Chap, xxxii.] FEMALE GENITAL ORGANS. 259 



stroma. These follicles are spherical or slightly oval, 

 of about yo^oTJ i nc h i 11 Diameter, and each of them is limi- 

 ted by a delicate membrana propria. Inside of this is 

 a layer of flattened, transparent, epithelial cells, each 

 with an oval, flattened nucleus; this is the mem- 

 brana yranulosa. The space within the follicle is 

 occupied by, and filled up with, a spherical cell the 

 ovum cell, or ovum. This is composed of a granular- 

 looking protoplasm, and in this is a big spherical, or 

 slightly oval, nucleus the germinal vesicle. The 

 substance of this is either a fine reticulum, limited 

 by a delicate membrane, with one or more nucleoli 

 or germinal spots, or it is in one of the phases of 

 indirect division or karyokinesis, thus indicating 

 division of the ovum. 



346. (c) From this cortical layer to the zona 

 vasculosa we find embedded in the stroma isolated 

 Graafian follicles, of various sizes, increasing from the 

 former to the latter. The biggest 

 follicles measure in diameter about 

 J^- inch. Those of the middle layers 

 are of medium size (Fig. 142). In them 

 we find inside the membrana propria 

 the membrana granulosa, made up of a 

 single layer of transparent, columnar. 



Ii- v i n mi i ^.i Fie. 142. A Small 



epithelial cells. Ihe ovum, larger than Graafian fi.iiifU-, 



in the small cortical follicles, fills out S." tl 



the cavity of the follicle, and is ^^J^WS* 



limited by a thin hyaline cuticle the t^membmuaS^u- 



zona pellucida. This appears as an JSftbJSSrtS^ffi 



excretion of the cells of the membrana roSi vy a twn 



i mi i P ii zona i>ellucidH, aiid it 



granulosa. Ihe protoplasm ot the induSS a g mmai 



/i -n i 5 rrii vesicle or nucleus 



ovum is fibrillated. The part sur- with the intranuclear 



.. reticulum. (Atlas.) 



rounding the germinal vesicle is more 

 transparent, and stains differently in osmic acid than 

 the peripheral part. The big nucleus, or germinal 

 vesicle, is limited by a distinct membrane, and inside 



