Sea anemone (Metridium) belongs to class Anthozoa of phylum Coelenterata. It inhabiting warm coastal wales along the North Atlantic and Pacific coasts. The characteristic feature of Coelenterata is presence of stinging cells or nematocysts. Protozoa may be defined as microscopic and unicellular animalcules without tissues and organs having one or more nuclei e.g., Amoeba, Podophyra, Leishmania. Porifera includes multicellular organisms with cellular level of body organization. Body with many pores (ostia) canals and chambers that serve for the flow of water. One or more water exits or oscula present. Echinoderms are exclusively marine and largely bottom dwellers enterocoelous coelomate, triploblastic animals. They have a peculiar water vascular system.