ioo THE KINGDOM OF MAN 



entirely upset previous notions, to the effect that these 

 are a primitive group, and has shown that their posses- 

 sion of only one replacing tooth is a retention of one 

 out of many such teeth (the germs of which are present), 

 as in placental mammals ; and further that many of 

 these marsupials have the nourishing outgrowth of the 

 foetus called the placenta fairly well developed, so that 



FIG. 19. 



Photograph of the skull of a male Okapi showing the paired boney 

 horn-cores similar to those of the Giraffe, but connected with the frontal 

 bones and not with the parietals as the horn-cores of Giraffes are. 



they must be regarded as a degenerate side-branch of 

 the placental mammals, and not as primitive fore- 

 runners of that dominant series. 



Speculations as to the ancestral connection of the 

 great group of vertebrates with other great groups have 

 been varied and ingenious ; but most naturalists are 

 now inclined to the view that it is a mistake to assume 



