Text-fig. 2. 



mat. cap. 



Diagrams showing the development of the allantoic placenta in Perameles. 

 (a) 8hows the character of the preplacental maternal trophospongia with 



its lobules, between which vessels and glands penetrate. The capillaries 



ramify at the surface. 

 {h) Choiionic attachment has now taken place and the chorion has proli- 



