246 



THE WOKLD OF LIFE 



Recenl 



Pleistocene ELE PHA3 



( short chinj 

 Ufiper Pliocene 



Lower Pliocene 

 Upjier Miocene 



TETRABELODON 



[LONGIROSTRrS STACE] 



(shortening chinj 



Middle Miocene TETRABELODON 



fANCUSTTDENS STAGE] 



lower Miocene (long chinj 



l/frper Oligocene 



Migration from Africa 

 into EuTvp.e -Asia 



Imer Oligocene? 

 Upfier Eocene 

 MiddleBocene 

 Lower Eocene 



PALAEOMASTODON 

 ^lengthening chinj 



MOERlTHEKrUM 

 (short chin) 



Fig. 82. — Diagrams showing Increase of Size and Alteration in Form of 

 Skull and Teeth of the Proboscidea since Eocene Time. (B.M. Guide.) 



