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 Gasterosteus Linnaeus, 1758 - stickleback Gasterosteus ductor Linnaeus, 1758 see Naucrates ductor (C. Linnaeus, 1758)