OVAEY AND INTRA-OVARIAN EGG IN TELEOSTEANS. 311 



number of eggs in each batch — an interesting provision, by which 

 a fish possessing somewhat bulky eggs can nevertheless extrude 

 an unusually large number, since when all the eggs of the various 

 batches have escaped, many more have swelled to maturity than 

 could possibly have been contained in the ovary if all had to be 

 shed at once, or the batches soon after one another. It seems to 

 me, therefore, that with this condition a resting period must of 

 necessity be at any rate much shorter than in the condition where 

 batches of ova are rapidly extruded one after the other, until all 

 are gone. 



I should, therefore, expect that in all Salmonidse, and fish which 

 get rid of all their eggs at once, a long resting period was inva- 

 riable. The common dab certainly does not get rid of all its eggs 

 at once, yet has a long resting period ; and if similar conditions bring 

 about similar results in other groups, I can have no hesitation in 

 saying that I believe a resting period is usual in Teleosts. 



It may appear that I lay too much stress on this point, but with 

 the diversity of systems of extruding the eggs, the long period 

 during which spawning goes on, and the presence of eggs of more 

 than one generation in the ovary, a resting period has appeared to 

 some to be improbable. 



Whenever the ova escape and the pressure on the ovary is 

 relieved, the fibrous walls contract rapidly ; and as the organ becomes 

 empty, so it is drawn together from every point. The majority of 

 fibres were seen to run longitudinally ; the significance of this now 

 appears, since the greatest reduction in size takes place in the long 

 axis of the organ. 



From the very greatest distension the ovary is speedily reduced 

 to a size almost as small as that seen in the immature condition, the 

 walls being then at their very thickest. 



It was my original intention, in treating of the ovary, to compare 

 the immature organ of the young fish with the resting or inactive 

 condition in the adult ; being of opinion that a decided difference 

 could be demonstrated — a point of vei'y decided importance. 1 

 have, however, decided against taking the matter up in this paper, 

 since, if the subject is treated from a practical fishery point of view, 

 the results can be more forcibly applied to that branch of work, on 

 which it has the most important bearing. 



