What is the shipworm?

   The shipworm or teredo is an aberrant or much modified lamellibranch mollusk of the family Teredinidae, so called from being wormlike in general shape and from boring into hulls below their waterline. The animal is several inches to 3 feet in length. The shell itself is much reduced, equivalve, widely gaping, and covers only a part of the animal. The shipworm is a menace to wooden ships.