248 MANUAL OF HISTOLOGY. 



ovary. A capillary reticulum surrounds the follicles, and is 

 situated in their internal membrane. 



The stroma of the hilum contains numerous lymphatics, 

 which have an arrangement similar to that of the veins. Sur- 

 rounding the follicles in their external lamina is found a dense 

 network of lymphatics. 



The nerves enter the ovary at the hilum with the arteries, 

 and they have been followed into the stroma between the large 

 follicles, but their ultimate terminations have not as yet been 

 ascertained. 



The follicles of the ovary, or Graafian follicles, consist of a 

 connective-tissue wall separable into two layers : an internal, 

 which contains the small capillaries, and an external, contain- 

 ing the large blood-vessels and lymphatics. The outer layer is 

 made up of the same connective tissue as the stroma of the 

 ovary, in which are numerous spindle-shaped cells. The inter- 

 nal layer consists of connective tissue, in which are numerous 

 and variously shaped cells, fusiform, stellate, and small round 

 bodies, the latter possessing amo3boid movement ; there are 

 also seen larger round or polygonal-shaped cells. This layer of 

 corpuscles is the metnbrana granulosa. Within the follicle, 

 and distending it, is an albuminous fluid holding a few bodies 

 in suspension. Situated in the follicle, usually at that part 

 most distant from the surface of the ovary although this is 

 not a rule without exception, since it is also found immediately 

 below the most superficial part of the follicle the ovum is 

 found surrounded by a collection of cells of the granular mem- 

 brane, known as the discus proligerus. Two kinds of cells 

 form the discus proligerus, the follicular and egg epithelium ; 

 the latter lie in immediate contact with the vitelline membrane, 

 and are closely adherent to it. 



An examination of the mature ovum demonstrates it to 

 measure 0.28 to 0.1379 mm. in diameter; it is spherical in 

 shape, and is a typical cell, consisting of an investing mem- 

 brane, the vitelline membrane, or zona pellucida, which is 

 a dense> transparent, homogeneous substance, apparently 

 pierced by numerous minute pores. This membrane is prob- 

 ably developed from the cells of the discus proligerus, and from 

 the layer described as the egg epithelium. The cell-contents, 

 protoplasm, or vitellus is a granular mass composed of albu- 

 minous and fatty particles, and a more or less distinct reticu- 



