Crepidula lirata (FOSSIL) T.A. Conrad, 1833 †
Sigapatella maccoyi (FOSSIL) (H.H. Suter, 1917 †)
Crepidula maculosa T.A. Conrad, 1846
Calyptraea mamillaris W.J. Broderip, 1834
Sigapatella mapalia (FOSSIL) J. Marwick, 1929 †
Crucibulum marense N.E. Weisbord, 1962
Crepidula margarita L.R.L. Simone, 2006
Crepidula marginalis (W.J. Broderip, 1834)
Crepidula matajiroi (FOSSIL) J. Makiyama, 1957 †
Maoricrypta monoxyla (R.P. Lesson, 1831)
Crucibulum monticulus S.S. Berry, 1969
Crepidula moulinsii A. Michaud, 1829
Crucibulum multilineatum (FOSSIL) T.A. Conrad, 1842 †
Crepidula mytiloidea (FOSSIL) L.M.D. Bellardi& O.G. Michelotti, 1840 †
Crepidula naticarum M.B. Williamson, 1905
Crepidula navia (FOSSIL) M. Yokoyama, 1925 †
Crepidula navicella (R.P. Lesson, 1831)
Crepidula navicula O.A.L. Mörch, 1877
Crepidula nidatoriensis (FOSSIL) Y. Otuka, 1934 †
Crepidula nivea C.B. Adams, 1852
Crepidula norrisiarum (M.B. Williamson, 1905)
Sigapatella novaezelandiae (R.P. Lesson, 1831)
Sigapatella nukumaruana (FOSSIL) B.A. Marshall, 2003 †
Crepidula nummaria A.A. Gould, 1846
Trochita occidentalis (FOSSIL) Gray, 1850 †
Crepipatella occulta Veliz, H. Winkler, Guisados& R. Collin, 2012
Bostrycapulus odites R. Collin, 2005
Sigapatella ohopeana (FOSSIL) B.A. Marshall, 2003 †
Crepidula onyx Sowerby, 1824
Crepipatella orbiculata (W.H. Dall, 1919)
Trochita ornata (FOSSIL) B. de Basterot, 1825 †
Sigapatella otamatea (FOSSIL) C.R. Laws, 1944 †
Crepidula parisiensis (FOSSIL) A.E.M. Cossmann, 1883 †
Trochita parvula (FOSSIL) R.A. Philippi, 1887 †
Sigapatella patulosa (FOSSIL) Powell & J.A. Bartrum,1929 †