196 WILLIAM WALLACE. 



are derived from the follicular epithelium or from 

 the connective tissue of the wall of the follicle, and I 

 consider the latter alternative is correct." 



The present observations on Zoarces leave no doubt as to 

 the important part played by the follicular epithelium in the 

 process of absorption of ova. There is, as Cunningham 

 has remarked, a proliferation of cells from the walls of the 

 follicle effecting the absorption of the egg, but it is certain 

 that the source whence these cells are derived is not, as 

 Cunningham supposed, the connective tissue of the follicular 

 wall, but the follicular epithelium. It is this layer, and 

 only this layer, which has to do with the absorption 

 of the egg. The process is essentially different from what 

 occurs in an empty follicle from which an egg has escaped. 

 There is no proliferation of the follicular epithelial cells in 

 ruptured follicles (fig. 27). 



For the purpose of the present research numerous sections 

 were cut of ovaries of a considerable number of immature 

 and adult females of Zoarces caught at diiferent times of 

 the year. The material employed was for the most part fixed 

 in Bles's fluid, and stained either with borax carmine or with 

 hcemalura and eosin. 



The follicular epithelium of small immature eggs such as 

 are represented in figs. 6 — 10 may assume either of two well- 

 marked forms : 



(1) The follicular epithelium may consist of a layer of flat 

 pavement epithelium, in which the deeply staining nuclei are 

 disposed with their long axes parallel to the surface of the 

 egg. The epithelium is bounded on the outside by a base- 

 ment membrane, the membrana propria folliculi, and 

 on the inside, next the egg, by a membrane with similar 

 optical and staining properties, viz. the zona radiata. 

 This is by far the more usual condition of the follicular 

 epithelium. In a minority of cases, however, the follicular 

 epithelium has a different aspect. 



(2) The follicular epithelium is a relatively deep layer of 

 columnar cells (fig. 16), whose inner ends are rounded and 



