What is this?

[mtis2000]

Picture taken in summer, south coast of UK, 5m deep on a rock, 1" long

sorry for poor picture quality!

 

[Diver Dennis]

I think it is a type of flatworm.

 

[mtis2000]

looking at it, it could only be a worm or a nudibranch but the picture is not good enough to spot any gills or other characteristic features except the greenish "spots". I browsed through many "slugs" web sites but I am completely ignorant of basic marine biology. We need a web site that concentrate on visible features rather than latin names!

 

[mtis2000]

according to an answer on another (french) forum, it would be an anemone curled on itself.
question remains.... which one? latin name or general one would help.

 

[LeslieH]

It certainly looks like a flatworm that has eaten something - that's why the midsection is bulging. Many of them are mollusc-eaters and have one of two types of feeding modes. The first is to slip into the shell of the mollusc and slurp up the inhabitant. Oyster & clam specialists use that method. The other is to swallow the entire thing, digest away, then spit out the empty shell.

 

[justleesa]

They can do that? WOW!! Thanks for the info Leslie!

 

[mtis2000]

I really do appreciate your input leslie (and I secretly hope you are right) but the anemone option does not seem so stupid if you imagine the critter from another angle (center of the animal...mouth..?...opening? when it "deploys" itself...?
what do you think?

 

[mtis2000]

I think after 36 hours of searching, it has to be a Strawberry Anemone (Actinia fragacea)
I wished Leslie were right cause I love worms and nudis!

 

[Papa_Bear]

Not a very good angle, and not much of a description, but it might be a Cowrie with its mantel over its shell? Did it move? Was it attached? did you probe it to see if it retraced? There is an Anemone that looks like this but it is usually flat on the surface it is attached to!

 

[LeslieH]

mtis -- I think your french forum friend was right. Here's a page on Actinia fragacea with images that look very similar to yours.
http://www.asturnatura.com/especie/actinia-fragacea.html

what a pity, worms have so much more class than anemones!