Volume 25 of this authoritative review series continues the high standard set by the editors in the past. Marine biologists everywhere have come to value and enjoy the wide variety of thought-provoking papers written by invited experts.In this volume are reviews of four animal groups which span the entire range of the marine food chain. The role of parasites in ecology is a growing interest and the parasites of zooplankton are described in detail for the first time. Aspects of thegastropods, cephalopods and fish life are also examined in detail.