226 THE WORLD OF THE SEA. 
The third cavity is armed in a peculiar manner with pointed hooks 
bending towards the gizzard. Cuvier could attribute to these no 
other office than that of preventing the food from passing through 
the masticating apparatus too quickly, in order that it might have 
time to be thoroughly crushed. 
By a marvellous compensation, the power of the stomach is 
always in the inverse ratio to the number of teeth the mollusk 
possesses. This organ is powerful in its digesting action when the 
dental apparatus is not very perfect, and on the contrary it is 
weak when the second stomach is well garnished with grinders. 
As in the case of the sea-hare, some of the mollusks, in addition 
to all this complicated apparatus, have their fourth, or stomach 
proper, also provided with solid plates which perform the office of 
teeth. Thus the cavity performs the double function of stomach 
and mouth. 
The aplysie exhale a disagreeable odour. They secrete an 
acrid, limpid humour which has a powerful corrosive action, and 
attacks the hand which incautiously touches them. From the 
edges of their mantle another secretion oozes, which is a liquid 
of a dark colour. This the creature ejects into the water around 
it, thus forming a cloud under the cover of which it escapes the 
threatened danger. 
The ancients regarded the sea-hares as animals of an evil 
omen; and yet they were held in great repute, because they were 
supposed to have a power over the female heart. Apuleius was 
accused of sorcery because he had bought a number of aplysiz 
from a fisherman. He had just married a rich widow; his crime 
was the marriage of the widow, and his principal accuser the 
widow's son. 
The aplysie have respiratory organs which, like those of the 
oysters, are fringes hidden beneath the folds of the mantle. 
Amongst the 7yrzfors—mollusks not unlike the sea-hares—these 
organs are entirely exposed; they stand above the surface in 
little tufts. Cuvier describes one of these creatures, inhabiting 
the French coast, whose colour was a beautiful bronze. Another, 
a native of the Sicilian waters, is still more brilliant, and has found 
a eulogist in M. Quatrefages. Imagine a little snail carrying 
on the ridge of its back a row of very minute shrubs, beautifully 
