Gastropoda Cuvier, 1795 see Class Gastropoda Cuvier, 1795 Sacoglossa Ihering, 1876 see Order Sacoglossa Ihering, 1876 Plakobranchoidea Gray, 1840 Family Plakobranchidae Gray, 1840 Genus Elysia Risso, 1818 1 Elysia viridis (Montagu, 1804)