Grooved brain coral

This species of reef-building coral has a hemispherical, brain-like shape with a brown, yellow, or gray colour. It has characteristic deep, interconnected double-valleys. These polyp-bearing valleys are each separated by grooved ambulacral ridges. There may be a difference in colour between the valleys and the grooves. Diploria labyrinthiformis can grow upward at a rate of approximately 3.5 millimeters per year, achieving about 2 metres (6.6 feet) in diameter. During its planktonic larval stage, the coral has locomotion. After that time, it becomes permanently sessile. This species is a suspension feeder, and survives mainly on zooplankton and bacteria. These are captured by the polyps, by extruding mesenterial filaments and tentaces. The polyps have nematocysts which are triggered to hold their prey immobile. The prey is then transported to the mouth with the assistance of mucus and cilia. Diploria labyrinthiformis is hermaphroditic, and reproduces through brooding. This entails the egg being fertilized by the sperm within the polyp, followed by the release of the larvae.