41 6 ZOOLOGY 



tural features ; thus the rodents, with modified teeth and 

 the canines lost, could not possibly give rise to carnivora, 

 primates, or artiodactyla. The artiodactyla and peris- 

 sodactyla, with their modified feet, could not be 

 ancestral to primates, carnivora, or rodents. Although 

 the details of evolution, and consequently of classifi- 

 cation, are to be determined only by minute and per- 

 sistent research, or may elude us altogether, many of 

 the broad features are so obvious that they may be 

 appreciated by any beginner. 



References 



FLOWER and LYDEKKER. Mammals, Living and Extinct. A. and C. Black. 

 OSBORN, H. F. The Age of Mammals. The Macmillan Company. 



