268 T. IWAKAWA. 



examinations and graduating exercises. But we have both 

 arrived at the same conclusion, viz. that the omini does have 

 an epithelial origin. In regard to the mode of origin, we 

 have arrived at conchisions differing somewhat from any 

 that have yet been published. As before stated, the germinal 

 epithelium forms a complete investment of the ovary, in the 

 foem of flat polyhedral cells in a single layer. In surface 

 views (fig. 17) these cells are seen to differ considerably in 

 size in different areas, being generally smaller in those places 

 where newly formed ova are found, or where such are in 

 process of formation. The difference in size, however, is 

 not so great as surface views might lead one to think. In 

 sections passing through such areas (figs. 13 and 14) the 

 cells appear more crowded than elsewhere, and have greater 

 depth. In the least crowded areas the nuclei have a 

 flattened elliptical form, when seen in section, and are placed 

 at considerable distances apart. 



In the more crowded areas the nuclei are brought so close 

 together that the cell protoplasm is not always to be recog- 

 nised between them, and they are tilted up on one end, so 

 to speak, and often overlap one another (fig. 14). 



It is in these crowded areas that we meet with the germ- 

 cells,^ which lie at first in the germinal epithelium (fig. 15), 

 and are plainly a part of it. Such a section as that given 

 in fig. 15 would perhaps, at first sight, be supposed to 

 favour the view that the germinal epithelium is composed 

 of two distinct kinds of cells. There are some points in 

 this section, however, that will be more easily explained 

 after a description of surface views. 



I have found very often during the winter the nuclei of 

 the germinal epithelium in process of division, as seen in 

 fig. 2. Other cells of the same layer are found with two 

 distinct nuclei (figs. 11 and 12). The two nuclei may be 

 alike in general appearance (fig. 11), or one may present an 

 aspect quite unlike that of the original nucleus. The latter 

 case has been reproduced in fig. 12, in which four epithelial 

 cells are represented. In one cell there is seen, besides the 

 proper nucleus, which is precisely like the nuclei of the 

 neighbouring cells, a second somewhat larger body, which is 

 quite distinctly outlined, and which has a nucleus-like body 

 within. That this body lies wholly within the epithelial 

 cell there can be no doubt. This body represents a germ- 

 cell which has formed within the parent epithelial cell. 



The question at once arises, How does this endogenously 



^ As I am uucertain whether these cells give rise to both the primordial 

 ova and e,rauulcsa, I call them germ-cells. 



