290 MEMOIRS OF THE CARNEGIE MUSEUM. 



with a few other mountain forms Uke Grimdulus at Bogota, Astroblepus and Bi^y- 

 conamericus in the High Andes from Panama to Cuzco, and Oresteas in Lake Titi- 

 caca. The only fish found by Haseman in the headwaters of the Rio das Velhas 

 was a member of this genus. Species of Pygidium were found in the most elevated 

 places visited by Henn in Colombia and Ecuador. In Titicaca they are of con- 

 siderable economic importance, and on the plains of Bogota, the nearly related 

 genus Eremophilus is of prime economic importance. They are found in Guiana 

 and in the Amazon, but only as dwarfs. They also flourish in the mountain- 

 streams of southeastern Brazil, but the species do not reach the size of those in 

 Peru. Some of the species are found on both slopes of the Andes, but, unlike low- 

 land species of other fishes, which if found on both sides of the Andes, usually have 

 a very wide distribution, the species of the genus Pygidium all have rather limited 

 ranges. Many of them are restricted to a single small river and no river has many 

 species. In 1910 I said (Patagonia Report, p. 248), "There is no place on record 

 harboring more than one species of this genus." This statement requires modifica- 

 tion. While, so far as known, many basins contain but a single species, a number 

 of other smaller rivers, the Iguape for instance, contain several. Judging by its 

 wide distribution, both horizontally and vertically, the genus is probably one of 

 very long standing. 



The species of the genus need a careful revision, but the descriptions usually 

 omit mention of the character of the teeth, and no collection contains any great 

 percentage of the total number of species described. Furthermore, judging from 

 the fact that they are abundant in all the high mountain-rills and even in lowland 

 rapids, and that from the stretch from Caracas along the eastern slope of the 

 Andes to Peru we have only the types of the species P. meridoe, kneri, metce, and 

 dorsostriatum, the revision of the entire genus may be left in abeyance. The species 

 are grouped according to the areas from which they have been reported. 



CHILEAN SPECIES 



The species from C'hile where the members of the genus Hatcheria have in part 

 ■ replaced them, are P. marmoratum. (Philippi), P. palleum (Philippi), and P. 

 tigrinum (Philippi) . ' ^ 



1. Pygidium marmoratum (Phihppi). 



Trichomycterus marmoratus Philippi, Mb. Ak. Wiss. Berlin, 1866, p. 714; Eigen- 

 MANN & EiGENMANN, Occasional Papers Cal. Acad. Sci., I, 1890, p. 326; 

 Delfin, Catalogo de los Peces de Chile, 1901, p. 31. 



'* In addition to the three species described by Pliilippi, Pygidium nigricans (Cuvier & Valencien- 

 nes) is recorded from Chile by Gay. This is probably an error. 



