24 EVOLUTION 



arranged and convincing series in the museums 

 at Yale and New York without a thrill of 

 admiration at the wonderful reconstruction of 

 the ancient history of the noblest race of ani- 

 mals, and that most widely identified with man. 

 Since Huxley's day the fossil horse has been 

 "the cheval de bataille of the evolutionist." 



In spite of many puzzles, the pedigree is one 

 of the completest and most striking instances 

 of a well-preserved genealogical series. It 

 illustrates evolution, as it were, in process, for 

 the gradations are very gradual ; and natural 

 selection also, for the advances in the adapta- 

 tion of the limbs to swifter locomotion, of the 

 neck to reach the low grass, of the teeth for 

 more effective chewing, and so on, are all such 

 as may be reasonably interpreted in terms of 

 the selection of relatively better-fitted varia- 

 tions. Let us, since the case is a classic one, 

 attempt an outline of the geological history 

 of the horse family, following the careful 

 work of the successors of Marsh and Cope, 

 notably of Lull and Matthew. 



The horse-like animals probably sprang 

 from an extinct stock known as the Condyl- 

 arthra, which was first represented in Europe 

 and Asia, and afterwards in North America, 

 The Condylarthra had five toes on each foot 

 and a large part of the sole was on the ground. 



