A mollusc of unusual shape, whose scientific name is the Teredo. It looks like a worm, being long and slender in body. It bores with its cutting shell into wood, and often so riddles ship timbers with holes that they crumble at a touch. At one time these animals destroyed the piles which protected Holland from the sea, and a deluge was averted only by great labor and expense. They make long tunnels in wood which never break into one another.