ELEPHANTS, HORSES, AND CAMELS 



185 



That we can see relationship in hving forms, particularly relation- 

 ship which can be interpreted only on the basis of common deriva- 



EVOLUTION OF THE CAMELS 



g 



CD 



s 



Pleistocene 



I 





fe 



;3i 





Recent 



Pliocene 



Miocene 



Auchenia 

 (Llama) 



Skull 



Feet 



Procamelus 



Poebrotheriixm 



Oligocene 



Eocene 



Protylopus 



Teeth 



Mesozoic or Age of Reptiles 



Hjjpotheticol five-toed Ancestor 



Fig. 110. — Evolution of the camels, as indicated by the skull, feet, and teeth. 



(From Lull, modified after Scott.) 



tion, is conclusive in itself, but the discovery of actual n^nains of 

 creatures now extinct in such series as these admits of no other 



