This second revised edition includes 35 species not included in the first edition, including 13 nudibranchs. Information on each species has been updated from the first edition. This full colour guide describes 285 species of inshore, subtidal marine invertebrates that are commonly observed by biologists, divers and naturalists from the Gulf of Alaska to central Baja California. Each species is illustrated with a colour photo and provides a narrative which includes habitat, identification, depth and geographic range and size.