Source : Webster's Revised Unabridged Dictionary (1913)

Somatocyst \So"ma*to*cyst\, n. [Gr. sw^ma, sw`matos, body +
   ky`stis a bladder.] (Zo["o]l.)
   A cavity in the primary nectocalyx of certain Siphonophora.
   See Illust. under {Nectocalyx}.