Alcadia macilenta (C.B. Adams, 1849)
Pleuropoma macleayi (J.W. Brazier, 1876)
Alcadia macmurrayi (L. Pfeiffer, 1867)
Gemma magna (FOSSIL) (W.H. Dall, 1903 †)
Alcadia major (J.E. Gray, 1824)
Alcadia mammata (P.F. Röding, 1798)
Helicina marchionissa J.B. Hombron& C.H. Jacquinot, 1848
Sulfurina martensi (A. Issel, 1874)
Geotrochatella martensis (P.V. Gredler, 1884)
Calybium massiei L.J. Morlet, 1891
Orobophana maugeriae (J.E. Gray, 1824)
Alcadia maxima (G.B. Sowerby, 1842)
Emoda mayarina (F. Poey, 1854)
Emoda mayarina mirandensis (C.G. Aguayo & M.L. Jaume,1954)
Sturanya mediana (Gassies, 1870)
Alcadia megastoma (C.B. Adams, 1849)
Orobophana meineckei M.C. Neal, 1934
Eutrochatella mendozana H.A. Pilsbry, 1928
Helicina menkeana R.A. Philippi, 1847
Gemma merdigera (L. Pfeiffer, 1855)
Troschelviana mestrei (R. Arango, 1879)
Ogasawarana metamorpha H. Minato, 1980
Fadyenia metcalfeiana E. Chitty, 1857
Troschelviana methfesseli (L. Pfeiffer, 1862)
Sulfurina micholitzi (A.J. Wagner, 1905)
Pyrgodomus microdinus (P.M.A. Morelet, 1851)
Alcadia microstoma (C.B. Adams, 1850)
Poenia midyetti H.G. Richards, 1938
Ogasawarana minamijimana T. Habe, 1973
Helicina miniata R.P. Lesson, 1831
Alcadia minima (A.V.M.D. D'Orbigny,1842)
Ceratodiscus minimus (J. Gundlachin L. Pfeiffer, 1859)
Necaxia minuscula (L. Pfeiffer, 1859)
Schasicheila misantlensis P.H. Fischer& J.C.H. Crosse, 1893
Gemma mohriana (L. Pfeiffer, 1861)