284 GEORGE W. BARTELMEZ 



to form the stigma, which, as will be seen, plays an important 

 part in the orientation of the ovum in the oviduct. Figure 11, 

 taken from a median longitudinal section of an oocyte 83ju in 

 long axis, shows the close approximation of the follicle and epi- 

 thelial cells; in the whole stigmal area of this oocyte only a few 

 isloated stroma cells were to be found between the two epithelia. 

 The study of many ovaries shows that the stigma is formed accur- 

 ately in the long axis of the oocyte; the Y-shaped and branched 

 stigmas found in many of the follicles of certain ovaries have 

 their main axis in the long axis of the oocyte and actual devia- 

 tions from this condition are rare. 



In the majority of cases the oocytes come into contact with the 

 germinal epithelium during the second growth period, (0.15 to 

 0.4 mm.) and the stigma is formed at the free pole. The latter 

 frequently coincides with the vegetative pole of the oocyte, as 

 in all of the figures, but, as has been said, this is not essential for 

 normal development; the polar axis may lie anywhere in a plane 

 perpendicular to the long axis and so be variously related to the 

 surface of the ovary. Nevertheless the condition indicated in 

 diagram 2 is the. typical one, for it is the one found normally in 

 mature oocytes whatever may have been the condition in the 

 earlier stages. The factors which bring about the 'typical' con- 

 ditions in all oocytes that mature will be discussed in the follow- 

 ing section (p. 288). 



2. The blood supply of the follicle. The development of a 

 distinct blood supply, i.e., the differentiation of a theca vascu- 

 losa usually begins soon after the formation of the stigma. The 

 capillaries in the cortex of the ovary course about irregularly 

 between the primordial follicles, as may be seen in figure 2. As 

 the oocyte grows, it projects farther and farther from the surface 

 and owing to the outgrowth and anastomosis of fine branches 

 from the pre-existing vessels, the network becomes finer over the 

 bulging surface (figs. 3 and 4). At the same time there is a 

 proliferation of stroma tissue over the whole surface, except in the 

 region of the stigma, where such growth is inhibited as appears in 

 figure 15, which shows a cross section of a stigma (si.) Two layers 

 can now be distinguished in the connective tissue follicle: a very 



