eigenmann: fresh water fishes. 319 



Neither the Orinoco nor the Paraguay contains any fishes that would 

 cause the slightest surprise if they were found at Manaos or any other 

 part of the Amazon. Every collection made in the Paraguay in recent 

 years has brought to light more types hitherto considered Amazonian and 

 has increased the number of genera and species that the two systems 

 have in common. Very little is yet known of the Orinoco. 



The list of Amazonian species is too long to give here. The Amazon- 

 ian species have therefore been marked A in the general list of the species 

 forming Part III of this report. They number about 700. 



5. The Guiana Province. 



The Guiana Province, including one of the oldest land masses, is drained 

 by the Cachipur, Oyapoc, Cayenne, Mana, Maroni, Surinam, Corentine, 

 Essequibo (Mazaruni, Cuyuni, Rupununi and other tributaries of the Esse- 

 quibo), Demarara, Berbice, by the Orinoco and its eastern and southern 

 tributaries, the Caroni, Caura, Ventuari and by the Rio Branco, and 

 the northern tributaries of the Amazon east of the Branco. 



The feature distinguishing this region is the known or reported connec- 

 tions between neighboring streams. The Cassiquiari connects the Orinoco 

 with the Rio Negro. The Atabapo is said during the rainy season to be 

 connected with the Guaina, and the Rupununi ol the Essequibo basin 

 with the Tacutu of the Rio Branco basin. It is said that the Essequibo 

 is also connected with the Rio Trombetas through the Apini and the 

 Oyapoc, Cachipur and Araguary with the tributaries of the Yari which 

 empties into the Amazon. 



The lower course of the Essequibo of British Guiana at least is con- 

 nected with the lower Orinoco by natural canals, so that these form part 

 of the Orinoco-Amazon-La Plata meshwork and contain the same types. 

 The Eastern Guianas (French) have a less varied fauna. 



The fauna of this region is of the greatest importance to theoretical chorol- 

 ogy, since this is one of the two old land-masses, and since it was by a 

 continuation of this area that South America is supposed to have been 

 connected with Africa. 



Our knowledge of the fish fauna of this region is derived from Miiller 

 & Troschel's account of the fishes of British Guiana ; Bleeker's Silure de 

 Surinam ; Vaillant's notes on the fishes of French Guiana, and his account 

 of the Berbice and the general work of Cuvier & Valenciennes, Giinther, 

 Eigenmann & Eigenmann, Regan and Pellegrin. 



