THE FOLLICLE SACS OF THE AMPHIBIAN OVARY. 



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the mature ovarian egg is in contact with the outer membrane of 

 the wall of the ovary, I have never found the opening of an empty 

 follicle sac to be more than 0.38 mm., the average being 0.20 

 mm. This shows that the edges of the opening tend to close 

 in as soon as the egg has passed out of the ovary. 



On examining a longitudinal section of an empty follicle sac 

 (Fig. 3), one finds that the two layers of which its walls are 

 composed are united at frequent intervals, and that, on the wall 

 and in the spaces between the layers, there are numerous cells. 



FIG. 5. A portion of the wall of a follicle sac after degenerative changes have 

 begun. Zeiss. apoc. 2 mm. Oc. 8. 



Sections of the small blood vessels which supplied the eggs with 

 nourishment are also found occasionally (Fig. 3, C). The cavity 

 of the follicle sac is lined with cells, several layers deep in places, 

 particularly at the closed end of the sac. These cells are doubt- 

 less the ones that lay between the zona pellucida and the outer 

 covering of the egg at an earlier period, and their confinement in 

 a much smaller space must explain why they appear so numer- 

 ous, as I have never found any evidence of cell division at this 

 time. 



A part of the wall of a follicle sac more highly magnified is 

 shown in Fig. 4. The cells lining the cavity of the sac are seen 



