MolluscoideaMol`lus*coi"de*a\, n. pl. [NL. See Mollusk, and -oid.] (Zo["o]l.) A division of Invertebrata which includes the classes Brachiopoda and Bryozoa; -- called also Anthoid Mollusca. Note: Originally the Tunicata were included under Molluscoidea, from which they are known to differ widely in structure and embryology. Molluscoidea were formerly considered a subdivision of Mollusca, but they are now known to have more relationship with Annelida than with Mollusca.