Cnidaria is a phylum containing over Cnidaria is a phylum containing over 10,000 species of animals found in aquatic and marine environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey.
Hydras are a minute freshwater coelenterate with a stalklike tubular body and a ring of tentacles around the mouth. It excretes out digestive waste by squirting. Squirting is a process in which hydra contracts longitudinally and throws out the waste from hypostome (anus and mouth).
Corals are invertebrate animals. Coral are generally classified as either "hard coral" or "soft coral". There are around 800 known species of hard coral. Corals urinary system works the same way as all cndarias do. The same hole to there stomach doubles as a anus.
Portugese Man-O-War is a floating colonial coelenterate with a number of polyps and a conspicuous float. It occurs chiefly in warm seas, and bears long tentacles that can inflict painful stings.They have no blood and they have no brain. They also have no nervous or respiratory system. They are made up of 95% water. There urinary system works as hypos tome does, Jellyfish excrete from their internal cavity. Some of them also use waste products to feed microorganisms, living in mutual symbiosis inside them, in change of nutrients.