[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Mollusca Linnaeus, 1758 - molluscs
         Branch Eucephala
           Grade Echinoglossa
             I Class Gastropoda Cuvier, 1795 - snails and slugs
             II Class Cephalopoda Cuvier, 1795 - cephalopods
             III Class Scaphopoda Bronn, 1862 - tusk shells