., vol. 18, 1846, p. 

 172 (230), pi. 533. — Gaeman, the Cyprinodonts, Mem. Mus. Comp. 

 Zool., vol. 19, 1895, p. 148. 



Orestias Mirdit Cope, Journ. Phila. Acad. Nat. Sci., 1785 (1874-81), p. 185; 

 Lake Titicaca. 



Oriestias pentlandii Steindachner, Herpet.-iclithyol. Ergebnisse einer Reise 

 nach Siidamerika, Denkschr. Akad. Wiss. Wien, vol. 72, 1902, p. 58, 

 pi. 4, fig. 4.— Pellegrin, Bull. Soc. Zool. France, vol. 29, 1904, p. 92.— 

 Staeks, Fishes from Ecuador and Peru, Proc. U. S. Nat. Mus., vol. 30, 

 1906, p. 779. — Pellegein, Poiss. Lacs Hants Plateaux de I'Amer. du 

 Sud, 1906, pp. 126, 127, 129, fig. 19i. 



Four specimens, field No. 554, 18.1, 18.8, 19.5, and 20 cm. in length, 

 from Lake Titicaca, near Puno. 



Head 3.38 to 3.46 in length; depth 3.9 to 4.2; eye 5.37 to 5.76; 

 snout 3,2 to 3.5; interorbital 2.58 to 2.68; caudal peduncle 2.68 to 

 2.88; D., 13-15; A., 15-17; scales about 55. 



Body elongate, slightly compressed; caudal peduncle long and 

 slender, broadening at base of caudal, much slenderer than in O. 

 cuvieri; head short, broad at occiput, but narrowing toward tip of 

 snout; snout blunt, rounded, chin vertical, lower jaw not projecting 

 so strongly as in 0. cuvieri; mouth moderate, nearly vertical, cleft 

 of mouth reaching lower level of eye; teeth elongate, hooked, in a 

 single row in jaws, easily broken, comparatively few; interorbital 

 broad, rounded, upper profile of head comparatively straight or 

 with a slight depression in front of eyes; insertion of dorsal slightly 

 nearer base of caudal than posterior border of opercle, or midway 

 between the two; caudal concave; insertion of anal under second 

 dorsal ray. Scales small, thin, somewhat deciduous, those about 

 head and shoulders somewhat rugose, this characteristic of the scales 



