374 FISHES OF WESTERN SOUTH AMERICA 
brown. In these the fins were always lightly punctulate or not at all. Specimens 
collected from the clearer waters of Lakes Titicaca, Umayo, etc., were the most 
deeply colored and rich in var. ‘nornata. 
In large series it was often possible to arrange the specimens in order of size, 
and find that there was a rather regular transition from the crequii type through 
var. typica to ¢nornata, the largest. One specimen of 70 mm. still bore faint traces 
of the crequii spots, while the ovaries were becoming enlarged. The 70-90 mm. 
specimens (one from Lake Ascotan at 65 mm.) appear to be at the threshold of 
sexual maturity. The immature specimens are commoner in the smaller streams. 
Resumé: the study of numerous populations shows that Pellegrin’s varieties 
are without the geographic isolation necessary to rank as subspecies. They are 
open to both genetic and ecological interpretation, and a definite correlation with 
age. 
My collections from about Tirapata, Pucara, ete., reveal no trace of forms 
which I could identify as Boulenger’s O. tirapatae, the region yielding only O. 
agassizii varieties and miller’. His description, scale count, ete. would indicate 
that he had agassizii. Boulenger was influenced by the fact that his specimens 
attained sexual maturity at about 65 mm., but my own specimens of agassizi7 
(see above) were beginning to pass into the adult stage at little greater size. 
Fishes of minnow form, elongate, moderately convex dorsal and ventral 
profiles, in older specimens highest at the occiput and tapering thence caudally; 
becoming much compressed with age; only moderate in width, without strong 
angularities. Width 1.4 in depth, the latter 3.3 in the length; head short, 3.4-3.7 
in the length; eye 1.7—2.0 in the interorbital space; eye in head (smaller specimens) 
3.7-4.4, 4.8-5.3 (in larger ones); the posterior margin of the eye midway of the 
head. Head convex both ways, mouth wide, vertical, thin-lipped, teeth sparse; 
snout both long and wide, containing the eye 1.5 times; the eye small and round. 
Tightly scaled except snout, no naked areas, little irregularity in scale rows except 
across the shoulders and predorsal; vertebral series 17-20, usually irregular; narrow 
scaleless portion of venter often bridged by several rows of scales before vent; 
bucklers of cheek and opercle becoming thickened and denser with age; infra- 
orbital with few or none in the young, but outlined by a row of pores; in older 6-12 
close-set bucklers extending forward well beyond the orbit; bases of fins without 
scales. Opercle short with a wide lateral angle. 
D. 13-15 (exceptionally 17); A. 15-16; caudal broad and truncate. 
Colors as described above, and by Pellegrin; oldest specimens as described 
by Garman; darkest and lightest specimens equally devoid of spots or stripes 
485. ORESTIAS MULLERI Valenciennes 
Plate X XI, fig. 1 
Orestias miller? Cuvier and Valenciennes, 1846, Hist. Nat. Poiss., X VIII, 179; 
Garman, 1895, Mem. Mus. Comp. Zool., XTX, 149; 
Higenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 461; 
Evermann and Radcliffe, 1917, Bull. U.S. Nat. Mus., no. 95, 40. 
