THE CYPRINODONTS. 155 



Orestias Jussieui. 



Orestias Jmsiei Val., 1S46, C. V. Poiss., XVIII, 235, pi. 535; Gtlir., 1S66, Cat., VI, 329; Eig., 1891, 

 P. U. S. Mus., XIV, 65. 



Orestias Jussieui Cast., 1855, Exp. Am. Sud, Poiss., pi. 27, fig- 3; Blkr., 1860, Cypr., 487. 



D. 14 ; A. 13 ; P. 14 ; C. 28. 



In being short and considerably arched in front of the dorsal, as figured 

 by Cuvier and Valenciennes, this species resembles 0. albus and 0. Mens, 

 from which it is easily distinguished by its smooth scales. Between it and 

 O. Affassizii the differences in arch of back and shapes of crown and snout 

 are very marked. Length of head less than depth of body, little less than 

 one third of body without caudal. Crown flattened. Snout massive, twice 

 as long as eye. Mouth large, cleft descending much below the level of the 

 eye, oblique. Eye half as long as snout, one-sixth the length of head. 

 Scales on back forward from the dorsal, and on head and cheeks large, 

 thick, smooth. Suborbital, cheek, and opercle covered with scales. Largest 

 scales above the pectorals. Behind those that are enlarged the scales are 

 thin and bear concentric striaj. Ventral surface naked anteriorly. Color 

 yellowish green, fins pale. Described from four inch specimens. 



Valenciennes says his examples came from Titicaca, Guasacona River, 

 and the Lake Chinchoro, near Cuzco. The dimensions given suggest that he 

 had two species in hand, for part of his details, in regard to crown and 

 length of head, apply to 0. Agassizii and not to the form he figures as 

 0. Jussieui. 



Orestias Incae sp. n. 



Plate III. Fig. 9, teeth. 



B. 5 ; D. 16-18 ; A. 16-18 ; P. 18-20 ; LI. 32 ; Ltr. 16-17; Vert. 13 + 18. 



Body much compressed, depth two fifths of length, without caudal, or one 

 third of total, highest point at first rays of dorsal, nearly straight from snout 

 to dorsal fin. Head narrow, higher than deep, little less than one third of 

 total length ; crown a trifle convex transversely, straight, back becoming 

 slightly arched behind occiput. Snout medium, as long as eye, blunt, broad. 

 Mouth small, vertical, cleft downward almost to lower level of eye. Eye 

 large, as long as snout, two sevenths of head, not quite as wide as inter- 

 orbital space. Teeth few, simple, hooked, apparently in a single series. 

 Pharyngeal teeth stout, with a shoulder. Scales medium, not granulate. 



