24 



through; for plaice 10 mm loog are very slender, and can go through auy 

 net knit with a needle like a commou tishingnet. 



I have here mentioned which purely biological conditioas it would be 

 of interest to have investigated witli respect to the fry and eggs of the 

 plaice. But it is auother question whether we have not here entered a field 

 of research which, by a very iutiraate co-operation of biologists and hydro- 

 graphers, might give us a greater aud deeper understanding of these mat- 

 ters. By a minute study of the specific gravity of the eggs uuder different 

 pressures and different temperatures, together witli a close study of the 

 movement of the masses of water, particularly with a view to the occur- 

 rence of the eggs, we must be able to get more information; and so I 

 leave this matter to botii hvdrographers and biologists for f urther consideratiou. 



