Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Polyplacophora Blainville, 1816 [monotypic] - chitons
     Subclass Polyplacophora Gray, 1821 [monotypic] see Class Polyplacophora Blainville, 1816
       Order Lepidopleurida Thiele, 1910
         Suborder Chitonina Thiele, 1909
           Family Ischnochitonidae Dall, 1889
             Subfamily Lepidochitoninae Iredale, 1914
               Genus Tonicella Carpenter, 1873
                 1 Subgenus Tonicina Thiele, 1906 see Genus Tonicina Thiele, 1906