What is "lithodomus"

Lithodomus \Li*thod"o*mus\, n. [NL. See Lithodome.] (Zo["o]l.) A genus of elongated bivalve shells, allied to the mussels, and remarkable for their ability to bore holes for shelter, in solid limestone, shells, etc. Called also Lithophagus.

Note: These holes are at first very small and shallow, but are enlarged with the growth of the shell, sometimes becoming two or three inches deep and nearly an inch diameter.