THE DARWINIAN THEORY OP EVOLUTION 



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variations which tend to fit a species into its environment are 

 passed on to the offspring and thus a new species will eventually 



m of Nut. History 



The earliest horse, the Eohippus, had four toes and the splint of the fifth toe on the fore- 

 foot. The Mesohippus had three toes with a rudimentary fourth toe. In the Merychippus, 

 only one toe reached the ground in walking. In the Hipparion one toe became greatly de- 

 veloped and the other toes became more rudimentary. The Pleistocene horse, Equus, and 

 the recent horse show this same characteristic. There were corresponding changes in the 

 fore-feet, skulls and sizes of the various horses. 



arise. Since these desirable variations are preserved by heredity, 

 each generation is better fitted to the environment than the pre- 

 ceding one. And so Darwin believed that through the passing 



