MOLLUSCA. 15 
refuse to eat those which are dried. We are not aware that 
putrid vegetable matter is consumed by them, although 
many of the snails and slugs are found under putrid leaves 
and decayed wood. In these places there is shelter from 
the sun, together with dampness, so that it is difficult to de- 
termine, whether they sojourn in an agreeable dwelling, or 
a well-stored larder. Those mollusca which are carnivo- 
rous, prey on minute animals in a living state, and many of 
them greedily attack putrid matter. 
The means employed to bring the food within the reach 
of the organs of deglutition, are exceedingly interesting, 
both on account of their variety and success. Some are 
provided with ¢entacula fur securing their prey, and con- 
veying it to their mouth, as the cuttle-fish ; others protrude 
a lengthened probosis, or an extended lip or tongue, as the 
limpet, and thus bring their food into the mouth. By many, 
however, which are fixedtothe same spot during the continu- 
ance of existence, or only capable of very limited locomotive 
power, successful efforts are made to excite currents in the wa- 
ter, whereby fresh portions of itare brought in contact with the 
mouth, and its animal or vegetable contents separated. 
Where part only of any kind of food is taken into the mouth 
at once, the lips are possessed of sufficient firmness to cut 
off the requisite portions, or there are corneous mandibles 
to perform the office. 
In the mouth, there is scarcely any process performed 
analogous to that of mastication, in the higher orders of ani- 
mals. When the food is in the mouth, or entering into the 
gullet, it is mixed with saliva, as in the more perfect ani- 
mals. The salivary glands in which it is secreted, are in 
general of considerable size, divided into lobes, and, in some 
cases, separated into distinct masses. In many species the 
