The Hydrozoa are colony - forming species including the freshwater hydra. 4ouH hs befujeeo fe-nf-oes -fhr khs mACyy fix cynS dcuih. Jellyfish And Other Cnidarians The Phylum Cnidaria Coelenterata contains about 9000 species of hydras jellyfishes sea anemones corals etc. . Medusoid types are those like jellyfishthe body or bell is on top and tentacles and mouth hang down. Perhaps the best-known medusoid animals are the jellies jellyfish. Polyp or stalk and medusa or bell. Cnidarians Medusa Cylindrical body arm-like tentacles mouth opens upward usually sessile Polyp Medusa bell shaped bottom mouth is at the bottom free-swimming structure fringe of tentacles that hang from the edge of the bell mouth opening located under the bell a gastrovascular. The epidermis and the gastrodermis. Parazoa Eumetazoa diploblastic or Eumetazoa triploblastic 3 Body cavity if triploblastic. Medusa - bell-shaped and free swimming...