Meconidium \Mec`o*nid"i*um\, n. [NL., dim. of Gr. ? a poppy. So
called in allusion to the shape of the seed capsules of the
poppy.] (Zool.)
A kind of gonophore produced by hydroids of the genus
{Gonothyraea}. It has tentacles, and otherwise resembles a
free medusa, but remains attached by a pedicel.
[1913 Webster]