OUR FACE FROM FISH TO MAN 



its modern relative that we can actuallj'^ fit the 

 contours of the fossil opossum skull fragments 

 into the skull of a recent opossum with very little 

 adjustment of the latter; so that we may safely 

 study the lowly 'possum as a representative and 



^^--'^7-'^>j^rj>>-. 



Fig. 27. Skull Parts of Extinct Opossum, Superposed on 

 Outlines of Skull of Recent Opossum. 



For details, see p. xvii. 



descendant of the pouched mammals of the latter 

 part of the Age of Reptiles. 



Even the modern opossum skull is at first sight 

 strangely similar to that of one of the mammal- 

 like reptiles of the far-off Triassic. It will easily 

 be seen from Fig. 28 that the opossum, like any 

 primitive mammal, has inherited the entire ground- 

 plan of its skull from its progressive reptilian 



ancestor. Considering the great advance in gen- 



48 



