330 CYPRINODONTIDJ?. 



4. Orestias owenii. 



Orestias owenii, Cuv. ^ Val. xviii. p. 241. 



agiissizii, Cuv. Sf Val. xviii. p. 238, pi. 536. 



tschudii, Casteln. Anim. Amer. Sud, Poiss. p. 51, pi. 27. fig. 1. 



D. 14-15. A. 13-16. L. lat. 35. 

 Body rather stout, neck slightly arched ; head nearly three-fourths 

 as long as high, its length being a little more than one-fourth of the 

 total (without caudal). Eye of moderate size, one-fourth of the 

 length of the head in a specimen 4 inches long. Snout of moderate 

 length, as long as the eye, obtuse, the lower jaw being obliquely 

 directed upwards. Proeorbital irregular in form, higher than long : 

 it is crossed hj a series of pores running all round the orbit ; another 

 series along the limb of the prseoperculum. The scales on the cheek 

 advance to below the eye and to the prseorbital ; the scales on the 

 head and on the trunk are, in adult specimens, somewhat enlarged, 

 thick and horny, but smooth. The length of the posterior limb of 

 the pra^operculum equals that of the lower. Pectoral terminating 

 at some distance from the vent. The distance between dorsal and 

 caudal fins equals the length of the base of the former. 



Lake Titicaca. 

 a, b, c, d, e. Manj- specimens, from 2 to 3| inches long. Lake 



Titicaca. From Mr. Pentland's Collection. 

 /-?. From 2 to 8 inches long. Lake d'Urcos. From Mr. Pentland's 



Collection. 



5. Orestias mlilleri. 



Orestias miilleri, Cuv. ^- Val. xviii. p. 240 (half-grown). 

 albus, Cuv. Sf Val. xviii. p. 242, pi. 537. 



D. 12-14. A. 13-15. L. lat. 32. 



Body stout, neck elevated and arched ; head two-thirds as high as 

 long, its length being one-third, or in adult specimens a little more 

 than one-third, of the total (without caudal) ; snout rather short, as 

 long as the eye, truncate, the lower jaw being vertically directed 

 upwards. Eye one-fifth or one-sixth of the length of the head in 

 specimens 6 inches long, and two-sevenths in specimens of 3 inches. 

 Pra^orbital subtriangular, higher than long, broadest below. The 

 scales on the cheek leave a broad ring round the orbit and a large 

 space behind the angle of the mouth uncovered ; the scales on the 

 head and on the trunk are, in adult specimens, enlarged, strongly 

 granulated, very thick and horny. The length of the posterior limb 

 of the prseoperculum equals that of the lower. Pectoral terminating 

 at a short distance from the vent. The distance between dorsal and 

 caudal fins is equal to, or rather more than, the length of the base 

 of the former. 



Lake Titicaca. . 



a-f. Adult female (6 inches long) and half-grown examples. Lake 

 Titicaca. From Mr. Pentland's Collection. 



if. Half-grown. Andes de S. Antonio. From Mr. Pentland's Col- 

 lection. 



