Studies on the biology and ecology of some Indo-Pacific Terebra from Eniwetok Atoll

Abstract

Some aspects of the biology and ecology of fourteen species of Indo-Pacific Terebra collected at Eniwetok Atoll have been studied. Terebra exhibit both external and internal sexual dimorphism. Mating was observed and described, and differences in the sex ratio and spawning season are discussed. Terebra are negatively photosensitive to white light, but are unaffected by low intensity red light. Endogenous rhythms of locomotory activity are exhibited by the species of Terebra studied. The functional anatomy of the terebrid digestive system is presented, and the feeding process is described. Differences are noted between T. maculata and T. crenulata in the nature of the prey, the time of feeding, and the percent of the population feeding each day. The shallow water sand community structure of Eniwetok Atoll is examined.