eigenmann: fresh water fishes. 317 



* CicJilasonia kvaussii Steindachner. 



* Geophagiis steiiidachneri Eigenmann & Hildebrandt. 

 / Geophagiis crassilabris Steindachner. 



Undoubtedly this is but a small part of the fauna of this basin. As our 

 knowledge stands at present, this basin lacks very largely those Amazonian 

 genera that are also absent from the coastal plain of southeastern Brazil. 

 See later List. Thirty per cent, of its known species are Amazonian. 



4. The Amazon Province. 



East of the Cordilleras, and therefore east of the Magdalena basin, is 

 found the most extensive and intricate fresh water system in the world. 

 It forms a network of rivers practically uninterrupted, extending from the 

 mouth of the Orinoco through the Cassiquiare, Rio Branco, Rio Negro, 

 Rio Madeira, Rio Guapore, Rio Paraguay, Parana and La Plata to Buenos 

 Aires, through 45° of latitude and from Para to within a few miles of the 

 Pacific coast, through 30° of longitude at the equator. 



The connection between the Orinoco and Branco through the Cassi- 

 quiare has been definitely known since Humboldt traversed it. The fol- 

 lowing is from the International Bureau of American Republics, "United 

 States of Brazil," p. 79 : 



"Another remarkable phenomenon of the Paraguay is the mingling of 

 its principal head waters with those of the affluents of the Amazon. An 

 affluent of the Jauru River is sufficiently near the Guapore River to be 

 connected with the latter by a canal. The Aguapehy, another tributary 

 of this river, is separated from the Alegre by a narrow isthmus 5 kilo- 

 meters wide. In the eighteenth century an attempt was made to open up 

 a canal here, and owing to the abundant rains a large canoe of 12 oars 

 succeeded in passing from the one river to the other. One of the gover- 

 nors of the state also endeavored to open up a canal 10 kilometers long 

 in another part of the isthmus, but on account of the small amount of 

 trade it was never completed. This would connect Montevideo and Para 

 by a continental waterway 8300 kilometers long. In the near future it is 

 probable that railways will take the place of the canal. There are many 

 places on the edge of the plateau, farther to the east, where a simple cut 

 of a few meters would connect the tributaries of the Amazon with those 

 of the Paraguay, transforming eastern Brazil into an island. There is a 



