Chondropoma montanum C. de la Torre & P. Bartsch,1938
Parachondria mordax (C.B. Adams, 1849)
Abbottella moreletiana (J.C.H. Crosse, 1873)
Abbottella moreletiana gabriella P. Bartsch, 1946
Opisthosiphon moreletianum (S.A.A. Petit De La Saussaye, 1842)
Annularia morenoi (C. de la Torre& P. Bartsch, 1941)
Adamsiella moribunda (C.B. Adams, 1849)
Tropidophora morondavensis E. Fischer-Piette, 1949
Chondrothyrium mortiarum M.I. Sánchez Roig, 1951
Tropidophora moulinsii (J.P.S. Grateloup, 1832)
Annularia moussoniana C.B. Adams, 1851
Parachondria muchai Watters, 2016
Dissostoma mumia (FOSSIL) (J.B.P.A. Lamarck,1804 †)
Tudora muskusi H.B. Baker, 1924
Tudora muskusi grandiensis H.B. Baker, 1924
Parachondria mutica (C.B. Adams, 1849)
Bermudezia najazaensis (C. de la Torre& P. Bartsch, 1941)
Chondrothyra natensoni C. de la Torre & P. Bartsch,1938
Ramsdenia natensoni (C. de la Torre& P. Bartsch, 1941)
Otopoma naticoides (C.A. Récluz, 1843)
Georgia naticopsis (J.R. Bourguignat, 1882)
Chondropoma navassense G.W. Tryon, 1866
Chondropoma neglectum (J. Gundlachin L. Pfeiffer, 1856)
Colobostylus negrilensis (C.B. Adams, 1845)
Colobostylus nelsoni W.F. Clapp, 1914
Abbottella newcombi (J.C.H. Crosse, 1873)
Chondropoma newcombianum (C.B. Adams)
Chondropoma nicolasi C. de la Torre & P. Bartsch,1938
Chondropoma nigriculum (J. Gundlach, 1860)
Abbottella nitens G.T. Watters, 2013
Lithidion niveum S.A.A. Petit De La Saussaye,1850
Clydonopoma nobilis (L. Pfeiffer, 1852)
Ramsdenia nobilitata (J. Gundlach in F. Poey,1858)
Rhytidopoma nodulatum (F. Poey, 1851)
Ramsdenia notata (C. de la Torre& P. Bartsch, 1941)