CHANGES IN THE OVARY 115 



germ-cells or oogonia give rise, after a series of two or more divisions, 

 to ova, follicle-cells, and interstitial cells. The two latter types of 



FIG. 28. Various stages in the development of the Graafian follicle of the 

 rabbit. (From Schafer.) 



A, From young rabbit, showing Pfltiger's egg-tubes ; B, C, D, E, successive 



later stages. 



cell may remain for a time as reserve cells or may be absorbed as 

 pabulum for the developing cocyte. 



The changes involved in the production of ova have been fully 

 investigated by von Winiwarter l in the rabbit. These changes 



1 Von Winiwarter, "Eecherches sur 1'Ovogenese de 1'Organogenese de 

 1'Ovaire des Mammiferes," Arch, de Biol., vol. xvii., 1900. 



