Ledella aberrata J.A. Allen & A. Sanders,1996
Polidevcia abrupta (FOSSIL) (J.B.M. Dana, 1847 †)
Saccella acapulcensis (H.A. Pilsbry & H.N. Lowe,1932)
Nuculana acinacea T. Habe, 1958
Scaeoleda acinaciformis (FOSSIL) (R. Tate, 1886 †)
Ledella acinula (W.H. Dall, 1890)
Saccella acrita (W.H. Dall, 1908)
Saccella acuminata (FOSSIL) (von Buch, 1845 †)
Nuculana acuta (T.A. Conrad, 1831)
Saccella acuticauda (FOSSIL) (G.B. Pritchard, 1901 †)
Adrana aegra (FOSSIL) A.A. Olsson, 1964 †
Calorhadia aequalis (FOSSIL) (T.A. Conrad, 1833 †)
Ledella aequatorialis (K.H.J. Thiele& S.G.A. Jaeckel, 1931)
Polidevcia aequilata (FOSSIL) Guskov, 1984 †
Jupiteria agapea (W.H. Dall, 1908)
Adrana agronomica (FOSSIL) C.J. Maury, 1924 †
Nuculana aikawai T. Habe, 1958
Jupiteria aipeia (FOSSIL) W.P. Woodring, 1973 †
Nuculana akidota (FOSSIL) D.T. Dockery, 1982 †
Saccella alaeformis (FOSSIL) (W.M. Gabb, 1869 †)
Calorhadia albirupina (FOSSIL) †
Adrana aldrichiana (FOSSIL) G.F. Harris, 1895 †
Borissia alferovi (FOSSIL) (Slodkewitsch, 1938 †)
Meganuculana alleni (FOSSIL) K. Amano & B.W. Jenkins,2017 †
Nuculana alpina (FOSSIL) H. Winkler, 1859 †
Saccella amelga (FOSSIL) (E.W.J. Moore, 1963 †)
Nuculana anakena B.K. Raines & M. Huber,2012
Saccella andrewi (FOSSIL) J. Marwick, 1931 †
Parayoldiella angulata Z.A. Filatova& A.A. Schileyko, 1985
Australoportlandia antarctica (FOSSIL) Zinsmeister, 1984 †
Nuculana antarctirostrata (FOSSIL) J.D. Stilwell & al.,2004 †
Polidevcia antequadrata (FOSSIL) C.O. Waterhouse, 1964 †
Ledellina anteroplana Z.A. Filatova& A.A. Schileyko, 1984
Poroleda antiqua (FOSSIL) J. Marwick, 1942 †
Nuculana approximans B. Prashad, 1932