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I'HE 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)y is that portion of the uterine mucous membrane 

 which coats the internal surface of the uterus wherever the 



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

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

 c, chorion; </, placenta; d\ remains of tufts on the smooth chorion;/, de- 

 cidtia reflexa (inner) ; </, decidtia vera (outer). (After Bernhard Schultze.) 



latter is not attached to the placenta. The placental or 

 spongy deciduous membrane {d. jplacentalis or serotina^ 

 Fig. 198j_^Zt^5 Fig. 200, d) is simply the maternal placenta 



