|Note||Hydroid stolonal or sessile, hydranths with an oral whorl of capitate tentacles, with or without aboral filiform tentacles; medusa buds borne singly on hydranth body immediately above filiform tentacles or in similar position when these are absent.|
Medusa adapted to a crawling and walking mode of life, exceptionally still able to swim; without brood-chamber above manubrium; with or without continuous or interrupted nematocyst ring along margin; gonads around manubrium or developed on manubrial protrusions; with six to eleven radial canals, some bifurcating shortly distal to manubrium; mouth circular with or without nematocyst knobs; with up to 60 marginal tentacles, dichotomous, upper branch with several nematocyst clusters, lower with adhesive organ; often asexual reproduction by medusa budding or by fission; with abaxial ocelli at tentacle base.
|Source||Schuchert, P. (2006). The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 1. Revue suisse de Zoologie. 113: 325-410. available online at http://www.biodiversitylibrary.org/item/128494#page/101/mode/1up|