HASEMAN, GEOGRAPHICAL DISTRIBUTION IN SOUTH AMERICA 51 



of the genera are found in the Amazon valley, we have yet absolutely no 

 evidence that the ancestral Cichlidse originated in the Amazon. In fact, 

 as Matthew has already pointed out, the presence of a large number of 

 species in a given locality is no evidence as to their point of family origin. 

 Indeed, neither the genus nor the family need have originated there, since, 

 as Matthew has shown, the point of origin is apt to be the first place of 

 extinction. We may note, therefore, that the above rules which have been 

 used to determine the point of origin of any group of animals have only a 

 limited application. 



So far, there have been only a few specialists interested in the ichthy- 

 ology of South America. Of these, Professor Eigenmann has certainly 

 given us the best treatise on the distribution of the fishes. In fact, his 

 publications are the only ones which deal in a comprehensive way with 

 the great mass of these fishes, including as they do almost two thousand 

 species. 



In the problems of the origin and dispersal of Cichlidse and Characinidse, 

 Professor Eigenmann (1906) has given interesting data. He has prepared 

 a hypothetical map which indicates that the Cichlidse dispersed from east- 

 ern Guiana and the Characinidae from the Amazon. This conclusion ap- 

 pears to be based on the fact that the most of the genera of Cichlidse and 

 Characinidse are found in these regions. As I have already stated, how- 

 ever, this is no evidence for the point of origin and subsequent dispersal 

 of a family of animals. If it is, we might erroneously conclude from the 

 present distribution that the deer and tapir originated in the state of 

 Matto G-rosso, Brazil, and the camel in the Ancles, because more of the 

 species are found there ; but in these latter cases, paleontology has shown 

 that the first point of origin was in the northern hemisphere, where the 

 species no longer exist. I hope to show in the following pages that the 

 point of origin of many species and genera of living Cichlidse has been in 

 the Amazon, but that the point of origin of the ancestral Cichlidse was 

 not in South America. 



In another paper, Professor Eigenmann draws the following conclu- 

 sions in his extended discussion of the distribution of the South American 

 fishes : 



1. The fishes of South America exhibit no close affinity with those of 

 North America. 



2. The South American fishes, certainly the Characinidse and Cichlidse, 

 lend support to the Archhelenis theory. 



3. The fishes of the coastwise streams of eastern Brazil differ more 

 widely from the Amazonian than do the Paraguayan. 



1. The distribution of the fishes indicates that South America was 



