Note:  Do not rely on this information. It is very old.

Echinozoa

Echinozoa, a name given to a subdivision of the phyllum Echinodermata, and including the Echinoidea, Asteroidea, and Ophiuroidea (brittlestars), and sometimes the Holothuroidea. The last is, however, often separated as a distinct group under the name Scytodermata.