Dictionary of Ichthyology
cyclospondylous = a type of vertebra consisting of calcified rings around the notochord in Elasmobranchii and Holocephali. The calcification extends only to the chordacentrum or notochordal sheath, the arches are cartilaginous.
asterospondylous = a type of vertebra with radiating, star-like calcifications extending to the chordacentrum and autocentrum, e.g. in some Elasmobranchii.