Zeidora neritica J. Espinosa, J.A. Ortea& R. Fernández-Garcés, 2005
Zeidora nesta (H.A. Pilsbry, 1890)
Hemitoma neuvillei (FOSSIL) A.E.M. Cossmann& M.A. Peyrot, 190? †
Fissurella nigra R.P. Lesson, 1831
Amblychilepas nigrita (Sowerby, 1835)
Fissurella nigrocincta P.P. Carpenter, 1856
Emarginula nigromaculata (K.H.J. Thiele, 1930)
Fissurella nimbosa (C. Linnaeus, 1758)
Puncturella noachina (C. Linnaeus, 1771)
Puncturella nobilis (A. Adams, 1860)
Fissurella nodosa (I. von Born, 1778)
Emarginula nordica I. Pérez Farfante, 1947
Clypidina notata (C. Linnaeus, 1758)
Fissurella nubecula (C. Linnaeus, 1758)
Diodora nucula (FOSSIL) W.H. Dall, 1892 †
Cranopsis nymphalis L.R.L. Simone & C.M. Cunha,2014
Emarginula nystiana (FOSSIL) (J.A.H. Bosquet, 1851 †)
Tugali oblonga (W.H. Pease, 1861)
Amblychilepas oblonga (K.T. Menke, 1843)
Emarginula obovata A. Adams, 1852
Fissurella obscura G.B. I Sowerby, 1834
Diodora occidua B.C. Cotton, 1930
Diodora octagona (L.A. Reeve, 1850)
Diodora octagona reevei (M.M. Schepman, 1908)
Emarginula octaviana G.S. Coen, 1939
Hemitoma octoradiata (J.F. Gmelin, 1791)
Emarginella okinawaensis T. Habe, 1953
Montfortista oldhamiana (G. Nevill, 1869)
Scutus olunguis T. Iredale, 1940
Amblychilepas omicron (J.C.H. Crosse, 1864)
Buchanania onchidioides R.P. Lesson, 1831
Cornisepta onychoides (D.G. Herbert& R.N. Kilburn, 1986)
Emarginula oppressa K.H. Barnard, 1963
Tugali opuraensis (FOSSIL) J.A. Bartrum & Powell,1928 †
Fissurella oriens G.B. I Sowerby, 1834