Nectocalyx \Nec`to*ca"lyx\, n.; pl. {Nectocalyces}. [NL., fr.
Gr. nhkto`s swimming + ? a calyx.] (Zool.)
(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.
[1913 Webster] Nectosac