Echinothurioida

Echinothurioida

[‚ek·ə·nō·thu̇·rē′ȯid·ə]
(invertebrate zoology)
An order of echinoderms in the superorder Diadematacea with solid or hollow primary radioles, diademoid ambulacral plates, noncrenulate tubercles, and the anus within the apical system.