HASEMAN, GEOGRAPHICAL DISTRIB UTION IN 80 UTH AMERICA 67 



It changes in the Guapore Eiver into A. paraguayensis, which is also 

 closely related to A. vittata. All of the species of this genus form a 

 natural group about A. teteramerus, excepting A. portal egrensis, and I 

 consider it as giving rise (or vice versa) to Cichlasoma bimaculatum. 



3. Heterogramma tceniatum can easily give rise to all of the species of 

 this genus. In fact, I have reasons to doubt the reality of all of these 

 species, because they may be nothing more than fluctuating variations, 

 principally in color, or somatic changes which may or may not be in- 

 herited. At any rate, there is an almost complete intergradation of all of 

 the species of this genus. Hence experimental work is needed before this 

 genus can be properly classified. 



4. There can be no doubt that CicMasoma bimaculatum is the most 

 primitive of its genus, because it is not well defined from /Equidens 

 portal egrensis, which is the most primitive living cichlid genus. 



5. I consider Creniciclila saxatilis as the most primitive of its genus. 

 It is represented in the south by C. lepidota. C. vittata is the southern 

 form of C. macro pthalmus, and they are connected by varieties through 

 C. lucius to saxatilis. C. joJmnna and the other elongate Amazonian 

 species of this genus also can be linked to C. saxatilis. 



I will not venture to discuss the relationship of the other genera and 

 species, because the results would be only an opinion with little or no 

 support. The above brief consideration, however, is extremely useful, 

 because Cichlasoma bimaculatum, 2Equidens teteramerus, Geophagus 

 brasiliensis and Creniciclila saxatilis are the generalized types which not 

 only are widely distributed but also have been the origin of the bulk of 

 the Cichlidas found in the various environmental complexes. The genus 

 Cichlasoma alone, according to Eigenmann, contains eighty-four of the 

 one hundred eighty-seven known species of American Cichlidas. These 

 four genera actually embrace at least 80 per cent of the species of the 

 American Cichlida?, and several other genera can easily be derived from 

 them. 



These four genera are found from one end of the Piano Alto to the 

 other, and consequently from their present distribution we can explain 

 the origin and distribution of their derivatives, but this has nothing to 

 do with the origin of the cichlid family. 



To sum up briefly, then, the distribution of the Cichlidae, we may say 

 that three highland genera are found in Eio Sao Francisco and have not 

 evolved any new species. The same three genera have produced nine 

 species in the Eio Grande do Sul, i. e., the three old plus six new species, 

 and six species in the Alto Eio Parana and the coastwise streams of east- 

 ern Brazil. Sixty per cent of the Paraguayan Cichlidas are also included 



