Great Shipworm

Teredo navalis, the naval shipworm, is a species of saltwater clam, a marine bivalve mollusc in the family Teredinidae, the shipworms. This species is the type species of the genus Teredo. Like other species in this family, this bivalve is called a shipworm, because it resembles a worm in general appearance, while at the anterior end it has a small shell with two valves which are specialised at boring through wood.