Seila mundula G.P. Deshayes, 1864
Cerithiopsis munita P.P. Carpenter, 1864
Joculator murciai A. Cecalupo & I. Perugia,2014
Zaclys murdochi B.A. Marshall, 1978
Horologica musii C. Chen, C.F. Tseng& L.C. Lo, 2012
Joculator mygaki M. Jay & J. Drivas, 2002
Joculator myia (M. Jay & J. Drivas,2002)
Potenatomus nanus (C.F. Laseron, 1951)
Seila natalensis E.A. Smith, 1914
Spinoseila necopinata (FOSSIL) P.A. Maxwell, 1992 †
Cerithiopsina necropolitana (FOSSIL) (P. Bartsch, 1911 †)
Cerithiopsis neglecta (C.B. Adams, 1852)
Prolixodens nicolayae M. Jay & J. Drivas, 2002
Seila nigrofusca C.F. Laseron, 1951
Cerithiopsis nina P. Bartsch, 1915
Joculator nitidus A. Cecalupo & I. Perugia,2012
Cubalaskeya nivea (M.J. Faber, 2007)
Horologica nodosa A. Cecalupo & I. Perugia,2012
Cerithiopsis nofronii B. Amati, 1987
Synthopsis noninii A. Cecalupo & I. Perugia,2012
Cerithiopsis nosimea J.T. Kuroda, 1946
Synthopsis noumeaensis Cecalupo & Perugia, 2017
Zaclys nuetzeli (FOSSIL) Lauridsen & Schnetler,2014 †
Cerithiopsis nutzeli M. Jay & J. Drivas, 2002
Synthopsis nutzeli A. Cecalupo & I. Perugia,2012
Cerithiopsis oaxacana L.G. Hertlein & A.M. Strong,1951
Krachia obeliscoides (J.G. Jeffreys, 1885)
Prolixodens obesa Cecalupo & Perugia, 2017
Cerithiopsis obesula M.E.J. Bucquoy, P. Dautzenberg& G.F. Dollfus, 1882
Prolixodens obscura (A. Cecalupo & I. Perugia,2012)
Joculator obscurus A. Cecalupo & I. Perugia,2012
Joculator obsoletus A. Cecalupo & I. Perugia,2012
Joculator occultus A. Cecalupo & I. Perugia,2012
Pilaflexis oculis C.F. Laseron, 1951
Prolixodens oleagina Cecalupo & Perugia, 2017