166 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
the above vessel. On April 6th, 364,250 plaice fry were 
set free on the way to the off-shore grounds between 
Lancashire and the Isle of Man. On April 9th, 90,000 
flounder fry were distributed about the same locality as 
the last, making 3,318,910 in all. 
Besides bringing in the eggs, the steamer also, on 
various occasions, collected numbers of nearly mature 
fish, chiefly plaice and flounders. These were kept alive 
in our tanks, where the eggs were shed as they became 
ripe, and the majority of them were fertilised. The 
emission and fertilisation of these eggs, which always 
took place in the dark, went on in the tanks probably 
much in the same way as under natural conditions in the 
sea. The eggs rose to the surface and were carried along 
by the water, which was allowed to overflow into a floating 
collecting box, where they were retained, and afterwards 
transferred to the hatching apparatus. The subsequent 
incubation of these eggs and hatching out of the larvee was 
accompanied by a much smaller mortality than in the case 
of the eggs obtained by the steamer. The fry hatched 
out from these eggs numbered 78,000 plaice and 90,000 
flounders (included in the 3,318,910). 
When the spawning period of the sole approached, 
special visits were made to the off-shore grounds to collect 
mature fish, which were brought in and kept alive in the 
tanks. In the course of afew days some of them began 
to shed their eggs, which rose to the surface and were 
collected from the overflowing water. On being submitted 
to microscopic examination it was found, however, that 
not a single egg was fertilised. Various attempts were then 
made to bring about fertilisation by dissecting the male 
fish and squeezing up the reproductive organ amongst the 
eggs, but all attempts failed owing probably to the imma- 
turity of the male fish. 
