PLATE Y. 
Fig. 5. Section of a Portion of the Wall of the Blastocyst, showing cyto-trophoblast and 
plasmodi-trophoblast, with portions of decidua, and the opening of an enlarged sinus¬ 
like capillary into the implantation cavity. x 350 d. cyt., cyto-trophoblast; dec., 
decidua ; end., endothelium of maternal capillary ; pi., plasmodium ; n.z., necrotic 
zone of decidua. 
The cytological characters of cyto- and plasmodi-trophoblast are here brought out. 
The section passes through an opening, eroded by the plasmodium, in the wall of a large 
sinus-like capillary. The endothelium is still partly preserved, and covers the upper 
portion of decidua. The vessel opens by a wide gap into the implantation cavity, and 
the opening is partially occupied by a large mass of irregular vacuolated plasmodium. 
This is continuous with the necrotic zone of the decidua, from which it is distinguished 
by a difference in colour. The plasmodium is not continuous with the other portion 
of decidua ; between them there is a narrow space containing a few leucocytes. Under 
the endothelium there are several large apparently degenerated decidual cells. The 
guiding line to the endothelium touches one of these cells. 
