\Pol`y*gor"di*us\, n. [NL. See {Poly-}, and
{Gordius}.] (Zo["o]l.)
A genus of marine annelids, believed to be an ancient or
ancestral type. It is remarkable for its simplicity of
structure and want of parapodia. It is the type of the order
Archiannelida, or Gymnotoma. See {Loeven's larva}.