CANNON-BONES OF HIPPARION. 



339 



adoption of the one-toed method of progression, there was an 

 evident increase of speed. By examining Figs. 187 to 193, 

 we may see that the length of the bones below the fetlock, 

 compared to that of the cannon-bone, was greater in the 

 Hipparion than in the Anchitherium ; and in the horse, than 



km 



Fig. 203. — {After Gaud/y.) Cannon-bones of two iJiiiERENT Kinds 



OF Hipparion. 



in the Hipparion : length of pastern, as we have seen on p. 224, 

 being directly conducive to speed. Taking the converse of 

 this argument, which we may fairly do from our present 

 knowledge of palaeontology, we may assume that this increase 

 in the comparative length of the bones below the fetlock, is 



z 2 



