Sphaeractinoidea

Sphaeractinoidea

[sfir‚ak·tə′nȯid·ē·ə]
(paleontology)
An extinct group of fossil marine hydrozoans distinguished in part by the relative prominence of either vertical or horizontal trabeculae and by the presence of long, tabulate tubes called autotubes.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.