What is this critter?

[bstorer]

I cant see any flesh, so this may be hard to identify. I circled and pointed out what I am talking about. Looks like it has some type of shell that will open and close. It is stationary and can't move. I don't think it is a clam, but I guess I could be wrong. Let me know what else you may need to identify this. Thanks.

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[Sniperhank]

It would be more likely to be a barnacle or something similar rather than a clam. It is hard to tell with it covered in coraline like that though.

[bstorer]

I dont think it is a barnacle bc nothing comes out from the area to filter feed. I had a barnacle and it looked as though a skeleton hand came out to catch food...lol. I figured it would be a hard one to id bc of the coraline, it's size, and you can't see any flesh under the shell or door.

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[coralbandit]

Some type of bivalve IMO?