382 Evolution and Distribution of Fishes 



The structurally primitive members of the family make 

 exact and easy connection with the rather primitive Centrar- 

 chidae. And it is specially interesting here to note that, 

 while the two families in part differ in that the latter have, 

 and the former are devoid of vomerine teeth, the only fossil 

 cichlid genus Priscacara from Lower Eocene freshwater 

 strata, is described by Cope as having these. The family 

 also resembles the more primitive percoids and the simpler 

 serranids in having a continuous dorsal fin, and this char- 

 acter is seen in Priscacara. Rarely here, as in the genus 

 Cichla, is there a tendency shown toward division of the 

 dorsal fin into an anterior spinous-rayed, and posterior soft- 

 rayed part. The family then probably evolved from some 

 annectant type between primitive members of the Centrar- 

 chidae, Percidae, and freshwater Serranidae. 



We would also place the area for origin of the group 

 in the central or southwestern United States, and here 

 Priscacara was native during early Eocene times. But 

 already probably, and almost certainly, during the mid or 

 late Cretaceous period, migrant as well as evolving genera 

 had passed into S. America, and there peopled the lakes 

 and rivers with numerous representatives, whose descend- 

 ants are now seen in the nearly 150 species native to the 

 northern part of that continent. Then migrating across 

 the S. Atlantis bridge they reached the W. African coast, 

 and spreading eastward — as did quite a number of other 

 families^they gave rise in time to the 150 species that are 

 now found there, and which have constituted one of the chief 

 features in the great "Tanganyika Problem." Passing to 

 the south-east coast and also down the Nile, they advanced 

 by the former line of migration through Madagascar along 

 the Indo-Mascarene bridge to India and Ceylon, where 

 they are now represented by three species. 



The writer would refrain from such direct assertion as 

 is contained in the above paragraphs, did he not fully believe 

 that this exactly fits the facts of the case, and even more 

 fits many similar cases already referred to, or to be cited in 

 later context. But the group of the Cichlidae forms a very 

 natural assemblage over three continents, that has at the 

 same time no marine representatives. For while the marine 



