• Webster's Revised Unabridged Dictionary
    • n Meconidium (Zoöl) A kind of gonophore produced by hydroids of the genus Gonothyræa. It has tentacles, and otherwise resembles a free medusa, but remains attached by a pedicel.
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Century Dictionary and Cyclopedia
    • n meconidium The fixed generative medusoid of some calyptoblastic hydroids, as of the genus Gonothyrea, in which the sexual elements are matured and from which the embryos are discharged in the form of ciliated planulas. These generative buds or zoöids develop upon the gonotheca, several in succession from above down ward, retaining their direct communication with the blastostyle; when fully matured they are sacs hanging to the gonotheca by a narrow stalk or peduncle, having an opening or mouth at the far end surrounded by a circlet of tentacles, through which mouth the ova escape; the cavity of the hollow meconidium communicates with that of the blastostyle, and the medusoid, after performing its function, decays upon its stem, never becoming detached as a free zooid.
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Webster's Revised Unabridged Dictionary
NL., dim. of Gr. a poppy. So called in allusion to the shape of the seed capsules of the poppy