The hagfishes comprise a uniform group of some 60 species inhabiting the cool or deep parts of the oceans of both hemispheres. They are considered the most primitive representatives of the group of craniate chordates, which - apart from the hagfishes that show no traces of verte brae -includes all vertebrate animals. Consequently the hagfishes have played and still playa central role in discussions concerning the evolution of the vertebrates. Although most of the focus on hagfishes may be the result of their being primitive, it should not be forgotten that, at the same time, they are...