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 Feræ Linnaeus, 1758 see Grandorder Ferae Linnaeus, 1758
               Genus Phoca Linnaeus, 1758 - harbor, ringed, harp, and ribbon seals
                 1 Phoca Urſina Linnaeus, 1758 see Callorhinus ursinus (Linnaeus, 1758)
                 2 Phoca Leonina Linnaeus, 1758 see Mirounga leonina (Linnaeus, 1758)
                 3 Phoca Rosmarus Linnaeus, 1758 see Odobenus rosmarus (Linnaeus, 1758)
                 4 Phoca Vitulina Linnaeus, 1758 - harbor seal