388 



DARWINISM 



CHAP. 



Fore- 

 foot. 



EBCENT. 

 Equus. 



PLIOCENE. 

 Pliohippus. 



Protohippus 



(^Hipparion). 



MIOCENE. 



Miohippus 

 {Anchitherium). 



Mesohippus. 



Hind- 

 foot. 



Fore- 



Leg. Upper molar. Lower molar. 



EOCENE. 

 Orohippus. 



Fig. 83.— Geological development ot the horse tribe (Eohippus since discovered). 



