10. OEESTIAS. 329 



a. Female, 8 inches long. From Mr. Pentland's Collection. 



h-d, e-g. Half-grown and young. From Mr. Pentland's Collection. 



2. Orestias pentlandii. 



Cm. Sf Val. xviii. p. 230, pi. 533, cop. by Casteln. Anim. Amdr. Sud, 

 Poiss, pi. 27. fig. 2. 



D. 13-15. A. 16-17. L. lat. 60. 



Body rather elongate than stout ; head three-fifths as high as 

 long, its length being one-fourth of the total (^without caudal). Eye 

 rather small, nearly one-sixth of the length of the head in large 

 examples, and one-fourth in younger ones. Snout of moderate 

 length, longer than the e)'e, truncate, the lower jaw being vertically 

 directed upwards ; prajorbital subquadrangular, rather longer than 

 high. The scales on the cheek leave a broad ring round the orbit 

 and a large space behind the maxillary uncovered. Adult specimens 

 have the scales on the head and the upper part of the trunk but 

 slightly granular, and only those of a series running above the oper- 

 culum are conspicuously enlarged. The length of the posterior limb 

 of the praeoperculum is more than two-thirds of that of the lower. 

 Pectoral terminating at a great distance from the vent. The distance 

 between the dorsal and caudal fins is more than the length of the base 

 of the former. 



Lake Titicaca. 



a-6. Females, 7^ inches long. From Mr. Pentland's Collection. 

 c. Several young and half-grown specimens. From Mr. Pentland's 

 Collection. 



3; Orestias jussiei. 



Cuv. 8f Vol. xviii. p. 235, pi. 535, cop. by Casteln. ^nim. Amh; Sud, 

 Poiss. pi. 27. fig. 3. 



D. 14. A. 15. L. lat. 33. 



Body rather stout, neck elevated and much arched ; head nearly 

 three-fourths as high as long, its length being contained thrice and 

 a third in the total (without caudal) ; anterior part of the head com- 

 pressed : snout as long as the eye, truncate, the lower jaw being 

 vertically directed upwards. Eye one-fourth of the length of the 

 head in a specimen 3| inches long. Praeorbital irregular in shape, 

 deeper than long. Cheeks entirely covered with hard, horny scales ; 

 the scales on the trunk and on the head are enlarged, very thick and 

 horny, but smooth. The length of the posterior limb of the prte- 

 operculum nearly 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. Three and a half inches long. From Mr. Pentland's Collection. 



