268 M. G. Lunel on Commensalism of a 
turn are pursued by larger pelagic fishes, such as Tunnies 
and other Scombroids.” 
Prof. H. Fol has given to the Museum of Geneva two indi- 
viduals, one of them very young, of Schedophilus meduso- 
phagus, which he collected in the Bay of Messina at the time 
when he was devoting himself to the study of the lower animals 
of the Mediterranean. This naturalist has also seen these 
fishes swimming about Meduse; but he has never observed 
that this was for the purpose of feeding upon them, nor did 
he see the Meduse prey upon the fishes. Dr. Fol therefore 
does not believe that the Medusz could eat fishes, however 
small: these Acalephe, whose organization is so simple and 
so feeble, do not possess digestive organs powerful enough to 
digest a prey so firm. The Actinia even, in which the tissues 
and the organs of digestion are better formed and developed 
than in the Medusaria, often only partially digest the small 
fishes and other little animals which they may capture, and 
reject the parts which are somewhat hard. 
The following observations may furnish, at the same time, 
some interesting data as to the habits of certain species of 
fishes, and an explanation, perhaps more conclusive than that 
which has hitherto been given, of their manceuvres with re- 
spect to the Meduse. 
In a consignment of objects from the Mauritius sent to the 
Museum of Geneva by M. de Robillard, in May 1882, there 
were united and preserved in spirit a Carana melampygus, C. 
& V.*, and a Crambessa palmipes, Hiick.t. The former of 
these animals was fixed by the greater part of its body in the 
apertures formed by the four columns which unite the stomach 
to the umbrella in the latter, and are traversed by canals 
serving to establish a communication between the stomachal 
cavity and the rest of the gastrovascular system . 
All the hypotheses which tend to explain the association of 
fishes and Meduse by assuming that one of these animals 
seeks the other as prey and for food are evidently inadmis- 
sible in the case now before us; for the Medusa belongs to 
the family Rhizostomez, and consequently has no buccal 
aperture properly SO called, but only a series of microscopic 
pores which enable it to absorb food only in a state of extreme 
* Hist. Nat. des Poissons, 1833, tome ix. p. 116. 
+ System der Medusen, 1880, Bd. i. 2nd part, p. 620, 
¢ Iam indebted to the kindness of Dr. H. Fol for the determination of 
this Medusa, at least so far as he could make it with certainty, for the 
yery indifferent state of preservation of the specimen did not enable him to 
count the lebules of the margin of the umbrella, which are no longer 
visible. I may add that Hackel described Crambessa palmipes from 
specimens coming from the northern coast of Australia. 
