66 ANNALS NEW YORK ACADEMY OF SCIENCES 



Crenicichla reticulata, Guiana, 



cyanonotus, 



lepidota, Guapore, 



saxatilis, to the north, 



lucius, Guiana, 



niacroptltalmus, Guapore, 



acutirostris, 



lenticulata, Guiana, 



strigata, 



cincta, 



Johanna, Venezuela, Guiana, Guapore, 



lugvibris, Venezuela, Guiana, Guapore, 



santeremensis, 

 Retroculus ladifer, 



Heterogramma taenia turn and a variety, Guapore, 

 agassizi, Guapore, 



trifasciatum and a variety, Guapore, 

 corumbw, Guapore, 

 Geophagus suHnamensis, Guapore, 



cupido, Essequibo, 



jurupari, Guapore, 



acuticeps. 

 Biotcecus opercularis, 

 Symphysodon discus, 

 Pterophyllum scalare. 



It may at first sight appear strange that the Amazon harbors so many 

 species and genera of Cichlidas, but it is exactly what one would expect 

 because of its vast size and tropical location. Of these fifty-three species, 

 at least twenty-two are found in Eio Cluapore, and of these twenty-two, 

 twelve are not found in the Paraguay. This fact alone is sufficient to 

 disprove any wholesale exchange of fishes between the Paraguay and the 

 Guapore. Prom the standpoint of phylogeny, I am able to throw a little 

 light on the above distribution of the Cichlidge. These conclusions were 

 derived from both the field and laboratory, and inasmuch as the purely 

 systematic data have already been published by Pellegrin, Eegan and 

 more recently by myself, I will not repeat them. 



1. I consider Geophagus urasiliensis as the most primitive of the living 

 members of this genus. It is interesting to note that this species is not 

 found in the Amazon and that its nearest northern ally is Geophagus 

 steindaclcneri, which was originally described by Steindachner as Geophar 

 gus brasiliensis from Eio Magdalena, which, like the coastwise streams 

 of southeastern Brazil, flows out of Archean mountains and possesses 

 therefore remarkably similar environments. 



2. 2E guldens teteramerus appears to be the most primitive of its genus. 



