agnathous

adjective2

1. •
   Jawless.

   • The Onchidiidae are described as agnathous, but I am confident of having observed the jaw figured. — 1876
2. •
   Afflicted by or characteristic of agnathia.

   • Dr Underhill exhibited an agnathous and hydrocephalic foetus. This was an instance of the rare abnormality due to defect of the lower jaw. — 1886