n. (Zool.) One of the Lamellibranchia (also called Pelecypoda). Also used adjectively. [ 1913 Webster ]

{ ‖‖ } n. pl. [ NL. See lamella, and Branchia, Branchiate. ] (Zool.) An earlier name for the class of Mollusca including all those that have bivalve shells, as the clams, oysters, mussels, etc., now called Pelecypoda or Bivalvia. [ 1913 Webster +PJC ]

☞ They usually have two (rarely but one) flat, lamelliform gills on each side of the body. They have an imperfectly developed head, concealed within the shell, whence they are called Acephala. Called also Conchifera, and Pelecypoda. See Bivalve. [ 1913 Webster ]

a. (Zool.) Having lamellar gills; belonging to the Lamellibranchia (also called Pelecypoda). -- n. One of the Lamellibranchia (also called Pelecypoda). [ 1913 Webster ]