1 66 



THE EVOLUTION OF MAN. 



deciduous membrane; these parts may be called the outer, 

 the inner, and the placental deciduous membrane. The 

 outer or true membrane {d. externa or vera, Fig. 198, dv, 

 Fig. 200, g), is that portion of the uterine mucous membrane 

 wliich coats the internal surface of the uterus wherever the 



z d 



Fig. 200. — Human embryo, twelve weeks old, with its coverinjrs ; natural 

 size. The navel cord passes from the navel to the placenta : 6, amnion ; 

 c, chorion; d, placenta; c?', remains of tufts on the smooth chorion;/, dc- 

 cidua refiexa (inner) ; g, decidua vera (outer). (After Bernbard Schultze.) 



latter is not attached to the placenta. The placental or 

 spongy deciduous membrane {d. placentcdis or serotina, 

 Fig. 198,j9Z?^5 Fig. 200, d) is simply the maternal placenta 



