agnathic

Mouth is without jaws (agnathic) in lampreys and hagfishes and bounded by jaws (gnathic) in all other vertebrates.

2004, V. B. Rastogi, Modern Biology, seventh edition, Pitambar, →ISBN, page II-61

Mortal combat and decapitation are suggested by the eight skillfully and gracefully engraved heads depicted here with their serrated necks, the prominent arrowheads, and the agnathic or jawless head regalia.

2004, David H. Dye, “Art, Ritual, and Chiefly Warfare in the Mississippian World”, in Hero, Hawk, and Open Hand, Art Institute of Chicago, →ISBN, page 201

In the mouth: various irregularities, such as wide separation of the teeth; abnormal development of the canines; the prognathic or agnathic jaw; high arching of the palate; cleft palate—all are found more frequently among persons otherwise degenerate than in normal individuals.

1913, John H. Musser, A Practical Treatise on Medical Diagnosis for Students and Physicians, 6th edition, Lea & Febiger, page 87

Most pregnancies with agnathic fetuses are associated with polyhydramnios, which probably result from fetal inability to swallow because of persistence of the oropharyngeal membrane.

2006, Karen Gripp, Luis Fernando Escobar, “Facial Bones”, in Human Malformations and Related Anomalies, 2nd edition, Oxford University Press, →ISBN, page 287