OX CRUSTACEA. 
287 
sion would indicate, or rather clearly announce, that Aristotle 
had not himself observed the fact which he relates, or that he 
would testify some uncertainty on the point. 
Pliny has confounded, under the common name of pin- 
notheres, the paguri, and the species of our genus pinnotheres, 
properly so called. 
We must not apply, as some authors have done, to these 
last Crustacea, a passage of Appian, in his Halieutics, in 
which he relates that the crab, when the oyster comes to open 
its shell, puts a stone between the two valves, so that it cannot 
close, and he thus penetrates into it with facility, and devours 
its inhabitant. In another passage, which directly concerns 
the pinnotheres, Appian does not explain himself respecting 
the habits of these animals, in a manner different from that of 
his predecessors. 
Hasselquist, in his voyage to the Levant, says, respecting 
his pinna muricata, that the cuttle-fish is the most irrecon- 
eileable enemy of the molluscum, which inhabits this shell. 
But, happily for it, there are always inside, one, or several 
crab-fish, which remain at the entrance of the shell when the 
animal opens it, and give warning to it to close on the ap- 
proach of the cuttle-fish. 46 Thus,” continues he, 44 the pinna 
permits, in compensation, the crab to reside within its shell.” 
We may well believe that this crustaceum has no need of such 
permission to establish itself there, and that the quick move- 
ments which it makes to withdraw itself from the danger by 
which it is also threatened, are sufficient to frighten the animal 
of the pinna, and induce it to keep its shell close. This crab- 
fish of Hasselquist is probably a species of salicoque, (< cari - 
dion) or pinnophylax, considered in the same light as the 
ancients considered it. Linnaeus, after the authority of his 
disciple, but from very vague information, at first ranged this 
crustaceum in his division of cancri macrouri , but subse- 
quently, whether he wished to omit it as a species too uncer- 
