Figure 1

Examples of opisthobranch species. A Micromelo undata (Bruguière, 1792) (Acteonoidea) – Queensland, Australia, B Scaphander lignarius (Linné, 1758) (Cephalaspidea) – Northern Sea, C Chelidonura pallida Risbec, 1951 (Cephalaspidea) – Queensland, Australia, D Elysiella pusilla Bergh, 1872 (Sacoglossa) from the Indo Pacific, feeding on the green alga Halimeda; due to incorporation of chloroplasts, Elysiella has the same colour as the algae, E Aplysia punctata (Cuvier, 1803) (Anaspidea) – Mediterranean Sea, F Tylodina perversa (Gmelin, 1791) (Tylodinoidea) – Mediterranean Sea, G Pleurobranchaea meckelii Meckel in Leue, 1813 Mediterranean Sea.