1880.] 



in the common Fowl and in the Rabbit. 



241 



Nor can I say whether the clear interval between the follicnlar 

 epithelium and the zona radiatd in fig. 11, and which seems to 

 be bridged across here and there by processes of the follicular 

 epithelium cells, is the section of a homogeneous " chorion," or merely 

 a layer of clear coagulated fluid ( 8 ) . 



Epithelium of the Graafian Follicle. — The follicular epithelium of the 

 smallest follicles is a single layer of oblong or cubical cells (figs. 5, 6, 

 8, 9,f. e). As the follicle grows the cells become more columnar. In 

 larger follicles (figs. 10 and 11) the epithelium is two or more cells 

 deep ( 9 ). The cells are not arranged in layers, but irregularly disposed. 

 They are for the most part rounded or angular in form, but between 

 these smaller cells other longer ones are met with, which extend 

 through the thickness of the epithelium, and are pyriform in shape, 

 generally with the stalk of the pear directed outwards (fig. 10, p). 

 These seem to be the cells which Waldeyer figures as being continuous 

 with the zona radiata, but, as will be seen from what has been stated 

 above, I have not been able to confirm their continuity ; indeed, the 

 larger end of the cell does not always reach the inner border of the 

 follicular epithelium. On the other hand, the stalk of the pear always 

 extends at least to the outer border of the epithelium, and may even 

 in some cases be traced into the connective tissue coat of the follicle. 

 These cells call to mind the pyriform cells which cover the surface of 

 the developing Elasmo branch ovary, and which also are traceable at 

 their attached smaller ends into the stroma of the organ ( 10 ). 



Ovarian Ovum of the Babbit 



The following description is derived from the study of sections of 

 the ovaries of rabbits, which were either full grown or nearly so. The 

 ovaries were removed while still warm and placed in a concentrated 

 solution of picric acid. After hardening in this, they were transferred 

 to alcohol, which was frequently changed. Sections were then pre- 

 pared and stained either with magenta dissolved in oil of cloves, and 

 subsequently mounted in Canada balsam, or they were stained with 

 Beale's carmine and mounted in glycerine, or sometimes in balsam. In 

 sections of such ovaries, as is well known, permanent ova and Graafian 

 follicles are to be found in every stage of growth. 



Germinal Spot. — In small ova the germinal spot, as in the bird, is 

 generally represented by a collection of darkly staining granules, im- 

 bedded in a homogeneous, or very finely granular matrix (figs. 14 — 20). 

 The outline of the macula is generally less well defined than in 

 corresponding ova of the bird, and the shape is more irregular. 

 This granular condition of the macula is not confined to the small ova, 

 for it occurs also in those which are surrounded by a double layer of 

 follicular epithelium (fig. 20), and even in some which are contained 

 in large Graafian follicles in which there is already a considerable 



