PROCEEDINGS OP THE SOCIETY. 
813 
The cause of this condition is very obscure. The fish affected often 
seem emaciated, but this is by no means always the case, and occurs 
more often where there are very many single eggs and small masses 
than where one large tumour is present. They often seem to be more 
liable to the attacks of Caligus than normal fishes ; but probably both 
of these conditions are due to the same cause, that is, some circumstance 
which renders the flounder more liable than usual to be seized on by a 
parasite, perhaps weakness and want of activity. Certainly there is no 
diseased condition common to all the fish affected in this way. Perhaps 
the fact that such fish are most commonly found near the mouths of 
rivers might suggest the action of a fresh-water parasite, especially as 
flounders ascend rivers for some distance. Day mentions the fact that 
many such are found in the Thames estuary, and while many with this 
disease are caught near the mouths of the Tay and the Forth, I have not 
seen any flounders caught by trawl more than twenty miles from a 
considerable river, affected by this disease. They are commonly found 
on the Danish coast of the Baltic by fishermen, but are apparently not 
known on the south and west coasts of Norway. The plaice is very 
rarely affected in this way ; I have only found two specimens, in each 
case there was a large tumour on the head. 
It is difficult to understand how any animal could force so large a 
mass of eggs beneath the skin of a fish, and yet more difficult to see 
why it should do so. The eggs rarely develope, they are usually kept 
for a long time beneath the skin, perhaps for all the life of the host, 
the interspaces being organized. Indeed the process seems so useless 
to the unknown species to which the eggs belong, that we are driven to 
suppose that eggs laid in masses free in the water adhere in some way 
to the skin of the flounder, that the skin beneath is absorbed, and that 
new skin over the mass and connective tissue between its elements grows 
at the same time, until the whole tumour is formed. And although no 
stage of such a process has been seen, this view appears the more likely 
because of the elongated and even pedunculated form of some specimens, 
because of the parts of the fish to which they are attached, and because 
marks are not found in the skin which would show that the eggs had 
been forced in. 
Yet so improbable does such a view as this seem that until these 
eggs have been hatched out and the species to which they belong 
established, it will be impossible to pronounce a definite opinion on the 
subject. 
On the motion of the President the thanks of the meeting were voted 
to the author. 
The President said it would be remembered that last year about that 
time the Society held a Conversazione ; the Council had decided to hold 
another, but thought it would be better to defer it until their exhibitors 
were better able to obtain a supply of specimens of pond life, which 
always proved so attractive to visitors. Instead, therefore, of holding it 
during the winter they proposed to postpone it until March or April, 
which would enable them to exhibit collections made during the Easter 
holidays. 
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