THE NEW EVOLUTION ^^^ 



remained wholly separate, as far back at the very least 

 as the beginning of the Pleistocene. 



This is important, for in the case of the horses the 

 various types found in the Pleistocene, though numer- 

 ous and varied, were all of the modern type, and the 

 same is true in the case of other mammalian forms. 

 So it is possible to assume that the developmental 

 history of man has run parallel to the developmental 

 history of other mammalian lines, as would naturally 

 be expected. 



What, then, was the connection between man and 

 the other mammals, and when did man branch off 

 from the Primate stock? 



Professor Osborn has pointed out that the geo- 

 logical period in which the various lines of mam- 

 malian development separated and radiated from each 

 other was the Eocene. "Even in Lower Eocene time 

 all the existing families of hoofed mammals, such as 

 the horses, tapirs, rhinoceroses and titanotheres (the 

 last all now extinct) had widely separated from each 

 other in tooth, limb, hand and foot structure. Be- 

 fore the close of Eocene time these branches were 

 further subdivided into forest-loving and plateau- 

 loving types; in every branch the forest-loving types 

 were stationary or regressive. Similarly, by the 

 close of Eocene time the mastodont and elephant 

 families are found widely separated into five greater 

 branches (in Oligocene time there were numerous 

 sub-branches and in Miocene time eighteen distinct 

 branches). In the succeeding Oligocene time we 



discover a sharp and world-wide division between 



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