TUNICATA n.
A grand division of the animal kingdom, intermediate, in some respects, between the invertebrates and vertebrates, and by some writers united with the latter. They were formerly classed with acephalous mollusks. The body is usually covered with a firm external tunic, consisting in part of cellulose, and having two open…
VERTEBRATA n.
One of the grand divisions of the animal kingdom, comprising all animals that have a backbone composed of bony or cartilaginous vertebræ, together with Amphioxus in which the backbone is represented by a simple undivided notochord. The Vertebrata always have a dorsal, or neural, cavity above the notochord or backbone,…