(zoology) Any of numerous species
of tubicolous annelids
of the genus Serpula
and allied genera of the family
Serpulidae that secrete a calcareous tube, usually irregularly contorted, but sometimes spirally coiled, with a wreath of plumelike and often bright-colored gills around its head, and usually an operculum
to close the aperture of its tube when it retracts.