If you can't already tell, Diploria labyrinthiformis, or grooved brain coral are named after their "brainy" appearance.  A majority of them look a lot like a human brain that we've seen on TV in the Frankenstein movies, or perhaps you've seen one in real life.  Diploria labyrinthiformis is considered a "hard coral" as most brain elkhorn corals are.  Some examples of soft corals are gorgonians, sea whips, and sea fans.  This is a picture of the Maze Brain Coral!

Maze Brain Coral Clearer Pic                                                     

Other species of brain coral can come in all colors and sizes. Here are a few images that you can check out!                 Pink Brain Coral       Green Brain Coral      Yellow Brain Coral          Open Brain Coral

    The small polyps that colonize and make up brain coral excrete a calcium carbonate outer layer which forms the skeletons of these creatures.  These polyp skeletons are often referred to as "valleys" from their large sizes and deep grooves.  “Brain coral skeletons snake around the coral head in shapes of jelly beans, half moons and squiggles” said Shedd The World's Aquarium.  They also talked about how the outside of these polyps in the brain coral contain these mesentary filaments “…which extend from the skin and secrete juices that digest any animals near the brain coral”.

Used with permission

photos from flickr by: jillhudgins, jayhem, DaseinDesign, mjar81

    The polyps have these mesentary filaments for a number of reasons.  In this case it's mostly for protection against other corals that have a faster growth rate than the brain coral.  Since brain coral grow as an impossibly slow rate, they are at risk from these faster growing corals that may outgrow them and block out their sunlight needed for the zooxanthellae to make food.