Live rock hitchhiker needs an ID please!

[johnd4g]

Today I discovered a new hitchhiker that came with my Liverocks.com rock. It is located in a hole in one of the rocks and looks like it has grown too large to come out. The openning to the hole is about half an inch wide but the hole itself looks like it gets larger in the rock. This hitchhiker looks like a small scallop but appears to have a soft shell, not a typical hard shell like you would expect a scallop or snail to have. It has short hairy looking tentacles along its openning. It opens and closes its "shell" like a scallop or clam would. It is white with a pinkish color to the hairy tentacles. Its about .75 inch wide and can open its "shells" about .25 inch wide.

Any ideas what this little guy is???
Thanks!

 

[Brad]

I would say that it is a scallop and that it's shell is likely harder than you think.