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 Mammalia Linnaeus, 1758 - mammals
           Quadrupedia Linnaeus, 1758 see Class Mammalia Linnaeus, 1758
             Order Belluæ Linnaeus, 1758
               34 Genus Eqvus Linnaeus, 1758 see Genus Equus Linnaeus, 1758
               35 Genus Hippopotamus Linnaeus, 1758 - hippopotamus