Cnidarian, or, Coelenterate, an animal of the phylum Cnidaria, or Coelenterata. The phylum includes the corals, hydras, jellyfish, Portuguese man-of-war, and sea anemones. Cnidarians are water-dwelling animals. The body is typically cylindrical or bell-shaped and has a single opening used for taking in food and excreting wastes. Arranged around the opening are tentacles armed with cnidocytes, cells used to sting prey and enemies. Some cnidarians live singly, others in large colonies.The cnidarian has tentacles armed with cnidocytes, cells used to sting prey and enemies.
Crustacean is a member of a large class of animals with segmented bodies. Crustaceans belong to the same major division, or phylum, of the animal kingdom as insects and spiders.
Oceans cover most of the Earth's surface. They include a vast diversity of life, everything from plants to large mammals. Oceans represent a truly undiscovered world for most people. Take this quiz and learn more about ocean life.