Hard white substance and likely Vermetid snails?

[W Haymaker]

The white substance is somewhat hard. Came in on a clam and spread a bit but has since stopped or slowed dramatically.

The other appears to be Vermetid snails? I have a couple at the base of a few frags.

 

[OrionN]

1st picture is that of the shell of tiny feather duster.
You are correct, the 2nd picture is that of a shell of a Vermetid snail.

 

[KJ]

1pic Spirorbid worms.
2pic Vermetid snail.

 

[kirstyflash]

1pic Spirorbid worms.
2pic Vermetid snail.

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