Entry 1 sense Webster, 1913 Myxocystodea · Myx·o·cys·to·de·a · IPA 01 n. pl. A division of Infusoria including the Noctiluca. See Noctiluca. 1. A division of Infusoria including the Noctiluca. See Noctiluca.(Zool.) See: Noctiluca