Gastropoda
      Heterobranchia
            Opisthobranchia
                  Sacoglossa
                              Elysioidea
                                    Caliphyllidae
                                    Elysiidae
                                    Stiligeridae
                              Julioidea
                                    Juliidae
                              Oxynooidea
                                    Oxynoidae
                                    Volvatellidae
                              Placobranchoidea
                                    Placobranchidae