-52 ANNALS NEW YORK ACADEMY OF SCIENCES 



•divided into a northern and a southern part, i. e., Archiplata and Arch- 

 amazonia of von Ihering, and a connection appears to have existed be- 

 tween Guiana and Africa. 



There may be little reason to question the data of Professor Eigen- 



-mann, but there is, I believe,, much reason to question his interpretations. 

 The first conclusion, we believe, is to be accepted for the living affinities 

 of the South American fishes, but when we are dealing with their points 

 of family origin, we are in most cases concerned with ancestral forms 



" which have been dead for geological ages. In this case, the fossil record, 



■ scanty though it be, shows affinities between the living South American 



-and the fossil North American fishes. 25 a 



•Conclusion number two is also questionable, because : 



1. There is no geological support for the Archhelenis theory. This is 

 all the more true for the late Cretaceous, when the Cichlidse probably 

 originated. 



2. The point of origin and dispersal of the Cichlidse, as I propose to 

 show in the following pages, was not correctly determined. 



In the matter of his third conclusion, it should be said in Professor 

 Eigenmann's behalf that he did not then know that the Paraguay was not 

 connected with the Guapore and that the Sao Francisco was connected 

 with the Tocantins. He also did not know which waterfalls were not 

 barriers for fishes and that both the coastwise streams and the Alto Bio 

 Parana have more than double the number of species which he assigned 

 to them. 



In the same report, Professor Eigenmann also states that, of the number 

 of species of fishes, 60 per cent of the Guianan, 40 per cent of the Sao 

 Franciscan, 53 per cent of the Paraguayan, 30 per cent of the coastwise 

 ■streams of eastern Brazil, 42 per cent of Trinidad and 6 per cent of Cen- 

 tral American are Amazonian. In this static comparison, he has intro- 

 duced a probable source of error due to the environments when he draws 

 •conclusions from the above data. His lists include the fishes from the 

 ■entire basins of the coastwise streams, including Bio Sao Francisco, the 

 •entire Amazon basin and only the central and upper Paraguay Biver, 

 which is only one of the affluents of the great La Plata basin. If we com- 

 pare the massive Amazon with the entire basin of the coastwise streams, 

 is it not necessary to compare the entire La Plata basin and not only one 

 part, i. e., only one environmental complex ? For example, if we should 

 compare the fishes from Bio Sapao of the Bio Sao Francisco with those of 

 the mighty Amazon and its affluents, 100 per cent would be Amazonian 



^aSee H. F. Osboen : "The Age of Mammals." New York. 1910. 



