This relatively large hydroid, Corymorpha nutans, has no common name. And it is not common but occurs sporadically around the UK, appearing suddenly in fair numbers in one location from which it has apparently been absent for some years. Standing about 7cms from the bottom, it has a quite thick, fleshy stem and uses its delicate tentacles to catch minute items from the plankton. It is usually found in sandy or gravel sediments.
St. Abbs Marine Reserve, North Sea