152 THE CYPEINODONTS. 



Orcstias affinis is apparently a variety of 0. Agassizii, from •which it differs 

 in being smaller, shorter, stouter, and lighter olive in color. There are four 

 series of scales below the eye, and the young are spotted, freckled, and trans- 

 versely blotched on the hinder part of the back, or streaked across the fins 

 very much as in Agassizii. The teeth form a band in which the outer series 

 is larger. The vertebral series of scales are rather irregular in front of the 

 dorsal. There are 15 or 16 + 18 vertebra). A number of specimens of three 

 and a quarter inches or less were taken in Lake Umayo. 



Orestias Owenii. 



Orestias Owenii Val., 1846, C. V. Poiss., XVIII, 241 ; Blkr., 1860, Cypr., 487 ; Gthr., 1866, Cat., VI, 

 330, in part. 



D. 13; A. 13; P. 17; C. 31. 



Height of body, or length of head, one fourth of the total length. 

 Muzzle large, rounded. Fins as in the other species. A narrow band or a 

 line traverses the length of the body. On larger individuals the black line is 

 pale upon a silvery band. Appears to be always .small. From lake Urcos, 

 south of Cuzco, 13,000 feet above the sea. The proper position for this form, 

 so far as may be determined from the description, seems to be that of a 

 variety under the species 0. Agassizii. 



Orestias olivaceus sp. a. 



B. 5; D. 15; A. 16-17; P. 20-22; LI. 32; Ltr. 14; Vert. 13 + 18. 



Body short, compressed, slightly arched from occiput to caudal, in depth 

 nearly one third of the length without the caudal fin. Head broader than 

 high, swollen at the cheeks, one third as long as the body to the caudal 

 base ; crown convex between and in front of the eyes, rather concave at the 

 occiput. Snout short, as long as the eye, comparatively narrow, blunt, 

 rounded. Mouth small, vertical, cleft reaching downward little below the 

 level of the middle of the eye. Teeth slender, subconical, hooked, in a 

 single series. Eye medium, one fifth of the head, as long as the snout, 

 half as wide as the interorbital space. Scales large, with small granula- 

 tions and striae that are quite harsh to the touch, some near the head thicker 

 and convex, three vertebral series larger and regular ; cheek scales in three 

 series, below the hinder half of the eye ; a naked space around the eye, 

 enclosed by a series of pores. Fins medium, broad ; dorsal midway from 

 occiput to tail, its base longer than the distance between it and the caudal ; 



