248 STUDIES IN THE EVOLUTION OF ANIMALS 



which is not permanent might be dispensed with as advantageously 

 as the two suppressed digits of the Horse ! 



The reader might say that from the series of limbs shown in 

 Fig. 88 it is clear that the one digit of the Horse is derived from the 

 big middle digit of some animal like Phcenocodus. Suppression of 

 parts is seen to be such a common phenomenon in the process of 

 evolution throughout the animal kingdom, nay, throughout the 

 whole of what we call living nature, that it is the most rational 

 conclusion to come to. Allied animals had five digits, therefore 

 those that have less have lost some by suppression. 



With reference to the evolution of the Horse, as evidenced by 

 the feet of the fossil forms of the Horse tribe, Dr. Alfred Russel 

 Wallace 1 writes : * Well may Professor Huxley say that this is 

 demonstrative evidence of evolution ; the doctrine resting upon 

 exactly as secure a foundation as the Copernican theory of the 

 motions of the heavenly bodies at the time of its promulgation. 

 Both have the same basis the coincidence of the observed facts 

 with the theoretical requirements.' 



There can be no doubt about the evolution of the Horse from 

 some such ancient form as that of the Eohippus. The question 

 in this discussion is restricted to the origin of the big digit in the 

 whole series, that is, whether it was originally one digit, or a fusion 

 of two. 



I might perhaps say that I do not dispute that the origin of the 

 existing Horse's digit is as stated, but I would now ask Are we 

 so ' cocksure ' that Ph&rtacodus is to be credited with only five 

 digits, instead of sixt 



I confess it seems preposterous to ask such a question as this, 

 when there is more than abundant evidence to show that our own 

 hand and foot, like those of so many mammals, are formed on the 



1 Darwinism, p. 389, 



