142 T. THOMSON FLYNN 



which latter is sh(j\vii in the drawing. Only the nuclei of the 

 nest outside the range of attack are seen to preserve their 

 original shape and structure, the others being in the state of 

 degeneration. Apparently this consists in the loss of contour 

 through the breakmg down of the nuclear membrane followed 

 by loss of chromatin and virtual disappearance. Figs. 5 and 6 

 show stages in the proliferation of the chorionic ectoderm 

 cells. In all cases they give the impression of thrusting forward 

 wedge-shaped plugs which penetrate into the aggregations of 

 maternal nuclei. 



There happens to be but one gland present in the small 

 area to which the trophoblast is attached at this stage. This 

 is shown in fig. 7, which depicts a section through the actual 

 opening of the gland. Its uterine mouth is seen to be blocked 

 by the overlying chorion, the ectodermal portion of which may 

 now be regarded as forming two distinct portions, a basal 

 portion, the cytoblast (cyt.), and a plasmodial portion, the 

 plasmodiblast. The growth of the Plasmodium has extended 

 •a considerable distance, particularly on one side, where the 

 protoplasmic processes have caused degeneration in the gland 

 epithelium cells similar to that which occurs in the maternal 

 imclei. Here, as before, the nuclei have lost their contour, 

 their position in the cell-line, and their chromatin. They 

 decrease in size and disappear, being evidently ingested. 

 Further degeneration of the gland-cells is foreshadowed by 

 the presence of protoplasmic processes involving them. Also 

 in this figure will be seen remnants of syncytial nuclei and other 

 remains, haematids and leucocytes. 



That the cells of the plasmodiblast are phagocytic cannot be 

 doubted. Their eliect on the syncytial and gland nuclei is 

 some evidence of- this, but the presence of numerous rounded 

 granules such as those shown to the left of fig. 7 (ing.) and other 

 cellular debris makes the matter certain. 



Pigmented cells are present in the trophoblast. This pig- 

 ment is black and is arranged either as minute granules or as 

 an aggregation of streaky lines, usually in the neighbourhood 

 of the nucleus. 



