All coral polyps share two basic structural features with other members of their phylum. The first is a gastrovascular cavity that opens at only one end. At the opening to this cavity, commonly called the mouth, food is consumed and some waste products are expelled. A second feature all corals possess is a circle of tentacles, extensions of the body wall that surround the mouth. Tentacles help the coral to capture and ingest plankton for food, clear away debris from the mouth, and act as the animal’s primary means of defense (
Barnes, R.D., 1987;
Levinton, 1995).While coral polyps have structurally simple body plans, they possess several distinctive cellular structures. One of these is called a cnidocyte—a type of cell unique to, and characteristic of, all cnidarians. Found throughout the tentacles and epidermis, cnidocytes contain organelles called cnidae, which include nematocysts, a type of stinging cell. Because nematocytes are capable of delivering powerful, often lethal toxins, they are essential to capturing prey, and facilitate coralline agonistic interactions (
Barnes, R.D., 1987).