494 A. A. W. HUBBECHT. 



to receive the processes of the trophoblast in the cavities of its 

 crypts. Between the epithelial proliferation here more fully 

 described maternal blood-vessels, supported by connective 

 tissue, have from the first taken their course. In figs. 24 

 and 25, but more especially in fig. 74, the relation of this 

 connective and vascular stroma to the epithelial tissue of the 

 crypts can be clearly seen. There can be no doubt but that the 

 proliferated epithelial tissue is more massive than the san- 

 guiniferous strands penetrating between these epithelial crypts. 



In comparison to the thickness of the wall of the uterus the 

 epithelial proliferation in figs. 24 and 25 is also seen to have 

 considerably increased in significance, and if we now compare 

 the outline figs. 3 and 4 with figs. 5 — 7, all of them corre- 

 sponding to the stages hitherto considered, we see that matters 

 have assumed a very diflFerent aspect, and that the lateral 

 cushion-shaped parts where the first omphaloidean attachment 

 of the blastocyst is brought about are no longer much thicker 

 than the antimesometrical concavity, but rather the contrary. 



The epithelial proliferation, which at first took place at a 

 slower rate in this placentary region, has very rapidly overtaken 

 in its growth the lateral portions. The uterine glands, although 

 they are considerably flattened when the proliferation and 

 crypts have grown to the size of figs. 6 and 7, are always in the 

 possession of their duct, which takes its course towards the 

 surface parallel to the long axis of the crypts. In the lateral re- 

 gions of epithelial proliferation against which the blastocyst has 

 become attached there is no semblance, as we have already ob- 

 served (cf. fig. 7), of the formation of crypts ; here too, however, 

 delicate vascular tracts can be noticed between the proliferated 

 epithelial cells (fig. 20), these vascular spaces remaining in com- 

 munication with the vessels of the deeper connective tissue. 

 We have now obtained detailed information concerning various 

 changes which the maternal tissues undergo previous to and 

 simultaneously with the definite fixation of the blastocyst 

 against these tissues. When this fixation has come about a 

 new phase is entered upon, which is characterised by important 

 modifications. And whereas up to here we have noticed a 



