67 
and has come to the result that these young fishes seek the Cyanea 
exclusively with the object of feeding on its ovaries and tentacles, 
it being thus a case of parasitism, not of.symbiosis. The same was 
found to hold good also for the young Caranw. A fairly complete 
review of the litterature concerning the subject is given in this 
paper. 
During my Expedition to Siam in 1899—1900 I made a good 
deal of observations about this habit of young fishes; as no record 
thereof has been published in any scientific paper (only a popular 
account, danish, in ,,Dansk Fiskeriforenings Medlemsblad”, 1901, 
p. 134-—136) I may include an account of them in this paper. 
Under the leaves floating in the surface very often were found 
Young fishes, sometimes also small Cephalopods. One day, in calm 
weather and burning sun a piece of driftwood came drifting; a 
large shoal of fishes was seen under it; when chased away they 
always came back again. Another day, likewise calm weather and 
burning sun, a cocoanut came drifting along the boat; when tak- 
ing it out of the water I found a rather large fish to hide itself 
under it. It was quite bewildered, when its shelter had disappeared ; 
we had time to tack the boat and come up again to the place 
and could then easily take it up with a handnet. Under a quite 
transparent jellyfish that was very common no fish was ever seen 
and not under the Salpæ either. Any number of young fishes could 
be taken in this way, when it was sunshine; on the other hand, 
when the weather was dark, hardly one was ever found in this way. 
The conclusion from these observations evidently is this, that 
it is in order to find a shelter, perhaps especially from the strong 
"light, that the young fishes collect under the jellyfishes a. 0., not in 
Order to find food. That they may feed on the animals caught by 
the tentacles of the jellyfishes, or on the jellyfishes themselves, as 
do Gadus merlangus and Caranx I have no intention to deny, but 
if this were the real object of their gathering under the jellyfishes, 
one should expect to find them under the quite transparent jelly- 
fishes as well and in dark weather as well as in sunshine. Ås I 
said in the popular account quoted: ,The reason why they seek 
this place is undoubtedly that they seek shadow, and then it is 
Otherwise the same to them, whether it be a leaf, a jellyfish, a 
Cephalopod shield, a turtle or a cocoanut, if it be only something 
