Alcadia macilenta (C.B. Adams, 1849) Jamaica
Pleuropoma macleayi (J.W. Brazier, 1876) Australia, Palm Island
Alcadia macmurrayi (L. Pfeiffer, 1867)
Gemma magna (FOSSIL) (W.H. Dall, 1903 †) USA, Florida, Glades
Alcadia major (J.E. Gray, 1824) Cuba
Alcadia mammata (P.F. Röding, 1798)
Helicina marchionissa J.B. Hombron& C.H. Jacquinot, 1848 French Polinesia, Noukahiva
Sulfurina martensi (A. Issel, 1874) Malaysia, Borneo16 mm
Geotrochatella martensis (P.V. Gredler, 1884) Laos16,38 mm
Calybium massiei L.J. Morlet, 1891 Laos
Orobophana maugeriae (J.E. Gray, 1824) French Polynesia, Topatii11 mm
Alcadia maxima (G.B. Sowerby, 1842) Jamaica
Emoda mayarina (F. Poey, 1854) Cuba23 mm
Emoda mayarina mirandensis (C.G. Aguayo& M.L. Jaume, 1954) Cuba22 mm
Sturanya mediana (Gassies, 1870)
Alcadia megastoma (C.B. Adams, 1849) Jamaica
Orobophana meineckei M.C. Neal, 1934 Hawaii
Eutrochatella mendozana H.A. Pilsbry, 1928
Helicina menkeana R.A. Philippi, 1847
Gemma merdigera (L. Pfeiffer, 1855) Veracruz, Mexico
Troschelviana mestrei (R. Arango, 1879) Cuba
Ogasawarana metamorpha H. Minato, 1980 Japan, Ogasawara Islands
Fadyenia metcalfeiana E. Chitty, 1857 Jamaica
Troschelviana methfesseli (L. Pfeiffer, 1862) Cuba
Sulfurina micholitzi (A.J. Wagner, 1905)
Pyrgodomus microdinus (P.M.A. Morelet, 1851) Guatemala
Alcadia microstoma (C.B. Adams, 1850) Jamaica
Poenia midyetti H.G. Richards, 1938 Honduras, Roatan Island
Ogasawarana minamijimana T. Habe, 1973 Japan, Ogasawara Islands
Helicina miniata R.P. Lesson, 1831 French Polynesia, Bora-Bora
Alcadia minima (A.V.M.D. D'Orbigny,1842) Cuba6 mm
Ceratodiscus minimus (J. Gundlach in L. Pfeiffer, 1859) Cuba
Necaxia minuscula (L. Pfeiffer, 1859) Veracruz, Mexico
Schasicheila misantlensis P.H. Fischer& J.C.H. Crosse, 1893 Misantla, Mexico
Gemma mohriana (L. Pfeiffer, 1861) Veracruz, Mexico