48 



ELEPHANTS. 



functional hind limb. In many points they resemble Moeri- 

 therium, as, for instance, in the form of the brain, teeth, and 

 pelvis ; and it seems likely that both they and Moeritherium 

 had a common ancestor in Lower Eocene times. It was pro- 

 bably a swamp-living creature, some of whose descendants 

 became gradually more and more exclusively aquatic in their 

 habits, thus giving rise to the Sirenia, while others became 

 exclusively terrestrial and gave rise to the elephants as described 

 above. 



TABLE SHOWING THE RIDGE-FORMULA OF THE TRUE MOLARS IN THE 

 APPROXIMATE LlNE OF DESCENT OF THE ELEPHANTS FROM 

 Moeritherium. 



A series of specimens illustrating the gradual increase in the 

 number of ridges on the molars is shown in Table-case 24. 



Printed by TAYLOR and FRANCIS, Red Lion Court, Fleet Street. 



