300 OVARY AND INTEA-OVARIAN EGC4 IN TELfiOSTEANS. 



and nucleoli. When the ova are in this condition the ovary is 

 in process of being reconstructed. With the process of spawn- 

 ing the lamellae have been ruptured and the stroma scattered. 

 With the inward growth of the supporting tissue which will 

 be treated of later, the eggs which are at a future period to 

 follow those which have already been extruded are being collected 

 into new lamellae. The flaccid and utterly empty condition of 

 the ovary, as seen in the sections of the spent organ, has to be 

 overcome. By means of a fairly complete series of slides I 

 have been able to follow through this stage, and conclude that 

 this condition of protoplasmic separation in the ovum has a sig- 

 nificance not so much connected with the development of the 

 ovum itself as with the building up of the trabeculse of the ovary. 



A circular separation of the protoplasm in the egg of fishes has 

 been noticed by Eimer (3) as far back as 1872, and a similar arrange- 

 ment has been commented upon in reptiles, molluscs, and insects by 

 other authors. To account for it various suggestions have been 

 made. The dark ring must either take its peculiar property from 

 some outside tissue, or stain darkly because it has received matter 

 from the nucleus. Will, in treating of Orthoptera, (4) describes the 

 disappearance of the nuclear membrane and the migration of nucleoli 

 to the surface of the ovum, forming in this way a follicular epithe- 

 lium. Scharfi also (loc. cit.) notices the presence of a few nucleoli 

 outside the nuclear membrane of Gadus virens, and assigns the 

 peculiar property of this darkly stained layer to the presence of 

 nuclear substance. 



The clear protoplasmic portion seems to have attracted less atten- 

 tion, and to be generally considered as the normal unchanged proto- 

 plasm of the egg. So far as I know, the ultimate history of the clear 

 and dark layers has not been traced to its issue. 



In sections treated in the usual way the dark portion often 

 becomes rather opaque for good observation, the staining having 

 a distinct resemblance to that seen in the colouring of nucleoli. 

 Nevertheless at this particular stage I have not, in the common 

 dab, been able to detect the presence of nucleoli outside the 

 nuclear membrane, although those bodies have been sufiiciently 

 apparent in this position at other stages. ScharfE says that he saw 

 these nucleoli occasionally in the dark layer, but never, except in 

 the case of Hippoglossoides, at the surface of the egg. The explana- 

 tion may probably be that in different species the nucleoli are 

 given off at different times, and that in the case of the common dab 

 this process takes place previous to the differentiation of the areas. 

 1 find that the light protoplasm soon splits off from the dark. 



Fig. 1 shows this process. The egg seems to increase rapidly in 



