Source : Webster's Revised Unabridged Dictionary (1913)

Nematocalyx \Nem`a*to*ca"lyx\, n.; pl. {Nematocalyces}, E.
   -{calyxes}. [NL. See {Nemato-}, and {Calyx}.] (Zo["o]l.)
   One of a peculiar kind of cups, or calicles, found upon
   hydroids of the family {Plumularid[ae]}. They contain
   nematocysts. See {Plumularia}.