86 FOLLICULAR DERIVATIVES IN VERTEBRATES 



yolk 



in 



nucleus 



^ 

 ^v-^ 



hormone 



,•• 



Fig. 66a. Granulosa cells. Apical cell-space containing phagocytosed ovular 

 substances; basal cell space filled with basal vacuole. 



(Fig. 65). Even the yolk-granules larger than the original 

 granulosa cells are phagocytised, so that the height of the 

 cells may increase sevenfold. Through resorption and phago- 

 cytosis the original contents of the ovum disappear and the 

 follicular wall is deformed under the pressure of the adjacent 

 parts of the ovary. 



We shall mark this point as the end of the a-stage, whose 

 characteristics are (i) enlargement of the granulosa cells; 

 (ii) conversion of the granulosa syncytium into single cells; 

 (iii) lively production of basophil granules; (iv) extrusion 

 of the liquefied granules, and (v) resorption and phago- 



