REPRODUCTION. 



651 



ligerous disc (Fig. 318). The cavity of the follicle contains a slightly 

 yellowish, alkaline, albuminous fluid, a transudate in all probability 

 from the blood-vessels. The Graafian follicle is of especial interest, 

 for it is in this structure, and more especially in the proligerous 

 disc, that the true germ-cell or ovum is developed. 



The ovum is a spheric body measuring about 0.3 mm. in diameter. 

 It consists of a mass of living, protoplasmic material, cytoplasm, a 

 nucleus or germinal vesicle, and a nucleolus or germinal spot. The 

 cytoplasm presents toward its central portion a quantity of granular 

 material, partly fatty in character, the deutoplasm or vitellus. The 

 peripheral portion of the cytoplasm is surrounded by a delicate 

 radially striated border, the zona pellucida or radiata (Fig. 319). 



FIG. 317. UTERUS, FALLOPIAN TUBES AND OVARIES; POSTERIOR VIEW, i, i. 

 Ovaries. 2> 2. Fallopian tubes. 3,3. Fimbriated extremity of the left Fallopian 

 tube seen from its concavity. 4. Opening of the left tube. 5. Fimbriated 

 extremity of the right tube, posterior view. 6, 6. Fimbrias which attach the 

 extremity of each tube to the ovary. 7, 7. Ligaments of the ovary. 8, 8, 9, 9. 

 Broad ligament. 10. Uterus, n. Cervix uteri. 12. Os externum. 13, 13. 

 Vagina. 



The nucleus consists of a nuclear membrane enclosing contents. 

 The latter consist of an amorphous material in which is embedded 

 a network, some of the threads of which have a strong affinity for 

 certain staining materials, and hence are known as chromatin, while 

 others stain less deeply and are known as achromatin. 



The Fallopian Tubes. The Fallopian tubes are about 12 centi- 

 meters in length and extend from the upper angles of the uterus 

 to the ovaries. Each tube is somewhat trumpet-shaped, the narrow 

 portion being close to the uterus, the wide portion close to the ovary. 

 The outer extremity of the tube is expanded and subdivided, and 

 presents a series of processes termed fimbriae, one of which is attached 



