328 



EVOLUTION OF THE HORSE. 



length, also, of the side digits would lead us to form the 

 opinion that this animal walked on three toes. 



The majority of palaeontologists, I believe, consider that 

 the Hipparion used only one toe of each foot in progression. 

 Against this opinion I may advance the fact, not very gene- 

 rally known, that some horses, especially high-caste Arabs, 

 have such a naturally large amount of " play " in the fetlock 

 and pastern joints of the fore legs, that during the fast gallop. 



Fig. 194. — {After Gaiidry.) FoRE 

 Foot of Paloplotherium (|rd 

 real length). 



Fig. 195. — {Aftzr Gatidry.) Left 

 Front Foot of Orohippus 

 Agilis (full size). 



the fetlock pad {see p. 221) is liable to come down on the 

 ground and get bruised. The ergot, which is in the centre 

 of this pad, is evidently, as pointed out by Sir William 

 Flower, the rudiment of a structure (like the pad of a dog's 

 or cat's foot) that acted as a buffer to the fetlock at the time 

 when the horse was a digitigrade animal, namely, one which 

 walks oil its digits, and not as the horse now does in unguli- 

 grade fashion, only on their tips. In all horses which have 

 free action, the fetlock descends a good deal in the gallop 



