2 FRESH-WATER FISHES OF SOUTH AMERICA — EIGEXMANN. 

 EXTENT OF THE SOUTH AMERICAN FRESH-WATER FAUNA. 



There are far more fresh- water fishes iu the neotropical thau in auy 

 other region.^ Complete euumeratious of the fresh- water fishes of other 

 continents are rare, but the following comparison of the latest lists of 

 European and Xorth American fresh-water fishes with a list of the 

 South American species will show the extent of the South American 

 fauna. Those families which are marine, but whose species enter fresh 

 waters, are marked with an asterisk (*). 



•Heilprin (Distribution of Animals. International Scientific Series D, Appleton 

 & Co., 1887, p. 79) says: "The fresh-water fishes of the Neotropical realm are spe- 

 cifically more numerous tliau those of any other region, with perhaps tlie exception 

 of the Holarclic." The Holarctic is defined as follows (p. oQ) : "The Palaearctic and 

 Nearctic tracts, in the absence of both positive and negative faunal characters of 

 sufficient importance to separate them from each other, are indisputably linked to- 

 gether, and should constitute but a single region (the Holarctic)." Leaving out of 

 consideration all animals but fishes, there art^ certainly both negative and positive 

 characters to separate the Fahearctic and Nearctic. Mr. Heilprin enumerates the 

 following peculiarities as separating the Nearctic from the Pahtarctic : The presence 

 in the Nearctic of Cafostomidw, Centrarchidce, dmiatidw, Lepidosieidce. To these should 

 be added the Hlodontldm, Percopsidw, AmhUfopsidK, Aphredoderidie, Elassomaiidcf, 

 and the peculiar development of the Percidip. From an ichthyological standpoint 

 there are certainly positive characters sufficient to separate the Neaictic from the 

 Palaearctic. 



