136 



in all directions from the pit in which the embryo lies, and, 

 arching over to the mesometrium, carry away the blood from the 

 trophoblastic lacunae to empty it into the uterine veins. There 

 still remains to be mentioned a peeuliar layer four or five cells 

 deep of flattened vacuolated cells (Figs. 13, 1 — 4) placed round 

 the lumen of the embryonic pit and also found, though less 

 strongly marked, round the ordinary lumen of the uterus. By the 

 degeneration of the epithelium it is of course brought into imme- 

 diate proximity with the trophoblast. The vacuoles are elongated, 

 corresponding to the shape of the cell, and irregular; they cer- 

 tainly contain fat, (Fig. 13) but I think it is possible that they 

 may contain some other substance as well. 



In the very few osmic preparations I possess of this stage many 

 of the vacuoles appear empty; this may of course be due either 

 to the fact that the fat has been used up or that some other 

 substance, very possibly glycogen, which was originally present, 

 has been used up or dissolved out. Unfortunately I have not yet 

 been able to determine this point. The exact stage is very transitory 

 and not easy to obtain; the cells soon become completely crushed 

 and flattened, the vacuoles disappear (Figs. 1 — 4, 28) and the 

 nuclei degenerate. The layer of flattened cells so formed is found 

 not only here but also at the sides of the allantoidean region 

 of the trophoblast, and wherever preseot it serves very conve- 

 niently as a means of distinguishing between trophoblastic cells 

 on the one hand, and on the other the remainder of the sub- 

 epithelial tissues; and even when, in the omphaloidean region 

 which we now are concerned with, it becomes pierced and broken 

 by the emigration of amoeboid megalokaryocytes, small patches 

 nevertheless remain which may be identified as the relies of the 

 vacuolated flattened cells. 



The capsularis is at the maximum of its development on about 

 the eight day; from this time onwards it steadily decreases in 

 thickness and ultimately disappears. The changes which take place 

 during this degeneration are simple. Firstly the subepithelial tissue 

 becomes broken up, the cells separating widely from one another; 



