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.
Imagine trying to figure out the details of a jellyfish's life by studying the formless blob that it quickly becomes out of water. Find about about these creatures through jellyfish behavior.
Unless you've butchered an octopus, you might assume that it's as red-blooded as you are. And you'd be wrong. Why are octopuses the original blue bloods?