A CONCLUSIVE INSTANCE 61 



and of the leg complete and separate, and which possessed 

 forty-four teeth, among which the crowns of the incisors 

 and grinders had a simple structure ; while the latter 

 gradually increased in size from before backwards, at any 

 rate in the anterior part of the series, and had short 

 crowns. And if the horse has been thus evolved, and the 

 remains of the different stages of its evolution have been 

 preserved, they ought to present us with a series of forms 

 in which the number of the digits becomes reduced ; the 

 bones of the forearm and leg gradually take on the equine 

 condition ; and the form and arrangement of the teeth 

 successively approximate to those which obtain in existing 

 horses. 



Surely any unprejudiced student will be prepared 

 to regard as a conclusive instance the actual demon- 

 stration of these intermediate forms. This, and no 

 less, has actually been accomplished. 



The remains of the horse found in European cave 

 deposits and gravels give us no help. Their charac- 

 ters are indistinguishable from those of the horse we 

 know. In earlier deposits, in Europe and India, we 

 come upon remains which cannot be denied equine 

 rank, but in which there are two small digits, one on 

 each side of the central digit. These lateral digits 

 do not touch the ground. This extinct horse, or 

 ancestor of the horse, is known as Hipjiarion. 

 Before him there was another animal, now known 

 as Anchitherium, which possessed three complete 

 toes, all of which touched the ground, and were 

 doubtless of actual use. This European sequence, 

 Anchitherium, Hipparion, Equus, is very suggestive 

 indeed, especially when we take into account various 

 other skeletal and dental characters which I cannot 

 detail here. It seemed suggestive to Huxley, and 



