THE PLACENTA, 

 FIG. 257. 



667 



Series of diagrams representing the relationship of the decidua to the 

 ovum at different periods. The decidua are colored black, and the ovum is 

 shaded transversely. In 4 and 5 the vascular processes of the chorion are 

 figured (copied from Dalton). 1. Ovum entering the congested mucous 

 membrane of the fundus decidua serotina. 2. Decidua reflexa growing 

 round the ovum. 3. Completion of the decidua around the ovum. 4. Gen- 

 eral growth of villi of the chorion. 5. Special growth of villi at placental 

 attachment, and atrophy of the rest. 



