320 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



Unfortunately little is known of the fauna of the streams of the table 

 land of Guiana, the region where the remnant of the original fauna may 

 be expected to persist. Schomburgk's collections made in these streams 

 were largely lost. He states that it was rich in species (over 30). 



Andre ("A Naturalist in the Guianas," p. 205) says : " In fact the falls of 

 Para [of the Caura] appear to constitute an effective barrier between dis- 

 tinct forms of river life," and that the fauna above the falls is different 

 from that below. 



The most promising field for scientific results, if not number of species, 

 seems to me to be offered by the rivers of this region, which should be 

 explored above and below falls that are impassable barriers for the ascent 

 of fishes. 



The rivers of this region, exclusive of the northern tributaries of the 

 Amazon, concerning which not much is known, contain a total of about 

 298 recorded species. Of these about 60 per cent, are also found in the 

 Amazon; as of these about 16 species are from the Rio Branco basin and 

 not from the other streams and the Rio Branco belongs to the Amazon 

 system, this number must be reduced by 16, which still leaves over 50 

 per cent, of the fauna identical with that of the Amazon. 



List of Guiana Fishes with their Known Distribution. 



In the following list the letter A indicates that the species has been re- 

 corded from the Amazon. L indicates that the species has been recorded 

 from the La Plata, S that the genus is also found in the San Francisco, 

 * that the species is peculiar to the province, ** that the genus is peculiar 

 to the province. 



