508 MR. r. E. BEDDAKD ON THE DEVELOPMENT AND [DeC. 7, 



Stage I. — The earliest stage of these bodies is represented in 

 fig. 1 ; its different constituents are figured, highly magnified, in 

 figs. 5, 14-20. 



The whole structure is situated near to the surface of the ovary, 

 with which indeed it is still in continuity ; the germinal epithelium 

 {ge), which is apparently not everywhere present as an external layer 

 in the adult ovary, is here conspicuous by its presence ; it forms a 

 mass of cells, the nuclei of which are so large and so closely pressed 

 together that I have found it impossible to detect any cell-outlines 

 (see fig. 1). These thickly clustered groups of epithelial cells seem to 

 correspond to the " epithehal islands " of many writers (see Iwakawa, 

 G.J. M.S. 1882, p. 266). The nuclei of these cells are deeply stained 

 by borax carmine, and for the most part rounded or oval in contour, 

 though frequently (perhaps owing to the hardening-reagent) some- 

 what angular. The staining-fluid is not evenly taken up by the 

 whole nucleus, but a peripheral layer, sometimes confined to one pole 

 of the nucleus, is very deeply stained, the central regions being compa- 

 ratively pale. 



The germinal epithelium is immediately continuous with a mass 

 of cells which form a hollow sphere, partly occupied by a plug of 

 cells of a somewhat different appearance ; the spherical mass of cells 

 is quite close to the surface and connected with the germinal 

 epithelium by a very short neck, which is as wide as the area occupied 

 by the patch of germinal epithelium. 



Tlie peripheral mass of cells is already differentiated into two 

 distinct layers, which are distinguishable from each other by the 

 characters of the component cells and more particularly of their 

 nuclei. 



The outermost layer is of course the one that is in contact with 

 the germinal epithelium ; the outlines of its cells are not very visible 

 in my preparations : between the nuclei of the cells is a fibrous 

 substance moderately stained by borax carmine ; this appears to 

 me to be the slightly altered protoplasm of the germinal cells 

 themselves, and not to be an inroad of connective-tissue stroma-cells. 

 The germinal cells bear, however, a very striking resemblance to 

 connective-tissue cells. 



Balfour has figured (Q. J. M. S. 1878, pi. xvii. fig. 10) and described 

 (p. 390) a condition of the Elasmobranch ovary which is so far very 

 similar to that which I have just described, and which gives me 

 greater confidence in stating that the cells displayed in fig. \,f.e, of 

 Plate LII. are really germinal and not stroma-cells. 



He says (p. 391) : — "The surface of the ovarian region ... is 

 covered by a distinct . . . pseudo-epithelium . . . The cells of the 

 pseudo-epithelium have one peculiarity very unlike that of ordinary 

 epithelial cells. Their inner extremities are prolonged into fibrous 

 processes which enter the subjacent tissue, and, bending nearly 

 parallel to the surface of the ovary, assist in forming the tunic 

 spoken of above. This peculiarity of the pseudo-epithelial cells 

 seems to indicate that they do not essentially differ from cells which 

 have the character of undoubted connective-tissue cells, and renders 



