the Slug, or Naked Snail; a genus of insects, belonging to the order of vermes mollusca; the characters of which are these: The body is oblong, fitted for crawling, with a kind of muscular coat on the upper part; and the belly is plain: they have a roundish hole in the side, near the neck, which serves for the purpose of genitals, and for voiding their excrements. They have likewise four tentacula, or horns, situated above the mouth, which they extend or retract at pleasure. There are eight species, distinguished entirely by their colour; as the black flag, the white flag, the reddish flag, the ash-coloured flag, &c. The last of these, the agrestis or field-flag, is very common in gardens, and destructive to plants. They are sometimes swallowed by consumptive persons, to whom they are thought to be of service. Snails are said to be hermaphrodites, and mutually to impregnate each other. See Reproduction.