the world > animals > invertebrates > subkingdom Metazoa > grade Triploblastica or Coelomata > class Pelecypoda or Conchifera > [noun] > section Asiphonida > family Mytilidae > genus Lithodomus > member of (3)
a date mussel; (also) the shell of this.
a bivalve mollusc that bores into rock or wood; esp. a date mussel.
(see quots. and date-shell n. at date, n.1 compounds 2).