Nineteen subtidal sampling stations, including 9 biological stations, were established in Coki Bay, St. Thomas, U.S. Virgin Islands. Sedimentary, chemical and faunal samples were taken at the biological stations. Data from the sedimentary and chemical analyses were used to characterize the Coki Bay subtidal habitat as a medium to high energy environment with regular (i. e. relatively stable) periodicity. This characterization was confirmed by 1. the comparison of species diversity values for harpacticoid copepods from the Coki Bay samples with diversity values for other similar samples in different habitats (Coull, 1968, 1972; Drzycimski, 1969), and 2. the demonstration of statistical relationsips by correlation, dependence, and affinity analyses between both physical and faunal variables. Correlation analysis was done by standard statistical techniques. Dependence relationships for physical, chemical and faunal data were analysed by comparing the standard errors of regression for each possible variable pair with a correlation coefficient greater than 0.5. An affinity index matrix was also determined for each possible variable pair. Affinity dendrograms were then constructed for both physical data and species composition for all stations.Data from the comparison of species diversity values led to the postulation of a tentative hierarchy of influences on species diversity;i.e. that habitat energy content has more influence on species diversity than either latitudinal difference or substratum type. These results are in accordance with the predictions of the stability-time hypothesis for this type of environment.