eigenmann: fresh water fishes. 



339 



lo. The La Plata Province. 



Of the streams draining toward the south nothing is known ichthyo- 

 logically of the Uruguay and very little of the upper Parana, while the 

 Paraguay, owing to the work of Natterer, Ternetz and Anisits, is one of 

 the best known regions of South America. 



The Paraguay is a lowland stream, the elevation at its sources at 

 Cuyaba being but 200 m. At Corumba it has an elevation of 140 m., at 

 Puerto Pachero 100 m., at Asuncion it has an elevation of about 70 m. 

 Its sources are in contact with the sources of the Guapore, a tributary of 

 the Madeira, and those of the Tapajos. 



The upper Parana is, in distinct contrast to the Paraguay, a mountain 

 stream arising in the Serra da Mar and the southward extension of the San 

 Francisco plateau. The Rio Grande de Minas, one of its largest tribu- 

 taries, has at Porta da Rifano an elevation of 590 m. The upper Parana 

 is separated from the lower Parana by the Gran Salto de Guaira, where it 

 leaps over falls of 18 m. to the lowland. Its upper tributaries arise mostly 

 in the coast range near the Atlantic coast and reach the main stream after, 

 numerous falls. 



A list of the fishes of the Paraguay basin is sufficiently startling on 

 account of the few things peculiar to it, and the many species and genera 

 it has in common with the Amazon, to warrant giving it in detail. 



A separate list of species and genera for the Parana, La Plata and Rio 

 Grande do Sul gives us an idea of the relationship of the fauna to that of 

 the Amazon and to that of southeastern Brazil. 



There is no room for doubt on the source of the fish fauna of this 



