echiuroid

noun

1. A worm of the order Echiuroidea.

   “Descriptions of echiuroids based on external characters or on a very summary enumeration of a few internal features have made it difficult to determine the generic position of a number of described forms.”

   “Despite the resemblances of echiuroids to annelids and to sipunculids, the embryological studies of Newby (1940) on Urechis, together with other evidence, seem to indicate that echiuroids are closer to annelids than they are to molluscs.”

   “Generally echiuroids are sedentary, remaining in their holes or burrows and extending the proboscis to feed.”