Agnatha
Pronunciation: /agˈneɪθə/
plural noun
Zoology- a group of primitive jawless vertebrates which includes the lampreys, hagfishes, and many fossil fishlike forms. Compare with cyclostome.
- Superclass Agnatha: the living forms are in the classes Myxini (hagfishes) and Cephalaspidomorphi (lampreys)

Origin:
from modern Latin Agnatha, from a-1 'without' + Greek gnathos 'jaw'