Contents: 1. Introduction. 2. Study areas. 3. Material and methods. 4. Results. 5. Discussion. 6. Acknowledgements. 7. References. From the introduction: Corals are mostly sessile animals belonging to the phylum Cnidaria under the class Anthozoa. The formation of colonial structure by the corals during the course of development is known as coral reefs. Corals are known to represent simple structural plan of anatomony with an opening i.e. mouth while the individual animal is termed as polyp. Mouth of the each polyp is bounded by tentacles which harbor the stinging cells i.e. nematocysts. The nematocysts help the corals for capturing is prey from oceanic waters. The namatocysts also worked as defence organs for the cnidarians. Corals usually capture plankton by its tentacles. Depostion of plankton is taken place inside the mouth while the food material is digested inside the cavity during its movement and absorption of the nutrient is take place thereafter. During the process of development, older polyps used to die and those are replaced by the formation of new polyps. After the death process, old structural architecture of coral used to work as reef and provide space for the formation of new corals.