\Nec`to*ca"lyx\, n.; pl. {Nectocalyces}. [NL., fr.
gr. ? swimming + ? a calyx.] (Zo["o]l.)
(a) The swimming bell or umbrella of a jellyfish of medusa.
(b) One of the zooids of certain Siphonophora, having
    somewhat the form, and the essential structure, of the
    bell of a jellyfish, and acting as a swimming organ.