THE ONE BIG DIGIT OF THE HORSE 245 



in its hand and foot. Each digit ends in what is supposed to have 

 been a small hoof, so that this little extinct animal would appear 

 to have been a five-hoofed mammal. It has the middle digit (the 

 iii.) of each limb enlarged. So there is evidence in support of 

 the possibility that this enlarged middle digit of Phmnacodus, or of 

 some animal like it, may have persisted in the innumerable 

 modifications which must have occurred, and have become the 

 ancestor of the solitary digit of the modern Horse. Indeed, the 

 evidence of the gradations from the former to the latter by gradual 

 loss of all the digits, excepting the middle one (the iii.), seems 

 complete and satisfactory. 



In Fig. 88, it will be seen that Pachynolophus had already lost 

 one of its Phoenacodal digits, viz., the big toe. Some weakness 

 of innervation and diminution of circulation in a part will lead to 

 disuse, and consequent dwindling, and eventual suppression. 



All the specimens in the Natural History Museum are being so 

 beautifully arranged that all who can read may learn. One thing 

 is wanted there — viz., a lecturing theatre, and some endowment left 

 by some rich person for lectures, to teach the people the great 

 philosophy of evolution. 



There are known several other allied extinct animals with a 

 hand and foot, probably derivable from some five-digited animal 

 like Phcenacodus, such as Hyracotherium venticolum, Palceotherium, 

 etc. 



Mr. Hutchinson ^ makes the following suggestion : ' One 

 cannot help sometimes wondering whether to some extent the 

 will of an animal may not be an important factor in evolution, 

 although it is the fashion to ignore it, and to attribute organic 

 changes to natural selection, or the " survival of the fittest." Mind 

 has a powerful influence over matter,^ and can we not conceive 



1 Creatures of Other Days, p. 214. ^ Yet the two are inseparable. 



