Helicoplacoidea

Helicoplacoidea

[‚hel·ə·kō·plə′kȯid·ē·ə]
(paleontology)
A class of free-living, spindle- or pear-shaped, plated echinozoans known only from the Lower Cambrian of California.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.