Spissatella lyellii (FOSSIL) (Sowerby, 1846 †)
Crassinella maldonadoensis H.A. Pilsbry, 1897 Uruguay5 mm
Hybolophus maleficae (FOSSIL) DeVries, 2016 † Peru, Ica, Pisco70 mm
Crassatella manifesta (FOSSIL) Berezovsky, 2010 † Ukraine54 mm
Crassatella maroimensis (FOSSIL) White, 1887 † Brazil, Sergipe
Crassinella marplatensis Z.J.A. De Castellanos,1970 East America
Eucrassatella marshalli (FOSSIL) A.W.B. Powell, 1931 †
Crassinella martinicensis (A.V.M.D. D'Orbigny,1853) Florida, Egmont Key2,4 mm
Marvacrassatella marylandica (FOSSIL) (T.A. Conrad, 1832 †) USA, Maryland
Eucrassatella maudensis (FOSSIL) (G.B. Pritchard, 1903 †) Australia, Western Australia, Dundas
Spissatella maxwelli (FOSSIL) K.S. Collins, D.M. Crampton& G. Hannah, 2014 †
Spissatella media (FOSSIL) J. Marwick, 1926 † New Zealand, Otago, Waitaki
Hybolophus mediamaricanus (FOSSIL) (J. Brown& H.A. Pilsbry, 1913 †) Panama
Eucrassatella mediamericana (FOSSIL) (J. Brown& H.A. Pilsbry, 1913 †) Panama, Panamá, Arraiján
Crassatella meganosensis (FOSSIL) Clark & Woodford, 1927 † USA, California, Contra Costa
Marvacrassatella melina (FOSSIL) (T.A. Conrad, 1832 †) USA, Maryland61 mm
Crassatella meridionalis (FOSSIL) W.C. Mansfield, 1929 † USA, Florida, Leon
Crassatella merriami (FOSSIL) C.S. Weaver, 1916 †
Salaputium micrum (J.C. Verco, 1895) South Australia
Crassinella midiensis (FOSSIL) A.A. Olsson, 1922 † Costa Rica, Limón, Talamanca
Anthonya mifunensis (FOSSIL) Tamura, 1977 † Japan, Shizuoka, Hamamatsu
Crassinella minor (FOSSIL) † USA, Alabama, Monroe
Crassatella mississippiensis (FOSSIL) T.A. Conrad, 1848 † USA, Mississippi80 mm
Crassatina modesta (C.B. Adams, 1869) Morocco, cap Cantin8 mm
Salaputium modestum (H. Adams, 1869) Senegal, Dakar12,1 mm
Nipponocrassatella nana (A. Adams & L.A. Reeve,1850) China, Zhejiang46 mm
Indocrassatella natalensis (K.H. Barnard, 1964) South Africa, Natal, Durban Bay12,7 mm
Eucrassatella navigatum (S.L. Lovén, 1846)
Fluctiger navigatus (C. Hedley, 1906)
Hybolophus nelsoni (FOSSIL) (Grzybowski, 1899 †) Peru, Payta
Crassatella neorhynchus (FOSSIL) A.A. Olsson, 1931 † Peru, Chira Valley
Crassatella neusensis (FOSSIL) L.W. Stephenson, 1923 †
Eucrassatella nipponensis (FOSSIL) M. Yokoyama, 1928 † Japan, Tokyo
Crassinella nuculiformis S.S. Berry, 1940 Ecuador, Manabi
Eucrassatella oblonga (FOSSIL) (J.E. Tenison-Woods,1876 †) Tasmania99 mm