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 Thoracici Linnaeus, 1758 Genus Perca Linnaeus, 1758 Perca schraetser Linnaeus, 1758 see Gymnocephalus schraetser (C. Linnaeus, 1758)