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 Glires Linnaeus, 1758 see Superorder Glires Linnaeus, 1758
               Genus Sciurus Linnaeus, 1758 - tree squirrels
                 Sciurus niger Linnaeus, 1758 - eastern fox squirrel