STAUROMEDUSAE UK

An online guide to the Stalked jellyfish (Stauromedusae) found
around the coastal waters of the United Kingdom and Ireland.
Includes notes on their identification, and where and how to find them.

A singular member of the group has the form of a jelly-fish, but does not act as one. This was formerly named Lucernaria, but is know known as Haliclystus octoradiatus. It was thought to swim like a jelly-fish, but it really creeps. Its form is like a ladies' sunshade that, instead of being the ordinary umbrella shape, tapers off to the stick at the top. What would be the ferrule of the sunshade is the footstalk of Haliclystus. By this footstalk it attaches itself to a weed, say, and hangs down its eight arms with their connecting web, and by means of a little knob on the edge of the web alternating with its "arms", it is able to take hold until it has "looped" like a geometer caterpillar, by bringing its footstalk forward and taking fresh hold. The extremeties of the eight arms (or ribs of the sunshade) are ornamented with tassles of tentacles, and it uses these after the manner of a sea anemone when it wishes to secure food. It, in fact, has some of the peculuarities of both jelly-fish and anemone, though it will not act quite consistently with either character. I have found it on Laminaria and other weeds at low water, and a few months since I picked one off the plumage of a dead guillemot, that had been drowned in a storm and afterwards washed ashore.

Ref:
By the Deep Sea -
A Popular Introduction to the
Wild Life of the British Shores
by Edward Step F.L.S.. 1896. Page 44-5.