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 Elysia viridis (Montagu, 1804)