Pectina coral. Have never owned it, but looked at a piece a long time ago in a reputable LFS. If I am remembering correctly, it's kind of like an abberation as far as stony corals are concerned. It doesn't really have the polyps that you are used to seeing in Acroporas, it is more of like a membrane covering the body. It can be easily damaged, and it is otherwise pretty much the same as other stony corals, not the most difficult species to keep. Of course, this is coming from a faded memory from around 5 or so years back, the only thing I can say for sure is that it is Pectina.
Although, on a second look, those look like ridges in the coral itself, which leads me to believe it is a Hydnophora (spelling?) coral, which I have never been successful in keeping. Not sure if that's because it's a difficult to keep species, the ones I've gotten have been damaged in the store, or if I just wasn't doing things right with it. Look for ridges in the coral and a rougher appearance to the flesh. It also often has it's polyps extended and has a hairy appearance.
It should be easy to tell the difference between Pectina sp. and Hydnophora sp. based on the texture of the coral.