514 MR. F. K. BEDDARD ON THE DEVELOPMENT AND [DeC. 7, 



one cell thick, but the nuclei of its constituent cells are so crowded 

 together that it is not easy to be certain upon this point. The 

 outlines of the follicular cells are in many places plainly visible, and 

 irregular processes (Plate LIII. fig. tt) project from these cells toward 

 the interior of the mass. This may very well be owing to the 

 shrinking of the central mass of cells', and the consequent breaking 

 away of its connection with the peripheral epithelium. A comparison 

 of the complete series of sections through the developing ovum (the 

 section fig. 6 is towards the middle of the series) shows that, 

 whether or not there is a connection between the entire periphery of 

 the central cells and the follicular epithelium, there certainly is such 

 a connection throughout a limited area lying on that side of the ovum 

 which is nearest the external surface of the ovary, a little above (or 

 below) the pedicle which unites the germinal epithelium with the 

 ovum. In this region the nuclei were more abundant and crowded 

 together than in the central cells of the mass, and were of uniform 

 size and rounded form ; in fact they show an exact similarity to the 

 nuclei of the follicular epithelium,* which in this stage, as already 

 mentioned, forms a distinct layer. The mass of cells which connects 

 the follicular layer with the central cells is therefore closely similar 

 to the follicular layer, and has the appearance of a proUferation and 

 growth inwards of that layer. The central cells, as in the previous 

 stage, have nuclei of varying size ; some are long and oval, and others 

 shorter and more spherical ; the latter resemble in every particular 

 the nuclei of the surrounding follicular layer. 



A characteristic feature of this stage is the commencing formation 

 of yolk, which is visible here and there (figs. 27-31) in the cells of the 

 central mass, and in the form of droplets of homogeneous appearance 

 and varying size. This formation of yolk is not confined to the 

 central cells, but is recognizable also in the cells which make up the 

 follicular layer. 



Here and there among the central cells are homogeneous masses, 

 evidently the same as those referred to in the description of Stage I. 

 as a probable resultant of the breaking-down and fusion of certain of 

 the central cells. These masses were, however, much less developed 

 than in the earlier stage. 



This stage is evidently, from the facts above narrated, in a further 

 condition of development than that which I have termed Stage I. ; 

 this is also shown in the gradually-advancing separation of the peri- 

 pheral layers from the germinal epithelium of the ovary. 



In the earlier stage the pedicle which unites the epithelial layers 

 with the germinal epithelium on the surface of the ovary is not only 

 very thick, but composed almost entirely of germinal epithehal cells 

 in a state of active multiplication. The stroma of the ovary had 

 barely penetrated into this mass of invaginated germinal cells. 



In Stage II. the body is just as near to the surface of the ovary, 

 and there is a shallow depression on the surface of the ovary corre- 

 sponding in position to the centre of the pedicle of attachment, which 

 would appear to be the remains of the invagination of the germinal 

 epithelium. The activity of the germinal epithelium has, however. 



