A polyp lives with one end of its body attached to the sea bottom. The mouth and tentacles extend upward at the other end. Polyps may exist singly or may live together in colonies. Colonies are produced when polyps form buds that detach and become new polyps. Hydras and sea anemones are examples of single polyps, and hydroids and most corals are colony-forming polyps.
Some cnidarians have either medusa or polyp stages, or both, in their life cycles.
The medusas are produced from special polyp buds that eventually break free and swim away. Then the medusas produce eggs and sperm that unite and develop into polyps. How to cite this article.