520 EIGENMANN— ORIGIN OF FISHES OF THE 



gone such modifications southward and northward of the Bio Bio 

 (where it is typical for the genus), that at least three species are 

 recognizable. 



The peje reyes, Aiistromenidia, Basilichthys and Cauque are of 

 great economic importance. Austronicnidia is confined to the ocean. 



Basilichthys is found in the rivers from the Rimac south. 

 Three species are recognizable, one in Peru, one in Chili, north of 

 Santiago, the third from Santiago southward. Cauque is found in 

 the rivers and lakes of Chili and Patagonia from La Serena south. 



Perch-like fishes of the genus Percichthys are abundant in Chili 

 from the Aconcagua south to Cape Horn and in Patagonia. 



Percilia is a miniature of Percichthys. It is brilliantly colored 

 and has both the appearance and habit of the North American 

 darters. 



Of great interest are the species of the genera Aplochiton and 

 Gaiaxias, the latter found in Australia as well as in Chili. 



One of the species of Aplochiton (marinus) certainly lives in 

 the sea as well as in fresh water. In the sea it is colorless, in the 

 rivers it becomes covered with roundish spots. Another species, 

 Aplochiton zebra, lives and spawns in fresh water. It has cross- 

 tars of varying number, width, and intensity, and is at its best in 

 small brooks. A third species (tcsniatus), in many ways intermediate 

 between the two, lives largely in lakes. 



Of the genus Galaxias, two species are very abundant, while 

 another one, glohiceps, has been taken in but one locality. Galaxias 

 maculatus is very abundant from the Bio Bio south. It is very 

 probable that it descends to the sea to spawn. In April or there- 

 about great masses of its young ascend the rivers in which it occurs. 

 Galaxias platei is principally at home in small brooks. 



A related minute fish, Brachygalaxias hullocki, is confined to 

 Chili. 



A species of Orestias {Agassizii) occurs at L. Ascotan, just 

 within the limits of Chili along the railway between Antofagasta and 

 La Paz. The genus Orestias occurs most abundantly in Lake Titi- 

 caca. Since tributaries of the Desaguadero, the outlet of Lake 

 Titicaca, flow for some distance through Chilian territory, other 

 species of Orestias technically belong to the favma of Chili. They 



