356 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



above is to carry small floating objects in an easterly and 

 northerly direction. Thus eggs and embryos floating at 

 the surface on the spawning ground to the South-east of 

 the Isle of Man will travel easterly with a slight drift to 

 the North to Morecambe Bay, the estuary of the Duddon 

 and to the Cumberland coast. It is also evident that the 

 young fish inhabiting the shallow waters further South, 

 that is in the Ribble and in Liverpool Bay and the Che- 

 shire coasts, must have originated elsewhere than in the 

 spawning grounds referred to. Mr. P. L. Ascroft informs 

 us that from his experience of the drift of floating 

 wreckage it is probable that fish spawning far South in 

 Cardigan Bay and off the Welsh coast generally produce 

 the young fish in the southern and central portions of the 

 Lancashire coast. Up to the present time the spawning 

 areas off the Welsh coast have not been investigated. 



This first pelagic stage of the young Plaice is the 

 period during which both embryonic development and 

 larval metamorphosis take place. Up to the time when 

 the rotation of the eyes is fairly in progress the young fish 

 swims freely in the upper layers of the sea, and during 

 that change it gradually sinks until, when metamorphosis 

 is completed, it finally settles on the bottom. It is gene- 

 rally agreed that the young Plaice during this change 

 cannot, or at least does not, inhabit the sea at any great 

 depth. It is probable therefore that should the larva? 

 begin to sink while still in deep water their destruction 

 follows, and it seems essential that they should have nearly 

 completed their larval changes not earlier than the time 

 when they arrive at the shallow coastal waters. About 30 

 days after hatching the larvae seek the bottom and this 

 gives a period of over 40 days for them to complete their 

 inshore drift from the spawning grounds. 



During this drift inshore the embryos and larva? are 



