Central Taxonomic Thesaurus

Taxon Search
  Animalia
      Mollusca
            Cephalopoda
                    Ammonoidea
                          Turrilitaceae
                            Nostoceratidae
                                     Bostrychoceras
                                     Didymoceras
                                             Didymoceras stevensoni
                                             Didymoceras tricostatus
                                                   [Ancyloceras tricostatus]
                                     Exiteloceras
                                             Exiteloceras jenneyi
                                                   [Ancyloceras jenneyi]
                                     Helicoceras
                                     Nostoceras