1) Agnathan 2) Cousins of eels 3) Fish 4) Jawless fish 5) Jawless vertebrate 6) Slime eels 1) Eptatretus 
Hagfish, the class Myxini (also known as Hyperotreti), are eel-shaped, slime-producing, marine fish (occasionally called slime eels). They are the only known living animals that have a skull but no vertebral column. Along with lampreys, hagfish are jawless and are living fossils; they are basal to vertebrates, and living hagfish remain similar to ...
any of about 30 species of marine vertebrates placed with the lampreys in the class Agnatha. Hagfishes are divided into two families: Myxinidae, ... [6 related articles]
Hag'fish` (- fĭsh`), noun (Zoology) See Hag , 4. 
[n] - eellike cyclostome having a tongue with horny teeth in a round mouth surrounded by eight tentacles
hag noun eellike cyclostome having a tongue with horny teeth in a round mouth surrounded by eight tentacles; feeds on dead or trapped fishes by boring into their bodies