Sea slug is a common name used for several different groups of saltwater snails that either lack a shell or have only an internal shell. It is a paraphyletic name used for various lineages of marine gastropod mollusks that are either not conchiferous (shell-bearing) or appear not to be.
The phrase "sea slug" is often applied to nudibranchs (many members of which are colorful and are a noticeable part of the underwater fauna), sea hares, the sacoglossans, various families of bubble snails (Cephalaspidea), the sorbeoconch family Pterotracheoidea, the pulmonate (air-breathing) sea slug family Onchidiidae, and others.
Read more about Sea Slug: Reproduction
Famous quotes containing the words sea and/or slug:
“Another success is the post-office, with its educating energy augmented by cheapness and guarded by a certain religious sentiment in mankind; so that the power of a wafer or a drop of wax or gluten to guard a letter, as it flies over sea over land and comes to its address as if a battalion of artillery brought it, I look upon as a fine meter of civilization.”
—Ralph Waldo Emerson (1803–1882)
“Adrift dissolving, bound for death;
Though lumpish thou, a lumbering one—
A lumbering lubbard loitering slow,
Impingers rue thee and go down,
Sounding thy precipice below,
Nor stir the slimy slug that sprawls
Along thy dead indifference of walls.”
—Herman Melville (1819–1891)