Caranx and a Crambessa. 269 
division ; and, on the other hand, the fish only lodges itself 
in a natural cavity of the Medusa—a cavity which has nothing 
to do with the digestive or gastrovascular system. This 
cavity is widened by the prolonged use which the fish has 
made of it, and nevertheless the Crambessa is perfectly unin- 
jured—an evident proof that the fish regards its associate as a 
place of refuge and not as a prey. 
Surprised at the singularity of this fact, I wrote to M. de 
Robillard to ask him for some details upon the subject. The 
following is the reply that I received from him :—‘* The facts 
to which I called your attention with regard to the little fish 
which follows the anemone and constantly enters into it with- 
out quitting it is perfectly correct ; the fisherman who brought 
them to me captured them together. I can personally certify 
the fact. It is some years since, being on the quay of our 
port, I observed the same thing ; it was also the same species 
of fish as that which I sent to you which entered into the 
anemone and issued from it ; and as this took place at about 
6 inches under water, it was very easy to observe what went 
on. The fish was alone, there were no others. What ex- 
planation is to be given of this phenomenon? {Is it that the 
fish finds something to eat in the anemone which induces it 
to pursue and penetrate into it? I cannot say: the anemone, 
although receiving the fish, is alive, and one sees it move. 
You should verify the interior of the anemone to see that nothing 
has been destroyed by the fish.” 
Lastly, having requested M. de Robillard to endeavour to 
procure for me, if possible, some specimens of the two animals 
in question, I received from him, while I was engaged in 
preparing these notes, a letter, dated July 15, 1883, announ- 
cing a fresh consignment of objects for the Museum, and 
further a tin box containing two Medusz, each with its little 
fish; he had received them in sea-water, the fishes and 
Meduse all living. I do not know how it came about that, 
unfortunately, all the objects announced were in the case ex- 
cept the box with the Meduse ; I suppose that M. de Robil- 
lard forgot to put them in. 
Leaving on one side, then, all the hypotheses hitherto put 
forward about Medusz eating small fishes and small fishes 
eating Meduse, I arrive at the following conclusion, corrobo- 
rated by the fact which I have pointed out, namely, that there 
are certain species of fish of which the adults live at more or 
less considerable depths, and of which the young, compelled 
either by some undetermined peculiarity of their organization 
or by the necessity of seeking food better suited to their age, 
come up to seek certain Medusz at the surface of the sea. It 
