obelia

From Ancient Greek ὀβελία (obelía, “a round cake”).

obelia (plural obelias)

1. (zoology) Any of various colonial marine hydroids of the genus Obelia.
   • 1970, Marie M. Jenkins, Animals Without Parents, page 55,

     All the polyps and branches of obelias are supported and protected by a thin, transparent, horny covering which is made by the outer layer of cells. About each polyp the horny covering is in the shape of a goblet or cup.

   • 1975, Jacques Cousteau, The Ocean World of Jacques Cousteau: The Act of Life, page 42,

     Fragile but menacing, obelias are colonies ranging from one to eight inches in length which grow on seaweeds, rocks, and piles. The medusa, only one stage in the obelia’s life cycle, has anywhere from eight to 24 tentacles, […] .

   • 1999, Martin Walters, Jinny Johnson, The World of Animals, 2011, page 31,

     […] some [hydroids], like obelias, live in stalked colonies […] .