The Onchidiidæ are described as agnathous, but I am confident of having observed the jaw figured.
The mouth is a transverse slit, which shows no teeth, nor any jaws properly so called, and therefore affords an apparent support to the agnathous theory of the Ostracodermi.
Wikipedia foundation.
agnathous — adj. [Gr. a, without; gnathos, jaw] Lacking a jaw … Dictionary of invertebrate zoology
agnathous — /ag neuh theuhs/, adj. Zool. 1. having no jaws. 2. belonging or pertaining to the class Agnatha. Also, agnathan, agnathic. [1875 80; see AGNATHA, OUS] * * * … Universalium
agnathous — Relating to agnathia … Medical dictionary
agnathous — adj. having no jaws; (Zoology) belonging to the family Agnatha (jawless vertebrates) … English contemporary dictionary
agnathous — ag·na·thous … English syllables
agnathous — a. lacking jaws. ♦ agnathia, n … Dictionary of difficult words
agnathous — … Useful english dictionary
Hagfish — For the punk rock band, see Hagfish (band). Hagfish Pacific hagfish resting on the ocean bottom, at 280 m depth off the Oregon coast. Scientific classification Kingdom … Wikipedia
agnathan — /ag neuh theuhn/, n. 1. any member of the vertebrate class Agnatha. adj. 2. agnathous. [AGNATH(A) + AN] * * * ▪ fish Introduction any member of the group of primitive, jawless fishes (fish) that includes the lampreys (lamprey) (order… … Universalium
vertebrate — /verr teuh brit, brayt /, adj. 1. having vertebrae; having a backbone or spinal column. 2. belonging or pertaining to the Vertebrata (or Craniata), a subphylum of chordate animals, comprising those having a brain enclosed in a skull or cranium… … Universalium
