652 



REPRODUCTION. 



over the surface of the egg. At last they come in contact and unite 

 with each other, forming a kind t?f cicatrix, which remains for a time, 

 to mark the situation of the original opening. 



When the development of the uterus has reached this point (Fig. 



FIG. 204. 



FIG. 205. 



IMPREGNATED UTERUS; showing formation of 

 decidua. The decidua is represented in 

 black ; and the egg is seen, at the fundus of 

 the uterus, engaged between two of its pro- 

 jecting folds. 



IMPREGNATED UTERUS, with folds of decidua 

 growing up around the egg. The narrow 

 opening, where the folds approach each 

 other, is seen over the most prominent 

 portion of the egg. 



FIG. 206. 



206), the egg is completely enclosed ; being covered with a decidual 

 layer of new formation, by which it is concealed from view when the 

 uterine cavity is laid open. This newly-formed 

 layer, enveloping the projecting portion of the 

 egg, is called the Decidua reflexa ; because 

 it is reflected over the egg from the general 

 surface of the uterine mucous membrane. The 

 orifices of the uterine tubules, in consequence 

 of the manner in which the decidua reflexa 

 is formed, are seen not only on its external 

 surface, or that which looks toward the cavity 

 of the uterus, but also on its internal surface, 

 or that which looks toward the egg. 



The decidua vera, therefore, is the original 

 mucous membrane of the uterus. The decidua 

 reflexa is a new formation, which grows up 

 around the egg, to enclose it in a distinct 

 cavity. 



If abortion occur at this time, the mucous membrane of the uterus, 

 that is, the decidua vera, is thrown off, and brings with it the egg and 

 the decidua reflexa. On examining the mass so discharged, the egg 

 will be found imbedded in the decidual membrane. One side of the 

 membrane, where it has been torn away from the uterus, is ragged ; 

 the other side, corresponding to the uterine cavity, is smooth or gently 

 convoluted, and exhibits distinctly the orifices of the uterine tubules^ 

 while the egg itself can only be extracted by cutting through the decid- 



IMPREGNATED UTERUS; show- 

 ing the egg completely en- 

 closed by the decidua reflexa. 



