OVARIES IN TELKOSTEAN AND ELASMOBRANCH FISHES. 195 



the same paper an aborted ogg is described as consisting of 

 a ^' gallertartigen Masse/' in which Avere seen degenerating 

 cells and " vielleicht anch weisse Blutkorperchen." No 

 mention is made by Stnhlmann of a growth or proliferation 

 of follicnlar epithelial cells in connection with the dissolntion 

 of ova. The appearances thns described by Stuhlmann — 

 and these are the only allnsions in this paper to egg 

 absorption — are those characteristic of the final stages in the 

 process of degeneration. 



Ruge (1887) in an elaborate memoir (1889) describes the 

 histological changes which accompany the degeneration of 

 intra-ovarian ova in two species of Amphibia, viz. Sala- 

 mandra macnlosa and Siredon pisciformis. Euge's 

 main results may be summarised as follows : — The death of 

 the egg is follo^ved by hypertrophy of the blood-vessels in 

 the follicular investments, and by a proliferation of the cells 

 thereof. In the second place, the degenerating egg is pene- 

 trated by elements derived from the follicular epithelium 

 and from the blood-vessels. These cells become charged 

 with yolk particles which are taken bodily into their proto- 

 plasm. The final products of degeneration are absorbed into 

 the surrounding blood-vessels. A gradual reduction in size 

 and ultimate disappearance of the egg are thereby effected. 



In " spent " ovaries of the plaice and sole Cunningham 

 (1898, pp. 117 — 122) found opaque granular masses which 

 proved on examination to be degenerate ova. These bodies 

 were at first thought to be diagnostic of the "spent" con- 

 dition, but they were subsequently found also in immature 

 ovaries. " Each consists of a mass of yolk globules of 

 various sizes contained in a follicle ; between the yolk 

 globules are nuclei and cells, the latter not distinctly defined. 

 The process which is taking place is evidently closely similar 

 to that which I have described as occurring in an empty 

 follicle. A proliferation of cells has taken place from the 

 walls of the follicle towards the interior, the cells penetrating 

 into the interior of the mass of yolk, and doubtless effecting 

 its absorption. The question arises whether these cells 



