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An interesting picture. It appears to be a living specimen adhering to glass - can you remember any details?
When and if removed from their normal home, even carefully, they usually die.
Am am here, in History, because I am research for my own post.
I've just been though the majority of Limpet posts Mike (and piggehwoo). You might notice that I have modified quite a few because, as you know, they are very hard to tell apart from shell pictures. This observation is quite unusual but you and I seem to be the only ones to have thought so.
I have read and read, talked to experts, posted a few and STILL believe it might be impossible to tell from the shells alone.
There are a good number of limpet Observations, http://www.ispotnature.org/node/646438 is one of mine. Despite me making it easy for people to agree, there are still none.
And here is my only slightly more educated post http://www.ispotnature.org/node/648659 in which I have written -
"It is very difficult to find definitive information which allows correct separation of the three most common ones and a huge overlap in descriptions of each. Book illustrations are somewhat vague and the internet is loaded with pictures which do nothing for separation."
Jan Light's "straightforward" Guide is here http://www.glaucus.org.uk/Limpets.htm She writes "With practice it is possible to discern these differences and make accurate judgements based on exterior appearance but it is not foolproof even for the ‘experts’" Oh dear then!
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