THE OVA AND OVARY IN MAN AND OTHER MAMMALIA. 219 



The stroma of the young ovary consists for the most part 

 of fusiform connective tissue corpuscles, and blood-vessels. 

 The walls of the young blood-vessels in the young stroma 

 consist of connective tissue corpuscles. The connective 

 tissue corpuscles are direct offshoots from the ovarian stroma, 

 and are found in contact with the yelk or protoplasm of each 

 primordial ovum situated among the germ epithelial cor- 

 puscles on the surface of the ovary. Wherever we find 

 primordial ova we see connective tissue corpuscles in contact 

 with the yelk of each. In all parts of the ovary we find the 

 nuclei of connective tissue corpuscles dividing. Sometimes 

 these corpuscles are swollen out into round bodies containing 

 three to four nuclei. In each egg cluster several of the in- 

 cluded germ epithelial corpuscles are in a much farther 

 advanced stage of development than their fellows. From 

 the walls of the meshes inclosing the egg clusters, delicate 

 processes of vascular connective tissue grow in, between, and 

 around individual corpuscles in the egg clusters, and by a 

 continued intergrowth of the young stroma in this manner 

 each individual of the group becomes at last enclosed in a 

 separate mesh or capsule. These last formed meshes are 

 the Graafian follicles. 



As a rule, each Graafian follicle is occupied by one young 

 ovum. The protoplasm or yelk of each ovum is in close 

 contact with the wall of each Graafian follicle. In contact 

 Avith the yelk of each young ovum, and indenting it, are 

 connective tissue corpuscles, which form part of the wall of 

 each Graafian follicle. In the formation of the membrana 

 granulosa, these connective tissue corpuscles in the wall of 

 the Graafian follicle, and in contact with the yelk of the 

 contained ovum, increase in number by division, their nuclei 

 swell out into little vesicles, and at last a perfect capsule of 

 such corpuscles is produced round the ovum. This capsule 

 is the membrana granulosa or follicular epithelium of the 

 follicle. At first the membrana granulosa consists of a simple 

 layer of corpuscles lining the follicle.^ The individual cor- 

 puscles of the membrana granulosa in the human ovary 

 measures about -j-oVotli inch. As the ovum becomes mature, 

 the corpuscles of the membrana granulosa proliferate, and 

 then many layers of small corpuscles are produced between 

 the ovum and the follicular wall. The cells of the mem- 



' The formation of the granulosa from a single layer of connective tissue 

 cells which are in origin independent of the germ-epithelium is paralleled 

 by the mode of development of the inner cellular membrane of the egg- 

 capsule in Cephalopods, as described by Ray Lankester, ' Phil. Trans.,' 

 1875, " Contributions to the Developmental History of the MoUusca." 



