JEvolution of the Earth. 



h c d e f 



99 



Equus : Qua- 

 ternary and 

 Recent. 



Orohippus 

 Eocene. 



DiAORAM illustratinp: the prradual evolutinn of tlie horse-fainily (after Yro- 

 fessor Mai-sli\— kindly furnislied by Messrs. 1). Ajiplet^n & Co. Throughout 

 the series, a indicates fore-foot ; h, liind-foot; r, fore-ami; (/, shank; f, molar, 

 side-view; f and <i, grinding surface of upper and lower molars. The Eohip- 

 pus of the Lower Eocene, and the Phenacodus (Cope), are not represented in 

 this (liaj:r;ini. 



