Nudibranchs, or sea slugs, are a group of marine gastropod molluscs whose adults lack shells, an evolutionary loss that has led to a wide variety of body shapes, colours and colour patterns, making them popular with divers and underwater photographers. In this book, experienced nudibranch experts Bernard Picton and Christine Morrow provide an accessible and authoritative photographic identification guide for anyone interested in finding and identifying nudibranchs in the coastal waters of Britain, Ireland and Northwest Europe. Covers 200 species, each on its own two-page spread. Includes in situ photos to aid finding nudibranchs under water and on the shore. Features photos of nudibranchs’ distinctive spawn coils and studio photos showing detailed anatomy. Presents key distinguishing features and essential information on size, habitat, diet and distribution