364 FISHES OF WESTERN SOUTH AMERICA 
Pellegrin, 1906, Poiss. Lacs Hauts Plat. Amér. Sud, 126, 136, fig. 19iii; 
Kigenmann, 1910, Rept. Princeton Uniy. Exped. Patagonia, III, 461; 
Evermann and Radcliffe, 1917, Bull. U. S. Nat. Mus., no. 95, 42; 
Rendahl, 1937, Ark. Zool. Stockholm, 29A11. 
Orestias neveut Pellegrin, 1904, Bull. Soc. Zool. France, X XIX, 95; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 461; 
Evermann and Radcliffe, 1917, Bull. U. S. Nat. Mus., no. 95, 42. 
Lake Titicaca and affluents 
16081, Puno bay, Lake Titicaca, Allen, November, 1918. 
16091, 18, 34-53 mm., Bay of Huancané, Allen, December, 1918. 
16120, 1, 76 mm., Rio Caminaque, Allen, December, 1918. 
16127, 4, 26-69 mm., Rio de Azdngaro, Allen, January, 1918. 
One of the species at least locally known as carache, but less numerous ac- 
cording to Garman, and less numerous in my collection than nearby luteus. Called 
also silgo according to the Indians of Moho, Garman reports. 
Garman amplifies the original brief description as follows: ‘“‘snout large, 
wide, and deep... teeth not as numerous nor as strong as those of O. cuvieri,” 
which makes it doubtful if his specimens were albus. Further on he says: ‘‘the 
large snout... distinguish it from O. luteus, breadth at the mouth makes the head 
less pointed,’ just the reverse of what I find in my specimens. I fear that either 
Garman or myself has interchanged these two species. Here as elsewhere much 
confusion has been injected into the literature by Valenciennes’ figure and descrip- 
tion. In fact, it is doubtful that he, himself, had O. luteus and albus clearly in 
mind, for he comments that Jussieu’s drawing would fit the one about as well as 
the other. 
Pellegrin separated his neveui from albus largely on the want of naked patches 
on the back. Since such areas appear occasionally on many species and with 
constancy in few or none, it is not of diagnostic value. Starks either considered 
this character important, or was “thinking aloud” about them in describing their 
variations at some length. His description of O. lutews is such as to make it clear 
that he had correctly separated the two species, except that he says the mouth is 
smaller. 
In my collections I find four specimens of large size, and several smaller, which 
conform fairly well to previous concepts of albus, while my material on O. luteus 
is quite abundant, and from many localities, forming an unbroken series up to the 
blunt-nosed, 200-mm. specimens from Lake Umayo. 
My specimens from the Azingaro, 61-67 mm., correspond very well to Valen- 
ciennes’ figure in general form, length of head, shape of opercle, ete., differing in the 
form of the mouth, in the scalation of the pre-pectoral area and sides of the belly. 
They have the “clouded blotches” of Garman’s younger specimens. 16120, a 
little larger, has the head wider, width equal to depth, and 1.3 in the length of the 
head; mouth narrower. 
Rather strongly but evenly arched on the dorsal profile, highest above the 
pectoral base, depth 1.3 in the length of the head, slightly depressed at the occiput. 
Shorter, more robust, more rounded than O. luteus of equal size, nowhere as angular, 
