THE FEMALE ORGANS OF GENERATION. 



249 



lum of fine fibrils. Within the vitellus is seen the nucleus or 

 germinal vesicle (also presenting a delicate reticulum of fibrils), 

 situated eccentrically, spherical in shape, measures 0.037 to 

 0.451 mm. in diameter, shining, transparent, and contains the 

 nucleolus or germinal spot, which is a highly refractile body, 

 finely granular, supposed to be non- vesicular, and measures 

 0.0046 to 0.0068 mm. in diameter. 



The mature Graafian follicle, which is seen on the surface 



Fio. 108. A, primordial egg of the human being: 8 month*' fostus. B, primordial follicle of the 

 rabbit. C, primordial follicle of a dove. D, a somewhat older follicle of the same animal ; commence- 

 ment of the formation of the subordinate yolk. E. blind end of the ovary of an nscaris nigrovenosa ; 

 germinal vesicles (some of which possess a germinal spot and Schriin's "granule") in a diffuse mass of 

 protoplasm. F, egg of the ascaris nigrovenosa from about the middle of the ovary ; Schron's grannie ; 

 commencement of the deposition of yolk-matter. (?, egg from a follicle (2 mm. in diam.) of the rabbit : 

 a. egg-epithelium ; 6, striated zone with radiating striae ; c, germinal vesicle ; d, germinal spot ; , yolk. 

 Waldeycr. 



of the ovary, giving rise to a prominence, ruptures during the 

 menstrual period and empties its contents, viz. : the ovum, 

 fluid contents, and discus proligerus into the Fallopian tube. 

 The cause of the rupture is an increase in the contents of the 

 follicle, and a fatty metamorphosis of the cells of the wall of 

 the follicle. As a result of this rupture of the Graafian vesi- 

 cle, there is formed a yellow body, the corpus lideum, which 



