PLATE XIII. 



Fig. 10.— Young follicular o5cyte in which the vitelline body, o, is developing. 

 Here is seen in this stage scarcely more than the central vesicle, the whole 

 clouded by a zone of darkly staining granules. The body is distinctly a part 

 of this zone, b is the germinal vesicle and c the stem of epithelial cells 

 which attaches the egg to the ovary. 



Fig. 11.— An oocyte somewhat older than at figure 10, in which the vitelline body 

 ie assuming a concentrically striated wall. The clear central part of the body 

 is the central vesicle, though it possesses no well-defined wall, as in figure 10. 

 Near the periphery is a vacuole, a. 



Fig. 12.— The vitelline-body has moved out from the nuclear wall. It not only 

 lies in the vitelline-zone, but is closely surrounded by a dense layer of gran- 

 ules. This is probably food material which it ie extracting from the zone and 

 is storing up. Between the periphery of the vitelline body and the central 

 mass is a coarse network, which I take to be no more than the cytoplasmic 

 reticulum made prominent by the deutoplasmic granules which adhere to it. 



Fig. 13.— The vitelline body is now separated from the germinal vesicle by al- 

 most the diameter of the cell. It here possesses a clearly defined outer edge, 

 which separates it sharply from the surrounding structures. 



Fig. 14.— Instead of a body formed of concentric layers, there is a collection of 

 large globules which stain very black in iron-htematoxylin. Those at the 

 center are in the shape of rods, and resemble chromosomes. 



Fig. 15.— a follicular egg, showing the egg-stalk, a, attaching the large oocyte 

 to the ovarian wall. The vitelline body possesses a wall spirally wound about 

 the central vesicle. 



Fig. 16. — The germinal vesicles of eggs at this stage of development possess 

 very large nucleoli, which are usually vacuolated. The smaller bodies stain 

 darker, and have much the appearance of being cast from the nucleolus. 



Fig. 17. — A highly magnified vitelline body, showing its well-defined outer edge 

 and the network of fibers within. 



Fig. 18. — A follicular o5cyte, showing the peritoneal coat, a. Here are found 

 again some new characteristics in the vitelline body. The central vesicle is 

 comparatively large and distinct, and instead of being clear is filled with 

 darkly staining rods, or pseudo-chromosomes. 



Fig. 19. — There is shown here a condition which is very rare. The cytoplasm 

 surrounding the vitelline body is faintly radially striated. 



