39O PRACTICAL HISTOLOGY. [XXXVI. 



Between the tunica and membrana granulosa is a space which 

 encloses a fluid in the large follicles the liquor folliculi. 



(<?.) The ovum, composed externally of a hyaline membrane 

 the zona pellucida enclosing more or less granular cell-contents ; 

 the vitellus or yelk ; and placed excentrically in this the germi- 

 nal vesicle (corresponding to a nucleus), \vith its small excentric 

 germinal spot (corresponding to a nucleolus). 



(h.) Small Unripe Ova. Besides the difference in size, the 

 follicles show no separation between the tunica and membrana 

 granulosa. They form a layer of cells in which the small ovum 

 appears to be embedded. 



2. The Ovum (fig. 361). A fresh ovum may be obtained thus. 

 Take the ovary of a cow or sheep, which on its surface shows clear 



Cells of discus proligerus. 



Yelk. 



FIG. 361. Ripe Ovum of Ilabbit highly magnified. 



elevations about the size of peas, filled with a watery-looking fluid ; 

 these are ripe follicles. Prick the follicle and receive its contents 

 upon a slide. The liquor folliculi escapes, and with it the ovum 

 surrounded by the cells of the tunica granulosa. With (L) search 

 for the ovum in the fluid on the slide. Do not cover the prepara- 

 tion while doing so. If a cover-glass be applied, two strips of paper 

 must be placed under the cover-glass to avoid pressure upon the 

 delicate ovum. Observe the ovum, and in it will be seen the parts 

 already described and shown in fig. 361. 



3. T.S. Fallopian Tube (L and H). This is hardened in 

 Miiller's fluid or Flemmiug's fluid. Treat it in the same way as 



