Helicina monarquiana (T. Rackett, 1821)
Helicina monteiberia H. Sarasúa, 1976
Gemma monteverdensis I. Richling, 2004
Palaeohelicina moquiniana (C.A. Récluz, 1851)
Fadyenia morchiana E. Chitty, 1857
Helicina moreletiana L. Pfeiffer, 1851
Fadyenia moricandiana (C.B. Adams, 1851)
Calybium mouhoti (L. Pfeiffer, 1862)
Fadyenia moussoniana E. Chitty, 1857
Sturanya multicolor (A.A. Gould, 1847)
Helicina munda F. Haas, 1951
Palaeohelicina muruensis (C. Hedley, 1891)
Emoda najazaensis C.G. Aguayo & M.L. Jaume,1954
Lucidella nana L. Pfeiffer, 1857
Alcadia neebiana (L. Pfeiffer, 1862)
Helicina nehoueensis W.D. Hartman, 1889
Helicina nemoralis R.J.L. Guppy, 1866
Helicina neritella J.B.P.A. Lamarck, 1801
Helicina neritella diplocheila A.J. Wagner, 1906
Idesa nesiotica W.H. Dall, 1892
Fadyenia newcombiana E. Chitty, 1857
Pleuropoma nicobarica (L. Pfeiffer)
Schasicheila nicoleti R.J. Shuttleworth, 1852
Pleuropoma niilauensis M.C. Neal, 1934
Alcadia nitida (L. Pfeiffer, 1839)
Ogasawarana nitida H. Minato, 1980
Alcadia nobilis (C.B. Adams)
Eutrochatella nobilis (C.B. Adams, 1850)
Eutrochatella nobilis retreatensis H.B. Baker, 1934
Geophorus nogieri (P. Dautzenberg& d'Hamonville, 1887)
Pleuropoma nonouensis M.C. Neal, 1934
Tristramia notata (L. Pfeiffer, 1856)
Alcadia novogranadensis B. Hausdorf, 2006
Alcadia nuda (R. Arango in L. Pfeiffer,1866)
Pleuropoma oahuensis H.A. Pilsbry & C.M. Cooke,1908