ID Turbo snail hitch hiker(s)

[Palmer]

Hi there

Have a large turbo snail in my main display. Noticed what looks like two little Astraea looking snails fixed to a white scallop shell on the big turbo shell. From underneath the scallop shell a tube mouth comes out with pincers and it has two typical snail antenna. When I tried to knock it off it would not easily come off so I left it. The best pics I could take are below. I quickly searched on google and saw a thread on another site explaining and showing something similar but no positive ID. Thoughts?

http://www.ultimatereef.net/forums/s...=239554&page=2










Thoughts?