80 DR. J. W. JENKIXSOX 0^^ THE [Feb. 6, 



(/3) In addition to these typical cells I have found in the Cow 

 elements which look remarkably like goblet-cells. They are to be 

 seen (PI. III. fig. 8, gl.) wedged in between the ordinary cubical 

 cells which cover the villi. Each cell contains a goblet-cavity 

 filled with a granular coagulum ; the nucleus is small and pressed 

 against the side of the goblet. I have not succeeded in getting the 

 granules to stain with muci-carmine or much^matein. 



(v) The large oval binucleate cells (PI. III. fig. 8, bi.), foimd in 

 both the extra-cotyledonary trophoblast and upon the villi, have 

 been described by both Bonnet and Kolster, Each cell has a very 

 definite superficial membrane, a dense finely granular cytoplasm, 

 and two large oval nuclei provided with a rich reticulum of coarse 

 chromatin granules and two or more plasmosomes. The nuclei 

 may divide mitotically. 



According to Kolster, these cells are maternal leucocytes which 

 have migrated through the uterine epithelium, grown at the 

 expense of the cell-debris accumulated in the lumen uteri, doubled 

 their nuclei by amitotic division, and become incorporated in the 

 trophoblast. It is true that these or closely similar cells are 

 occasionally found free between the foetal and maternal tissues ; 

 but apart from that I do not believe there is the least evidence 

 for the view put forward by Kolster. That leucocytes migrate in 

 large numbers during gestation through the maternal epithelium 

 and are found in the " uterine milk " is certainly an indisputable 

 fact ; these cells are, however, far larger than any leucocytes that 

 I have ever found, and quite dissimilar to any that I am acquainted 

 with. Moreover, Kolster does not figure a good series of the 

 alleged intermediate stages between the unmodified white corpuscles 

 and these very peculiar cells. The question must remain an open 

 one until the mode of first appearance of these elements in the 

 unattached blastocyst has been ascertained *. 



3. The '•'■ Diveriioida Allantoidis." 



The ends of the chorionic sac — placed in the cornua uteri — are 

 produced into long, tapering filaments, supposed by the earlier 

 embryologists to be diverticula of the allantois pushed through 

 perforations in the chorion. Bonnet has shown (for the Sheep) 



* Asslieton has now shown that these cells are of foetal origin. See postscript to 

 this paper. 



Explanation of Text-fig. 29 (opposite). 



Sheep. — Formation of new crypt-cavities by the downgrowth of cell-masses from 

 patches of unmodified — not flattened — epithelium. 



In fig. a the solid downgrowth is shown in continuity with the cryjjt epithelium ; 

 in fig. h it is cut across ; in fig. e it has a lumen communicating with the cryyjt- 

 cavity above ; in fig. d the lumen though well-developed is not yet open : and 

 in fig. c the lumen is as yet exceedingly small. 



All the figures taken from the basal crypts of a cotyledon of a tVetus measuring 

 14 cm. (3rd month according to Kolster.) 



