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I too think it is L. clavigera which has long, yellow or orange tipped outgrowths all around the edge of the mantle.
(You might like to have a look at this site too.
Edit 10.10.13 Andy's site is no longer available on-line.
...but yes, hardly any doubt. See mine http://www.ispotnature.org/node/374092
THREE MARINE PROJECTS
Perhaps I place a few too many hyperlinks in my posts. Sooner or later many will fail. But it's a great pity that Andy Cowley's site has gone.
Andy was a prolific poster and contributor to marine fauna sites. He is well represented in EOL, Wiki and many others where I dwell for assurance and expertise.
As a British Marine Invertebrate Curator for EOL, Andy has 11 impressive 'collections' here http://eol.org/users/45221/collections
Mariners will be pleased to know that Andy Cowley's Shore website is now restored to the internet. It is a pleasure to host it for my friend and colleague.
Yes, that's nice - I've used it a lot(during a test period) for reassurance.
That looks like a great site, thaks JoC. I've always looked on Andy as the most reliable marine Ispotter, & posting Andrewcowley in the searchbox reaffirmed it.
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