There are two species in Bermuda, M. mirabilis seen here and M. decactis which has stubby, more club-like branches of the colony.  The polyps are small, about 2 mm, and they are open and feeding during the day in contrast to many corals which open only at night.  This genus is mostly found in the inshore waters rather than on the outer reefs and it prefers vertical surfaces rather than directly sitting on top of  the reef.