Chordate of the three subdivisions of chordates, all have distinct skulls. They include the hagfish, which have no vertebrae. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or possibly all deuterostomes, are by their tails". Most craniates are vertebrates, in which the notochord is replaced by the vertebral column. These consist of a series of bony or cartilaginous cylindrical vertebrae, generally with neural arches that protect the spinal cord, and with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, and are therefore not regarded as vertebrates, but as members of
Animals, Property, and the Law our views on animals, cruelty, what sort of pain is 'necessary,' what kind of a society allows defenseless creatures to be shot, burned, prodded, beaten, etc. His explanations are always thoughtful, his analyses penetrating, his examples interesting and entertaining." Antonia Layard of "Environmental Values" was more critical, as she felt that Francione experienced difficulty when he "attempts to put something in its place, for he does not describe how Regan's theory of animal rights might be implemented in practice, a contribution most lawyers would expect him to make. In particular, Francione cites Regan to submit that animals should not have