monotreme

  1. Noun.  (zoology) A mammal that lays eggs and has a single urogenital and digestive orifice. Only the echidnas and platypuses are included in this group.
  2. Adjective.  (palynology, of a pollen grain) Having a single trema, or aperture.

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This entry was last updated on RefTopia from its source on 3/20/2012.