A quantitative study of the decapod crustacean community commensal with the coral Pocillopora meandrina var. nobilis Verrill was undertaken and was accomplished through an analysis of communities collected in coral heads in Kaneohe Bay, Oahu. The coral head microhabitat was described and analyzed. The community was described and its relationship to the coral head habitat defined. It was found that community composition was affected by coral head size and that relative composition of the communities changed as the coral heads increased in size. Through stomach contents analysis and trophic behavior experiments the commensals were found to utilize the coral as a source of food, primarily by feeding on material caught on the coral. A correlation between the total biomass of the crustacean community and the surface area of the coral heads in which they were collected was found, suggesting that the com- munity is limited by the amount of surface area of a coralhead This may reflect the amount of food available to the symbionts. There was no good correlation between surface area of the corals and the biomass of the individual components of the community, indicating that other factors, such as the behavioral peculiarity of pairing and interspecific competition probably determine the exact composition of the community that a coral head can support. It was concluded that the crustaceans studied were true commensals with the coral, and that the commensal association involves the host providing a source of food as well as protection for the symbionts. / Typescript. Bibliography: leaves 62-64.