gephyrea

from The Century Dictionary.

• One of the numerous primary groups of the great division Vermes, or worms, including marine vermiform animals without distinct external segmentation, parapodia, or calcareous skeleton.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) An order of marine Annelida, in which the body is imperfectly, or not at all, annulated externally, and is mostly without setæ.