OVABY AND OVAlilAN OVA IN CERTAIN MAlJlNIi FISHES. 121 



the eggs of this kind the protoplasm has separated from the 

 germinal vesicle, leaving a space containing scattered granules, 

 and in some cases the germinal vesicle is absent altogether, 

 having been washed away in the process of preparation. But 

 where it is present it shows the usual structure, having a 

 distinct membrane, on the inner side of which are the nucleoli. 

 In many of these eggs the vitelline nucleus is very distinct, 

 situated at the periphery of the protoplasm. 



The remaining eggs are in a remarkable condition, which is 

 illustrated in fig. 19. The shape is variable. T)ie remains of 

 the egg are seen forming a shrunken dense mass within the 

 follicle. The mass is more deeply stained than the eggs in 

 the condition previously described, and less granular in appear- 

 ance. Within the mass is a more translucent area containing 

 a single nucleolus. The nucleoli of the healthy condition 

 have apparently fused together, and the germinal vesicle has 

 degenerated. On the outside of the mass can be seen a 

 shrunken and crumpled membrane, evidently the membrane 

 of the ovum which had begun to form at the time when the 

 maturation was arrested. Within the wall of the follicle is 

 seen a distinct granular lining with nuclei here and there, but 

 no definite cell outlines. This I take to be the follicular epithe- 

 lium in a degenerating condition, although it is thicker and 

 more distinct than in either of the conditions previously de- 

 scribed. In the walls of the follicle are seen fibres of connec- 

 tive tissue and nuclei. There can be no doubt that these 

 structures are the opaque dead eggs, or " masses " seen in 

 examination of the fresh material, and it is evident that the 

 egg having reached the stage of maturation at which yolk 

 formation commences, has died, and forms within its follicle a 

 contracted opaque mass which is undergoing a process of 

 absorption. 



That the condition of the germinal vesicle seen in these 

 aborted eggs in prepared sections is not artificially produced 

 by the process of preparation is proved by the fact that the 

 same condition has been observed in aborted eggs in the fresh 

 state. In fig. 20, PI. 3, is shown the appearance presented 



