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 can 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 incautiously with gaping shells; but by drilling a small hole through one of the valves, and extracting the fleshy parts, particle by particle. Some species devour dead fishes and other putrifying 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 Eolis 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 to a 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
