238 THE UROGENITAL SYSTEM 



spaces (Fig. 247). The ends of some of the villi are attached to the wall 

 of the decidua basalis and are known as the anchoring villi. In the con- 

 nective-tissue core of each villus are commonly two arteries and two veins 



Amnion 

 Chorion 



Uterine vessel 



Root of villus 



Sedionedvilli 



!;WifX : '/':'5 Spongy layer 

 / 



Muscular wall 

 of uterus 



i_ - ri ^r^ j ^^r-^Tiii i ' ' 



FIG. 246. Section through a normal placenta of seven months in situ (Minot). X 5. 



(branches of the umbilical vessels), cells like lymphocytes, and special 

 cells of Hofbauer, apparently undergoing degeneration. Lymphatics are 

 also present. The epithelium of the villi, as we have seen, is at first 



