posted by Anonymous .
One kind of fish, the hagfish, is considered an invertebrate by scientists. Why is this fish an invertebrate whereas all other fish are vertebrates?
- Biology - Reed
The Myxini are unique among living chordates in that they have a partial cranium (skull), but no vertebrae, and so they are not truly vertebrates. The skeleton is composed of cartilage, and lacks bone.
As a note on the question, the classification of Hagfish as invertebrate is under dispute, and far from agreed on. I am surprised your instructor moved you into this area of dispute.