obelia

noun

Any of various marine hydroids of the genus Obelia that exist chiefly as colonies of polyps growing in a branchlike form on surfaces such as piers or rocks.

noun

A genus of campanularian polyps, distinguished from Campanularia by the flat discoidal medusæ with many marginal tentacles and eight interradial vesicles.

noun

Any of various colonial marine hydroids of the genus Obelia.