SPECIAL FEATURES IN STRUCTURE 



489 



connection with the marked difference in the position and general functions 

 of the fore extremities in each subject, is certainly more suggestive of evolu- 

 tion than of special design. Unless on the theory of evolution from remote 

 ancestors, it is indeed unintelligihle that all the bones of the carpus (wrist) 

 of man, conducing as they do to the greatest perfection of complicated 

 movements, should be represented in the same joint (knee) of the horse, 

 but so modified in their arrangement as to permit of no more than a simple 

 hinge-like motion, which is quite effectually provided for in other hinge- 

 joints by the adaptation of two bones only. And again, some of the digits 



Fig. 658. — Foot of Man and Foot of Horse Compared in Natural Positions 

 (Note position of ground surface in each case.) 



A, Tibia. B, Astragalus, c, Calcis. u. Scaphoid. E, Internal cuneiform. F, Splint-bone (a vestige of 

 2nd metatarsal). G, Cannon bone, or 3rd metatarsal. 1, 2, 3, Phalanges. 



of man, one of the five-fingered and five-toed mammals, are represented in 

 the horse by undeveloped structures or rudiments which serve no useful 

 purpose, as the horse walks on the tija of a single finger and a single toe; 

 in the foot of man, on the contrary, the whole of the bones from the ankle- 

 joint are brought into use, forming the plantar surface or sole. Such a 

 modification of structure in the lower animal can be understood only on 

 the assumption that it was the result of a gradual process of development 

 through which the five-toed foot of the horse's remote ancestors was in 

 course of ages transformed to the one-toed foot of the horse as we now 

 know it. A very pronounced series of changes it must be allowed, the true 

 character of which will be more easily understood by reference to figs. 

 658 and 659, taken by permission of the Eoyal Agricultural Society from 

 an article on the structure of the horse's foot by Professor Sir Geo. T. 

 Brown, and published in the Society's Journal, 1891. 



In fig. 658 both man and horse have the foot placed as it is in nature. 



