Polygyra latispira H.A. Pilsbry, 1896
Praticolella lawae (J. Lewis, 1874)
Patera leatherwoodi W.L. Pratt, 1971
Ashmunella lenticula W.O. Gregg, 1953
Daedalochila leporina A.A. Gould, 1848
Ashmunella levettei (T.B. Bland, 1881)
Polygyra lingulata (G.P. Deshayesin A.E.J. Férussac, 1859)
Neohelix lioderma H.A. Pilsbry, 1902
Millerelix lithica (L.R. Hubricht, 1961)
Allogona lombardii M. Smith, 1943
Triodopsis loperi H.A. Pilsbry
Trilobopsis loricata (A.A. Gould, 1846)
Ashmunella macromphala J. Vagvolgyi, 1974
Inflectarius magazinensis (H.A. Pilsbry& J.H. Ferriss, 1907)
Stenotrema magnafumosum H.A. Pilsbry, 1900
Cryptomastix magnidentata H.A. Pilsbry, 1940
Neohelix major (A. Binney, 1837)
Triodopsis maratima H.A. Pilsbry, 1890
Vespericola marinensis B. Roth & W.B. Miller,1993
Eduardus martensiana (H.A. Pilsbry, 1907)
Linisia matermontana (H.A. Pilsbry, 1896)
Stenotrema maxillatum A.A. Gould, 1848
Ashmunella mearnsii (W.H. Dall, 1895)
Vespericola megasoma (H.A. Pilsbry, 1928)
Ashmunella mendax H.A. Pilsbry & J.H. Ferriss,1917
Ashmunella meridionalis H.A. Pilsbry, 1948
Triodopsis messana L.R. Hubricht, 1952
Ashmunella metamorphosa H.A. Pilsbry, 1905
Praticolella mexicana K.E. Perez, 2011
Ashmunella microdonta H.A. Pilsbry & J.H. Ferriss,1909
Ashmunella milesi D.M. Reeder, 1993
Mesodon mitchellianus H.C. Lea, 1839
Praticolella mobiliana (H.C. Lea, 1841)
Ashmunella mogollonensis H.A. Pilsbry, 1905
Stenotrema monodon T. Rackett, 1821