PLATE III. 
TEREDO NAVALis. 
Teredo navalis. Lam. Syst. v. p. 440. — Mont. Test. Brit. p. 527 — Donov. Brit. Sh. pi. 145. — Mat. and Rack, 
in Lin. Tr. viii. p. 449. 
This shell was long considered by naturalists as a simple tube ; but it has since been discovered that, at the 
smaller end, it has two minute valves, which are attached to the head of the animal, and are of a hemispheric 
form, somewhat projecting in front, pointed and longitudinally striated. 
This species is well known to mariners by the name of the Ship- Worm, from its burrowing in the bottoms of 
ships, and other timber which remains any length of time under water. This destructive animal was first in- 
troduced by vessels from tropical climates, and has now become naturalized to our temperate region ; and is 
common in Plymouth dock, and the East and West India docks on the Thames. Piles of the hardest oak sel- 
dom last more than four or five years in places where this shell inhabits. 
