Nematocalyx (?), n.; pl. Nematocalyces (#), E. Nematocalyxes (#). [NL. See Nemato-, and Calyx.] (Zoöl.) One of a peculiar kind of cups, or calicles, found upon hydroids of the family Plumularidæ. They contain nematocysts. See Plumularia.[1913 Webster]