Habitat: Generally inhabit reef tops and seaward reef slope. Most common between 20-80 feet. Polyps are extended only at night, their tentacles forming long meandering rows along the ridges. Distribution: Caribbean Characteristics: Colonies generally form large rounded domes, but also encrust, constructing large rounded plates. Surface covered with a convoluted system of ridges and valleys. A thin, but distinct groove runs along the ridgetops. Typically the ridges are brown and valleys green, ten or whitish.