32 EVOLUTION 



Such cases of symmetrical three-toed develop- 

 ment may be fairly interpreted as reversions 

 to the ancestral type, and are to be distin- 

 guished from unsymmetrical extra toes, which 

 are mere duplications without ancestral in- 

 terest, and comparable to the occasional 

 occurrence of a sixth finger in man. 



In his very interesting study of " Wild Traits 

 in Tame Animals " (1897) Dr. Louis Robinson 

 refers to survivals of behaviour which date 

 from the old wild life in the open plains. It 

 was imperative long ago that the young foals 

 should run with their mothers, and to this 

 day they do not gorge themselves with milk 

 as calves do. When alarmed, horses hold 

 their heads high, as when wild upon the 

 plains; they bite very closely when grazing; 

 in both respects they differ markedly from 

 cattle. " Shying " is a relic of the instinct 

 of swerving suddenly from a suspicious rust- 

 ling and the like which used to mean the 

 presence of a lurking foe. Such survivals 

 are interesting and strike our fancy; but the 

 past lives in the present even more clearly 

 in regard to structure than in regard to habit. 

 and by the " button " at the lower end of the 

 splint bones the modern horse is indubitably 

 linked back to its polydactyl ancestors. 



CONNECTING LINKS. There is no more 



