Tropidophora andrakarakarensis E. Fischer-Piette& A.M. Testud, 1973
Tropidophora andrapangana E. Fischer-Piette, F. Blanc& F. Salvat, 1969
Choanopomops andrewsae (C.M.F. Ancey, 1886)
Choanopoma andrewsi (C.M.F. Ancey, 1886)
Opisthosiphon andrewsi D.A. Welch, 1929
Opisthosiphon androsense H.A. Pilsbry, 1930
Chondropoma angustatum L. Pfeiffer
Annularia anomala (C.B. Adams, 1850)
Adamsiella antiguaense (R.J. Shuttleworth, 1858)
Pomatias antiquus (FOSSIL) (A. Brongniart, 1810 †)
Chondropoma antonense C. de la Torre & P. Bartsch,1938
Opisthosiphon apertum C. de la Torre& J. Henderson, 1920
Troschelvindex arangiana (J. Gundlachin L. Pfeiffer, 1857)
Diplopoma arangoi (M.L. Jaume, 1984)
Diplopoma architectonica (J. Gundlachin L. Pfeiffer, 1859)
Parachondria arcisensis Watters, 2016
Wrightudora arcticoronata (C. de la Torre& P. Bartsch, 1941)
Tessaripoma arenarium Watters, 2016
Juannularia arguta (L. Pfeiffer, 1858)
Juannularia arguta perplicata (J. Gundlach, 1857)
Adamsiella aripensis (R.J.L. Guppy, 1864)
Annularisca armasi (M.L. Jaume, 1984)
Parachondria armata (C.B. Adams, 1849)
Pomatias arneggensis (FOSSIL) Wenz, 1923 †
Annularisca arquesi C. de la Torre & P. Bartsch,1941
Tropidophora articulata (J.E. Gray, 1838)
Otopoma artuffeli F.P. Jousseaume, 1882
Cistulops arubana H.B. Baker, 1924
Tropidophora aspera (V.L.V. Potiez& A. Michaud, 1838)
Wrightudora asperata (C. de la Torre& P. Bartsch, 1941)
Chondropoma asperulum C.G. Aguayo, 1934
Chondropoma aspratile P.M.A. Morelet, 1873
Chondrothyrella assimilis (J. Gundlachin L. Pfeiffer, 1863)
Chondrothyrella assimilis gemma C. de la Torre & P. Bartsch,1938
Chondrothyrella assimilis guirensis C. de la Torre & P. Bartsch,1938