Hagfish

Hagfish, common name for any of several eel-like, parasitic fishes that are the most primitive of the craniate chordates. Hagfishes, which attain a maximum length of almost 91 cm (almost 36 in), are boneless animals with a continuous fin extending from the upper to the lower body surface, a row of numerous mucous-producing pores along the body, poorly developed eyes, a single large nostril, and a circular mouth that lacks jaws and is surrounded by tentacles. The roof of the mouth contains a single tooth; the muscular tongue has two rows of strong, pointed, horny teeth that are periodically shed and re-formed. The hagfish attaches itself to the body of a fish by means of its mouth and short surrounding tentacles and files through the flesh with its rasping tongue. It can consume several times its own weight in a few hours. While attached to its prey, it breathes through about 5 to 15 external gill openings situated on each side of its body. Hagfish also act as scavengers, consuming the flesh of dead fish. The hagfish is found in all temperate seas. The best-known species is the bright-red Atlantic hagfish, about 38 cm (about 15 in) long, which is found in the North Atlantic Ocean.

Scientific classification: Hagfishes make up the family Myxinidae. The Atlantic hagfish is classified as Myxine glutinosa.

See also Lamprey.