MOLLUSCA

Mollusca, phylum Mollusca

(noun) gastropods; bivalves; cephalopods; chitons

Source: WordNet® 3.1

Mol*lus"ca, n. pl. Etym: [NL. See Mollusk.] (Zoöl.)

Definition: One of the grand divisions of the animal kingdom, including the classes Cephalopoda, Gastropoda, PteropodaScaphopoda, and 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.

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 Molluscoudea.

MOLLUSCUM

Mol*lus"cum, n. Etym: [NL. See Mollusk.] (Med.)

Definition: A cutaneous disease characterized by numerous tumors, of various forms, filled with a thick matter; -- so called from the resemblance of the tumors to some molluscous animals. Dunglison.

Source: Webster’s Unabridged Dictionary 1913 Edition