PREGNANCY 



65 



Amniotic cavity 



Body-stalk 

 Allan to is 



Archenteron 



Chorion 



Amniotic cavity 

 Embryo 



Body-stalk 



Placental 

 villi of chorion 



Allantois 



Yolk-sac 



Chorion 



Heart 



Fig, 4*2. — Diagram showing the early formation of the allantois. 



(From Gnufs Anatortuj.) 



Fig. 43. — Diagram showing a later stage in the development of the 



allantois. (From Grojj^s A/iatom//.) 



Placental villi 



Di<jet<tire 

 tube 



, Fore-gut 

 Embryo 

 A mniotic cavity 



Embryo 

 Amniotic cavitv 



Fig. 44. — Diagram showing the expansion of the amnion. 



(From Orof/s Anatom//.) 



Fig. 45. — Diagram showing a later stage in the development of the 



umbilical cord. (From Groj/'s Anatom//.) 



5 



