34 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



the bottom, and changing their mode of life from the 

 pelagic larval one, where the food is Copepoda and other 

 surface organisms, to that of the gronnd-living adult, 

 feeding on shellfish and worms. 



When floating on the surface as eggs, in the 

 embryonic stages and as larvae, they are the natural prey 

 of innumerable organisms around them, from medusae to 

 fishes ; and it cannot be doubted that the destruction must 

 be very great, especially in the younger stages. The 

 post-larval forms seem better able to avoid enemies and to 

 take care of themselves ; while when the metamorphosis 

 has taken place, they are probably safe from many dangers 

 which threatened them in the earlier periods. Conse- 

 quently, protection in a hatchery must save a very large 

 proportion of the eggs and larvae from what would 

 otherwise be their natural fate. 



During the present hatching season we have set free 

 our plaice larvae when between a week and a fortnight 

 after hatching, our object being to keep them as long as 

 possible so as to protect them from destruction in the sea, 

 but to let them out before the yolk-sac was all absorbed 

 and external food required. 



No doubt it would be still better if we could safely 

 keep them longer, see them through the period of 

 metamorphosis, and set them free in our bays as young 

 flat-fish. That natural sequel to artificial hatching, viz., 

 rearing the young fish in captivity, will no doubt come; 

 and we are now experimenting in the matter by allowing a 

 certain number of the larvae to remain developing in 

 our spawning pond. It is satisfactory to find 



that these are passing through the post-larval 

 period, and are undergoing their metamorphosis. 

 Some have already been seen at the shallower 

 side of the pond as fully formed young flat-fish, 



