Helicina monarquiana (T. Rackett, 1821) Solomon Islands14 mm
Helicina monteiberia H. Sarasúa, 1976 Cuba
Gemma monteverdensis I. Richling, 2004 Costa Rica6,6 mm
Palaeohelicina moquiniana (C.A. Récluz, 1851)
Fadyenia morchiana E. Chitty, 1857 Jamaica
Helicina moreletiana L. Pfeiffer, 1851
Fadyenia moricandiana (C.B. Adams, 1851) Jamaica
Calybium mouhoti (L. Pfeiffer, 1862) China, Guangxi province12 mm
Fadyenia moussoniana E. Chitty, 1857 Bahamas
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 Cuba
Lucidella nana L. Pfeiffer, 1857 Jamaica
Alcadia neebiana (L. Pfeiffer, 1862) Cuba
Helicina nehoueensis W.D. Hartman, 1889
Helicina nemoralis R.J.L. Guppy, 1866 Tobago
Helicina neritella J.B.P.A. Lamarck, 1801 Jamaica
Helicina neritella diplocheila A.J. Wagner, 1906 Jamaica9 mm
Idesa nesiotica W.H. Dall, 1892 Galapagos
Fadyenia newcombiana E. Chitty, 1857 Jamaica
Pleuropoma nicobarica (L. Pfeiffer) India, Cuddalore
Schasicheila nicoleti R.J. Shuttleworth, 1852 Veracruz, Mexico
Pleuropoma niilauensis M.C. Neal, 1934
Alcadia nitida (L. Pfeiffer, 1839) Cuba6,8 mm
Ogasawarana nitida H. Minato, 1980 Japan, Ogasawara Islands
Alcadia nobilis (C.B. Adams) Jamaica
Eutrochatella nobilis (C.B. Adams, 1850) Jamaica10,2 mm
Eutrochatella nobilis retreatensis H.B. Baker, 1934 Jamaica15,4 mm
Geophorus nogieri (P. Dautzenberg& d'Hamonville, 1887) Vietnam, Lang Son24 mm
Pleuropoma nonouensis M.C. Neal, 1934 Hawaii
Tristramia notata (L. Pfeiffer, 1856) Veracruz, Mexico
Alcadia novogranadensis B. Hausdorf, 2006
Alcadia nuda (R. Arango in L. Pfeiffer, 1866) Cuba
Pleuropoma oahuensis H.A. Pilsbry& C.M. Cooke, 1908 Hawaii