4o6 Evolution and Distribution of Fishes 



or across S. E. Arabia and Persia where more recent ob- 

 literation of them has happened. Scarcely anything favors 

 the latter, nearly every fact favors the former view. But 

 further while marine deposits of Cretaceous and Tertiary 

 age are met with from Mozambique northward along the 

 African and Arabian coasts, continuity from Central East 

 Africa to Madagascar and India seems to have persisted 

 well into Eocene or even Oligocene times. If then the 

 head-water areas of the Zambesi, the Nile, the Congo, and 

 the Ogowe formed a common distributional region during 

 late Eocene and Oligocene time, and were connected east- 

 ward through S. Mozambique and Madagascar to India, 

 such would wholly explain the present distribution. 



The Cichlidae and related groups might next concern 

 us. In the last chapter evidence was adduced to show that 

 the Cichlidae, Pomacentridae, Labridae, and Scaridae form 

 a progressive and specializing series, that start with primi- 

 tive Cichlids. A chart of their present distribution is given 

 on page 381. We learn then that 140 species of Cichlids 

 extend from the southern United States and Cuba to 

 Central South America; that 150 species have spread over 

 Africa and Madagascar, while three only occur in S. India. 

 But further, as before noted (p. 382) Cope has discovered 

 seven species of Priscacara from the Green River and 

 MantI Shales of the Western States, that show at least 

 some primitive characters compared with existing species. 

 The possible relation of these then to ancient North Ameri- 

 can Percidae or Centrarchidae will be returned to later. 

 Here is not only again suggested a direct connection from 

 S. E. Africa to India, but even an extensive S. American- 

 African bridge of Eocene to early Oligocene date. 



But some brakish-water species of Cichlids that lived 

 increasingly on hard-shelled molluscs and crustaceans evi- 

 dently passed outward from the rivers of Western N. 

 America, of Central and South America, as well as along 

 the coastal line of the American-African bridge, and there 

 lurking among rocks or coral reefs, had the teeth con- 

 densed and the pharyngeal bones fused. Later by pro- 

 environal and selective action, as a hard-shell diet became 

 frequent, these had the body condensed in mechanical re- 



