S/epAos Yq 



S^eooc/ofi /% 



Mastodon ^/q 



RECENT 



PLEISTOCENE 



UPPER PLIOCENE}] 



lOmPl/OCENE 

 UPPER MIOCENE ) 



TflDOLE M/OCENE \ 



Hi(jrotion into I Gompholherium 



North Amnca [/on^ chm), 



Tetrabelodon 'M ^01^^^ M/OCENE I 



GomphoTf)Cr/um 

 . /on^irostrib btaoe 

 (■ihorfeni/Ki 

 C/v'n) 



UPPER OLIGOCENB 



LOyEROUGXENE 



Paloeoma^todon 'fy UPPER EOCENE 



ro/aeOmastodon 

 {/e/io/Mn/fio c/iln) 



MoerifJier/um /^ 



2 



Moerilhenum 

 MWOLE EOCENE 1 {shor/cfim) 



I O/VfR £OCfA/f (ancestor urrAnoyyr(). 



2 



Fig. 169. — The evolution of the elephants: On the right the skulls, with the pro- 

 boscis restored in black; on the left the last lower molar. The principal changes 

 lie in the increased height of the skull and its decreased length with a consequent 

 reduction in number of teeth, also in the development of a long snout or trunk and 

 in the increased length of two or four incisors into tusks. (Tetrabelodon should 

 read Gomphotherium.) (From Scott, after Lull, modified by Sinclair.) 

 (388) 



