=94 



EVOLUTION OF 2 HE HORSE. 



Still less SO than in the horse ; and, consequently, that there 

 must have been a certain amount of lateral play in them. 

 The 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 

 generally 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 the fetlock pad (p. 197) is liable to come down on the 



Uri 



Fig i^T— {After Gauchy.) FORF 

 Foot of Paloploiherium (Jrd 

 real lengtli). 



Flo ^U --{After Gmuhy) Lebi 

 Front Foot or Orohippus 

 Aguis (fullisize). 



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 on 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 

 (Fig. 128). Hence, I am inclined to think that the Hip- 

 parion, whose immediate ancestors were digitigrade animals, 

 used the second and fourth digits, at least of its fore feet, 

 to some extent at fast paces ; if not in slow movement. 

 Still earlier, we find in the middle Eocene age the 



