Imperium naturae C. Linnaeus, 1758 - nature Regnum Animale C. Linnaeus, 1758 - animal kingdom see Kingdom Animalia Linnaeus, 1758 Class Mammalia Linnaeus, 1758 - mammals Ungulata Linnaeus, 1766 Order Belluae Linnaeus, 1758 Genus Hippopotamus Linnaeus, 1758 - hippopotamus