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COPE 



:s^- 





V- 



Of the superfamilies which continue to the present day 

 the existing species are few in number, with the exception, 

 of the Booidea. All except the Booidea are now restricted 

 to tropical and subtropical regions, and while the majority 

 of Booidea have the same distribution, there are many 

 species m temperate regions, and a few dwell within the- 

 Arctic Circle. 



The above table includes only the most important of the- 

 superfamilies of the Diplarthra. Those of the Perissodac- 

 tyla are equally distributed on both sides of the Northern 

 Hemisphere, but only modern forms of the Equoidea appear- 

 in South America and in late Neocene time. Pantolestoi- 

 dea have been so far found in North America only and 

 the other superfamilies are relatively rare in that continent 

 except the Cameloidea, which are more abundant than in, 

 the Old World. This and the Booidea only appear in South, 

 America m the late Neocene. 



As in the Perissodactyla there is a reduction of the digits. 



