New polyp growth and old polyp death, but the bones remain in the group. Soft corals, horny corals and Blue Coral beads group life. Each polyp groups each with eight tentacles, stomach loop cavity 8 diaphragm, the six diaphragm cilia to flow into the stomach circular cavity, two diaphragm cilia for water leads to gastric circulation cavity. Bone within the bone. Soft corals are widely distributed, and the bones are separated from each other by the calcium spicules. Some types of disc shaped finger projections. Horny coral in tropical shallow water abundance, shape ribbon or branched, up to 3 meters in length, horny corals including the so-called the coral (red coral, rose coral), can be used as jewelry. The common types of Mediterranean red coral. Blue coral found in the Indian Ocean and the Pacific stony coral reefs formed, to form a block of up to 2 meters in diameter. Stony corals is the best known, most widely distributed species, monomer or group life. With black coral and thorn coral, the diaphragm 6 or 6, a simple pinnate tentacles. Stony corals, black coral and thorn coral and anemones be related difference is that the exoskeleton.