THE LIMBS. 173 



a most reduced and almost, if not quite, function- 

 less condition, and sometimes even with completely 

 changed structure. 



From this point of view the muscles of the horse's 

 limbs form a most interesting study. It has been 

 truly said by Dr. G. E. Dobson,* that if no other 

 evidence were obtainable of his five-toed ancestors, 

 the condition of the muscles of the foot would suffi- 

 ciently indicate them. 



In the fore limb, where the ulna is represented 

 only by the olecranon (projection of the elbow) and 

 a greatly attenuated upper part of the shaft, and the 

 digits reduced to one, most of the forearm muscles 

 of the five-toed mammals are represented, the proper 

 extensor of the fifth digit (extensor minimi digiti) even 

 surviving, although both its insertion and special 

 function have been completely altered. In the hind 

 limb the two flexors of the toes (flexor digitorum lon- 

 gus and flexor hallucis longiis) are both present, with 

 well-developed tendons united in the foot as in the 

 great number of five-toed mammals. 



It must not, however, be supposed from what has 

 just been said that anything like all of the numerous 

 muscles that are developed in the hand of man, with 

 its versatile functions, can be traced in the horse. 



* " On the Comparative Variability of Bones and Muscles," 

 etc. Journal of Anatomy and Physiology, vol. xix. p. 16. 



