Ill LECTURES ON EVOLUTION 127 



All who have occupied themselves with the 

 structure of Anchitlierium, from Cuvier onwards, 

 have acknowledged its many points of likeness to 

 a well-known genus of extinct Eocene mammals, 

 Palceotherium. Indeed, as we have seen, Cuvier 

 regarded his remains of Anchitherium as those 

 of a species of Palceotlierium. Hence, in attempt- 

 ing to trace the pedigree of the horse beyond 

 the Miocene epoch and the Anchitheroid form, 

 I naturally sought among the various species of 

 Palaeotheroid animals for its nearest ally, and I 

 was led to conclude that the Palceotlierium minus 

 (Plagiolophus) represented the next step more 

 nearly than any form then known. 



I think that this opinion was fully justifiable ; 

 but the progress of investigation has thrown an 

 unexpected light on the question, and has brought 

 us much nearer than could have been anticipated 

 to a knowledge of the true series of the progeni- 

 tors of the horse. 



You are all aware that, when your country 

 was first discovered by Europeans, there were no 

 traces of the existence of the horse in any part 

 of the American Continent. The accounts of the 

 conquest of Mexico dwell upon the astonishment 

 of the natives of that country when they first 

 became acquainted with that astounding pheno- 

 menon a man seated upon a horse. Neverthe- 

 less, the investigations of American geologists 

 have proved that the remains of horses occur in 



