THE CHARACIDAE. 31 



Tropical American fishes. They (Proc. U. S. N. M., 14, 15) considered and 

 summarized the distribution of the genera and species so far as known. They 

 recognized sixty-five genera and about four hundred and sixty species, as com- 

 pared with the forty genera and one hundred and eighty-one species enumer- 

 ated by Gunther (1864). It is not necessary to give here the details of the 

 results of their inquiry into the geographical distribution of the species. It 

 was found that nineteen of the genera recognized were distributed over the 

 entire eastern slope of South America and that five of these had representatives 

 in the La Plata and the Amazon, but not in the small rivers emptying into 

 the Atlantic in southeastern Brazil. One genus, Saccodon, was confined to the 

 Pacific slope. Twenty-seven genera were limited to the Amazons, or to the 

 Amazons and the region north of it. The Guianas held two peculiar genera, 

 the Rio Magdalena one, the southeastern coast streams one, while four genera 

 had a wide but irregular distribution. 



Many modifications in these summaries of distribution are necessary, 

 both on account of the changes in the boundaries of the genera, and owing to 

 the increase in our knowledge of the distribution of the several species. The 

 papers published since the enumeration of 1891 and 1892 have dealt largely 

 with the fauna of Paraguay, Rio Grande do Sul, Guiana, Colombia, and Mexico 

 at nearly opposite ends of the range of the family and with the fauna of the 

 Pacific slope of Ecuador. 1 A reconsideration of the entire problem of the dis- 

 tribution of the fresh-water fishes of South America may be found in The fresh 

 water fishes of Patagonia and an examination of the Archiplata-Archhelenis 

 theory. (Reports of the Princeton university expeditions to Patagonia, 1909, 

 3, p. 225-374. Catalogue of the fresh-water fishes of tropical and south tem- 

 perate America. Ibid., 1910, 3, p. 375-512. 



1 While no attempt has been made to trace the details of the evolution of our knowledge of the 

 African Characins the present account would be most inadequate and incomplete without reference to 

 Boulenger's work on the Characins of the Congo and Nile Basins. The new genera and species from 

 the Congo were described for the most part in volume 1 and 2 of the Annales Musee du Congo. A general 

 account in which all the species were considered, formed part of his Les poissons du basin du Congo, 

 1901. The Nile representatives are described and figured in his superb volume, The fishes of the Nile, 

 1907. Among other recent authors on the African Characins is J. Pellegrin, who is describing the 

 material of the Paris Museum. Finally Boulenger (Catalogue of the fresh-water fishes of Africa, 1909, 

 1, p. 174-298) redefines the subfamilies and genera and redescribes all of the African species. He recog- 

 nizes twenty genera and one hundred species. 



