Imperium naturæ C. Linnaeus, 1758 - nature Mundus Plinius - physical world naturalia - natural bodies Regnum Animale C. Linnaeus, 1758 - animal kingdom see Kingdom Animalia Linnaeus, 1758 Class Pisces Linnaeus, 1758 see Superclass Pisces Linnaeus, 1758 Order Apodes Linnaeus, 1758 see Order Anguilliformes Rafinesque, 1810 Genus Xiphias Linnaeus, 1758 Xiphias gladius Linnaeus, 1758 - swordfish