What is this Coral?

[marie]

I believe Siderastea has larger calices (between 2-4mm) and have tentacles not an actual extended polyp like porites.
Porites has a smaller calice (1-1.5mm in diameter) and polyps that are similer to montiporas.
To me the photos don't look anything like a porites but then again I'm not a coral taxonomist....and I didn't stay in a holiday express inn last night

*edit* siderastrea also appears to be a very common coral in the atlantic, not so much in the pacific which would explain why some of us aren't very familiar with it