( 875 ) 



membrane reads in the manner, well-known in other mammals 

 (Tarsius, hedgehog, rabbit, bat,, etc.) by perceptible changes in 

 the uterine glands in the vicinity of this place of attachment and by 

 the formation of so-called trophospongia-tissue, consisting of a modi- 

 fication of the interglandular connective tissue, to which are added 

 proliferations of uterine and glandular epithelium. 



As the final product of these preliminary phenomena we now see 

 thai a pari of the maternal mucosa where the germinal vesicle 

 has coalesced with the mucosa, presents a more compact proli- 

 feration, while nearer the periphery the uterine glands, by strong 

 dilatation of their lumen, differ clearly from the other uterine 

 glands, as this is also the case in Tarsius, Lepns and other mam- 

 mals during early pregnancy. The dilated glands may be followed 

 up to their mouth; this mouth, however, no longer connects the 

 glandular lumen with the uterine lumen, since in this place the 

 embryonic trophoblast has disturbed the connection and covers the 

 mouths of the glands. 



This trophoblast now also shows unmistakable signs of cell-prolifer- 

 ation, although it does not at once attack and destroy the maternal 

 epithelium, as in the hedgehog, Tarsius, Tnpaja, etc. but rather finds 

 itself facing this maternal epithelium in ('nil proliferation, in the 

 manner stated by me also for Sorex l ). Instead of being closely 

 adjacent, however, spaces are left open from the beginning between 

 trophoblast and trophospongia, which spaces are partly mutually 

 connected and partly are subdivided into smaller compartments by 

 trophoblastic villi, attaching themselves to the trophospongia-tissue. 



In this manner the free surface of the trophoblast, facing the 

 embryo, obtains a knobbed appearance. 2 ) 



Already in early developmental stages, when there is as yet no 

 question of the folding off of the embryo and long before blood- 

 carrying allantoic villi have become interlocked with these tropho- 

 blastic villi for the further completion of the placentas we find in 

 the spaces between trophoblast and trophospongia numerous blood- 

 corpuscles of which we can not say that they have been carried 

 thither by maternal vessels exclusively, although there can be no 

 doubt that a connection between these spaces and the maternal 

 vascular system is established at an early date. In the manner, 

 indicated above, these spaces communicate also with the uterine 

 glands which are here dilated. And in these glands as well as in 



l ) Quarterly Journal of' Microscopical Science, vol. 8."). 



-' Certain modifications which I < bserved when the germinal vesicle develops 



in a uterus which is still in the puerperal stage, may be left out of account here. 



