MOLLUSCA. 31 
selecting and retaining such substances as are 
suitable for digestion. 
The remaining classes divide themselves into 
flesh-eaters, and those which live upon vegetable 
diet, the preponderance, however, being, as well as 
ean be estimated, rather with the former. Not 
a few of the Univalves feed upon their Bivalve 
relatives, not seizing the opportunity, as has been 
pretended, of killing their victim as it lies in- 
cautiously with gaping shells; but by drilling 
a small hole through one of the valves, and ex- 
tracting the fleshy parts, particle by particle. 
Some species devour dead fishes and other putri- 
fying animal matters with avidity. Many of the 
elegant naked-gilled tribes prey on each other, 
though their proper food consists of zoophytes. 
I have found the large Holis papillosa tear away 
the tentacles of different species of sea-anemones, 
which seemed to be its natural food. 
The Cephalopoda, including the Cuttles, the 
Poulpes, and the Squids, are fierce and predatory, 
the tyrants of the deep. Furnished with many long 
arms, stretching in all directions, and studded with 
rows of adhesive suckers, they seize with ruthless 
grasp any passing fish or other animal, whose 
strength is inferior to their own, and drag it toa 
hard and sharp horny beak, the mandibles of which 
_ resemble those of a parrot’s bill, and being moved 
by powerful muscles are enabled either to crush 
the shells in which their victim may be enclosed, 
or to tear it to pieces if it be a fish, or other animal 
of muscular or sinewy tissues. 
In speaking of the vegetable-feeding Mollusca, the 
ravages committed by those pests of our gardens, 
the Slug and Snail, will occur to every one. Other 
