OVARIES IN TELEOSTEAN AND ELASMOBEANCH FISHES. 201 



attacked, the thick fibrillar layer breaking up along the 

 fibres, and at length dissolving completely, before the third 

 or innermost showed any signs of disintegration. 



Fig. 23 represents what is most probably a further stage 

 in the absorption of the egg. I was unable, however, to 

 find intermediate stages connecting this condition with that 

 shown in fig. 21. In the latter figure the egg as such has 

 disappeared, its substance having been resolved into fat 

 drops which are contained in the cells of the proliferated 

 follicular epithelium. In fig. 23 the ovigerous pouch is 

 much contracted, being almost flush with the level of the 

 general surface of the ovary. The theca is greatly thick- 

 ened. The egg is represented by a mass of yellow granules, 

 in which are nuclei of doubtful origin and many leucocytes. 

 The granules are apparently not of a fatty nature. Had 

 they been so they would have dissolved out in the prepara- 

 tion of the sections, and represented in the latter by 

 vacuoles. They are probably lutein granules. Such masses 

 of yellow granules were common in certain ovaries of 

 Zoarces. They are always contained within contracted 

 ovigerous pouches, and doubtless each represents an egg. 



The presence of leucocytes in large numbers in association 

 with yellow granules is important. Barfurth considers that 

 leucocytes play only a subordinate part in the degeneration 

 of the eggs of the trout. Ruge (1889), on the other hand, 

 speaks of a simultaneous incursion of blood-cells and fol- 

 licular epithelial cells into the degenerating egg, and he 

 regards both kinds of elements as taking active parts in the 

 breaking down of the egg. I do not find in Zoarces that 

 the blood-cells play any part in the actual fatty degeneration 

 of the substance of the egg. No blood-cells could be seen in 

 the dead egg or amongst the cells of the proliferated follicu- 

 lar epithelium during the fatty degeneration of the egg. 

 The follicular epithelium only is concerned iu this process. 

 Since the membrana propria folliculi may often be seen 

 intact in follicles whose egg-cavity is entirely filled up with 

 the fat-infiltrated tissue of the follicular epithelium as shown 



