THE FEMALE REPRODUCTIVE OKMJANS 



513 



body. The egg now contains only one-half the specific number of chromo- 

 somes; the full specific number is restored at fertilization by the addition 

 of the male reduced complement carried by the sperm. 



Development of the Ovarian Follicle. The development of the 

 ovarian follicle goes hand in hand with that of the ovum and can be 

 readily followed in ovaries from individuals of different ages, children 



K 



; V *1BK3 



*& 53E 

 FIG. 452. FROM A SECTION OF THE OVARIAN CORTEX OF A NEW-BORN KITTEN. 



K, Pfliiger's tubes; Ke, germinal epithelium; m, mitosis; Sir, ovarian stroma; 

 Ub, primitive follicles. Moderately magnified. (After Kolliker.) 



and adults, the ripe follicles and corpora lutea appearing only after 

 puberty. The process begins in the germinal epithelium in which certain 

 cells so increase in size that they may be readily distinguished as future 

 ova. As noted above, it is still an open question whether the primordial 

 germ cells are genetic derivatives of the germinal epithelium or specific 

 sex cells which have wandered into and become mingled with the cells of 

 the peritoneal epithelium. More frequently, however, the earliest step in 

 the process consists in the growth of solid cell columns from the layer 

 of germinal epithelium into the cortical stroma of the ovary. These 

 cell columns are known as Pfliiger's tubes, though, except occasionally 

 at the extreme surface of the organ, they lack a true tubular form and 

 possess no vestige of a lumen. Felix, however, concludes that Pfliiger's 

 cords do not occur in the human female. 



