THE FCETAL MEMBRANES OF MAN. 



257 



is very difficult, but occasionally it may still be accomplished to some 

 extent. 



Moreover in later months the inside of the decidua reflexa is 

 firmly fused with the chorion, and since the chorion in its turn is in 

 contact with the amnion (fig. 147 ch and am), one now comes, by 



Fig. 148. Section through decidua serotina (Dse) at the transition into decidua vera (Dv) and 

 reflexa (Dr), after KUSDRAT USD EXGELMANX. 



M, Musculature of the uterus ; Sp, spongy layer of the decidua vera and serotina ; C, compact 

 layer of the same ; glu, uterine glands ; sp. fissures in the serotina resulting from growth 

 of the glands ; dh, ampullarial spaces in the spongy layer produced by growth of the glands. 



cutting through the muscular wall of the uterus, and then opening 

 the foetal membranes, .which are thus pressed together, directly into 

 the amniotic cavity, in which the embryo lies bathed in the amniotic 

 fluid. 



(3) The third region of the uterine mucous membrane, or the 

 decidua serotina (fig. 148 Dse), is that part which joins with the 



17 



