Cotton like growth on clam shell near mantle?

[PENNYWISE]

My crocea clam has a cottony growth growing on the shell near the top? What is this thing and will it hurt the clam? I can't post a picture because I'm bandwith challenged.

 

[jedininja]

It could be a couple things, Sponge, snail eggs, tuncates. Whatever it is, if its touching the mantle, I would remove it.

 

[PENNYWISE]

I thought maybe it was a sponge. I pulled most of it off. I'll keep an eye on it, thanks.