New species of Neritidae (Neritimorpha) from the Ypresian and Bartonian of the Paris and Basse-Loire Basins, France Author Symonds, Malcolm Francis Author Pacaud, Jean-Michel text Zootaxa 2010 2606 55 68 journal article 10.5281/zenodo.197721 7fbbbf17-731f-4905-a25b-cea2c544bf38 1175-5326 197721 Genus Clithon Montfort, 1810 Type species. By original designation: Nerita corona Linné, 1758 . Recent, fresh to brackish water, eastern Indian Ocean to the southwestern Pacific. Diagnosis . Small spire, large body whorl, some species with one subsutural row of spines, labial area smooth with one or more teeth on margin, operculum smooth or bearing minute granules on exterior surface, inner side with two apophyses connected by calcareous callus.