1. Coelenterates are further divided into three main classes namely; Class Hydrozoa, Class Scyphozoa, and Class Anthozoa

2. The phylum Cnidaria contains about 10,000 described species divided into four classes: Anthozoa, Scyphozoa, Cubozoa, and Hydrozoa

3. The reef-framework consists of various biocoenoses (high growing corals, low growing corals, calcisponges, hydrozoa and bryozoa, solenoporacean algae).

4. The Hydrozoa may be defined, therefore, as Cnidaria in which two types of individual, the polyp and the medusa, may be present, each type developed …