What is "teredo navalis"

Inclusa \In*clu"sa\, n. pl. [NL., fr. L. inclusus, p. p. of includere to shut in.] (Zo["o]l.) A tribe of bivalve mollusks, characterized by the closed state of the mantle which envelops the body. The ship borer ( Teredo navalis) is an example.

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 of two valves which is specialised to bore through wood.

This species may have originated in the northeast Atlantic Ocean, but has spread around the world. It tunnels into underwater piers and pilings and is a major cause of damage and destruction to submarine timber structures and the hulls of wooden boats.