120 THE PHYSIOLOGY OF REPRODUCTION 



germinal epithelial nuclei. (6) Protobroque cells, Variety b. 

 The cells belonging to Variety a divide, and give rise to more 

 cells of the same kind, as well as to protobroque cells of the b 

 variety. In the latter the nuclei are less granular, and contain 



Early ovogenetic stage. 



Leptotenic stage. 



Fia. 24. Developing ova from ovary two days before birth. (After 

 Lane-Clay pon.) 



a certain number of fine chromatin filaments, (c) Deutobroque 

 cells. The protobroque cells of the b variety likewise divide, 

 and give rise to more protobroque cells, similar to themselves, 

 and also to deutoBroque cells. These latter are larger in size, 



Early. Synaptenic stage. Late. 



FIG. 25. Developing ova from ovary about one day before birth. 

 (After Lane-Claypon.) 



and contain nuclei with the chromatin arranged in the form of 

 a reticulum. 



II. Later changes : (a) Leptotenic stage. Certain of the 

 deutobroque nuclei become gradually differentiated, the 

 chromatin during the leptotenic stage passing through a process 

 in which it breaks up into fine filaments ; these are distributed 



