IIO H. H. NEWMAN. 



Stage 5 (Fig. 5). Later stages show as a rule a more or less 

 complete loss of the elongated condition. The figure is a good 

 example of a somewhat more advanced condition, the diameter 

 of such follicles averaging about .22 mm. 



Stage 6 (Fig. 6). Here we have about the maximum develop- 

 ment of the solid follicle, before a disintegration of follicular cells 

 begins to give rise to a lumen. The compound epithelium is 

 from five to seven layers thick and the capsule of stroma cells is 

 more sharply defined than ever. Such follicles have an average 

 diameter of about .3 mm. 



Stage 7 (Fig. 7). At this time through the cytolysis of some 

 of the components of the epithelium various fluid-filled cavities 

 appear midway between the ovocyte and the periphery of the 

 follicle. Average diameter, about .35 mm. 



Stage 8 (Fig. 8}. At this stage lumen formation has made 

 considerable progress and the follicle cells may be considered 

 as forming two zones: a zone around the ovocyte, which is 

 destined to form the discus proligerus and a zone occupying a 

 peripheral position. The intervening cavity is filled with fol- 

 licular fluid and cell fragments. Average diameter of such 

 follicles, about .5 mm. 



Stage 9 (Fig. 9). At this time there is evinced a strong tend- 

 ency for the ovocyte, with its zone of follicular cells, to occupy an 

 excentric position due to the breaking away of the connecting 

 strands of follicle cells on one side and the thickening by con- 

 traction of the others. This is evidently a step in the establish- 

 ment of the definitive discus proligerus. Average diameter, .6 mm. 



Stage 10 (Fig. 10). Here we have another step in the develop- 

 ment of the discus proligerus. Many of the largest follicles 

 found have been in this stage of development. Average diameter, 

 about I mm. 



Stage IT (Fig. u). This is what might be termed the definitive 

 follicle. The discus proligerus is in the form of a smooth mound 

 of follicle cells projecting into the lumen from one side of the 

 follicular wall. The remaining part of the follicle is lined with 

 a thin smooth sheath of follicle cells. There is a great deal of 

 variation in the size and shape of the definitive follicle, many 

 being flattened or otherwise distorted by the presence of various 



