[W/K] :: Mollusca

  Mollusca \Mol*lus"ca\, prop. n. pl. [NL. See Mollusk.] (Zool.)
     One of the grand divisions of the animal kingdom, a phylum
     including the classes Cephalopoda, Gastropoda, Pteropoda,
     Scaphopoda, and Pelecyopoda (syn. Bivalvia, formerly called
     Lamellibranchiata, or Conchifera). These animals have an
     unsegmented bilateral body, with most of the organs and parts
     paired, but not repeated longitudinally. Most of them develop
     a mantle, which incloses either a branchial or a pulmonary
     cavity. They are generally more or less covered and protected
     by a calcareous shell, which may be univalve, bivalve, or
     multivalve.
     [1913 Webster +PJC]
  
     Note: Formerly the Brachiopoda, Bryzoa, and Tunicata were
           united with the Lamellibranchiata in an artificial
           group called Acephala, which was also included under
           Mollusca. See Molluscoidea.
           [1913 Webster]

  Mollusca
       n : gastropods; bivalves; cephalopods; chitons [syn: phylum
           Mollusca]