Well, what can you say!  Don't these look just like the surface of a human brain? To the right is the Smooth Brain Coral, Diploria strigosa and on the left  is the Grooved Brain Coral, Diploria labrynthiformis.  You can tell them apart by the extra valley inside the ridges.  These are the most common corals in Bermuda and you can find them anywhere you go.  The polyps only come out at night and it is difficult to distinguish individual polyps as they seem to merge together because they are so densely spaced.   These colonies can reach several meters in diameter although growing at 5mm per year, a colony that size is quite old and likely to have sustained some damage due to disease, predation or storm activity.  Here two colonies have grown together and are competing with each other for space to continue to expand.