THE ANCESTRY OF THE VERTEBRATES 509 



From this typical vertebra Owen was able to explain the 

 skeletal elements in each segment of the body in every verte- 

 brate, and was thus able to construct the skeleton of an Arche- 





FIG. 138. Owen's interpretation of mammalian skulls. [After OWEN.] 



(A) Generalized mammal. (B) Man. For explanation see accompanying 

 table given in text. 



type, which consisted of a series of such vertebrae gradually 

 tapering and losing their characteristic features in the caudal 



