Webster’s Revised Unabridged Dictionary · 1913
Cystidea
Cys·tid′e·a (s?s-t?d′?-?), n. pl. [NL., fr. Gr. κύστις a bladder, pouch.] (Zoöl.) An order of Crinoidea, mostly fossils of the Paleozoic rocks. They were usually roundish or egg-shaped, and often unsymmetrical; some were sessile, others had short stems.