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
                 Subgenus Tonicina Thiele, 1906 see Genus Tonicina Thiele, 1906