hyperoartia

from The Century Dictionary.

• A primary subdivision of myzonts, marsipo-branchiates, or Cyclostomata, including forms with the roof of the mouth or palate entire or imperforate, the single nasal duct not penetrating it.

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

• noun plural (Zoöl.) An order of marsipobranchs including the lampreys. The suckerlike moth contains numerous teeth; the nasal opening is in the middle of the head above, but it does not connect with the mouth. See cyclostoma, and lamprey.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun lampreys as distinguished from hagfishes