||Ser"pu*la (?), n.; pl.
Serpulæ (#), E. Serpulas
(#). [L., a little snake. See Serpent.] (Zoöl.)
Any one of numerous species of tubicolous annelids of the genus
Serpula and allied genera of the family Serpulidæ.
They secrete a calcareous tube, which is usually irregularly
contorted, but is sometimes spirally coiled. The worm has 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.