650 



MANUAL OF PHYSIOLOGY. 



rest increase in number to form the small cells of the granular 

 tunic. As the follicle develops, it works its way toward the centre 

 of the ovary, and then approaches the periphery of the organ as 

 a fully-developed Graafian follicle. 



FIG. 247. 



CAD I AT 



Section of the ovary of a cat, showing the origin and the development of Graafian folli- 

 cles. (Cadiat.) a. Germ epithelium. 6. Graafian follicle partly developed, c. Earliest 

 form of Graafian follicle, d. Well-developed Graafian follicle, e. Ovum. /. Vitelline 

 membrane, g. Veins, h, i. Small vessels cut across. 



Microscopically, it is seen to be surrounded externally by a 

 capsule the tunica fibrosa, which is ill-defined from the stroma 

 of the ovary in which it lies. Beneath this is a layer of capil- 



