of the Fishery Board for Scotland. 



149 



Is there any transformation of inorganically-bound phosphorus into 

 ^organically -bound during maturation ? 



In the unripe haddock ovum 24*47 per cent, is in inorganic form, 

 the rest organically-bound ; while in the ripe haddock ovum 21*22 per 

 cent, is in inorganic form, the rest in organic combination. That is to 

 say, in the unripe ovum there is more inorganic phosphorus than in the 

 ripe ovum, but the difference is, comparatively speaking, a small one. 

 What is of far greater importance is the fact that much the larger pro- 

 portion is in organic form in both cases, and hence more suitable for 

 assimilation. 



There are two constituents of the ovum which I have not yet 

 referred to, or only incidentally, and those are the fat and lecithin. 

 Both are present in all the Teleostean ova that I have examined, but the 

 amounts differ. 



As an example of the class which contains no oil-globule in the yolk, 

 the plaice may be taken, while the ling may be taken as characteristic of 

 the class which does contain such an oil-globule. 



The amounts of fat and lecithin in Teleostean ova, and their 

 significance, I shall leave over for discussion in another paper, as the 

 results which I have arrived at are not conclusive. 



Shortly summed up, the changes that occur during the maturation 

 of pelagic and demersal ova are : — 



(1.) Increase in volume. 



(2.) Clearing up of yolk, with disappearance of germinal vesicle. 



(3.) Diminution in specific gravity. 



(4.) Increase in percentage of water. 



(5.) „ chlorides. 



(6.) „ total solids — albumin, etc. 



(7.) . phosphorus — -mainly organically bound. 



(8.) Changes (within the ovum), probably of the nature of conden- 

 sations of most of the organic substances secreted into the 

 vitellus, by means of which complex organic bodies are 

 formed. Probably there is also a transformation of some of 

 the inorganic into organically-bound phosphorus. 



(9.) A transformation of less diffusible into more diffusible bodies. 



Nature and Composition of some of the Ovarian Fluids. 



It is of importance in the investigation of the nature of the matura- 

 tion process to know the composition of the ovarian fluid, hence I have 

 made some analyses which may help to elucidate some points. The 

 fluid was obtained from the roe by allowing the fluid to drain through 

 muslin. The specific gravity was estimated in the first place, and was 

 always found to be distinctly lower than that of the ova. The reaction was 

 almost always neutral. In Lophius, however, and in the roes of some 

 •demersal varieties, it was found to be acid. 



There are three constituents of the fluid which require to be 

 specially considered, viz. : — 



(1.) The albumins. 

 (2.) The chlorides. 



(3.) An organic phosphorus-holding proteid similar to that present 

 in the vitellus. 



