Trochus anthracophilus (FOSSIL) F.A. Roemer, 1880 †
Cantharidus antipodum (J.B. Hombron& C.H. Jacquinot, 1854)
Oxystele antoni Herbert, 2015
Lirularia antoniae F. Rubio & E. Rolán, 1997
Trochus apicalis (FOSSIL) Moore †
Parminolia apicina (A.A. Gould, 1862)
Phasianotrochus apicinus (K.T. Menke, 1843)
Gibbula aquitanica (FOSSIL) A.E.M. Cossmann& M.A. Peyrot, 1917 †
Stomatella arabica A. Adams, 1854
Clanculopsis araonis (FOSSIL) (B. de Basterot, 1825 †)
Ozodochilus aratus (FOSSIL) Lycett †
Trochus arcotensis E. Forbes, 1846
Gibbula ardens (C.U.A. von Salis-Marschlins, 1793)
Gibbula ardens subcincta T.A. de M. Monterosato,1888
Charisma arenacea (G.B. Pritchard& J.H. Gatliff, 1902)
Diloma arida (H.J. Finlay, 1926)
Jujubinus armatus (FOSSIL) B.M. Landau, L. Ceulemans& F. Van Dingenen, 2016 †
Clanculus aroanis (FOSSIL) (B. de Basterot, 1825 †)
Calthalotia arruensis (Watson, 1880)
Trochus artensis P. Fischer, 1878
Pseudominolia articulata (A.A. Gould, 1861)
Phorcus articulatus (J.B.P.A. Lamarck, 1822)
Clelandella artilesi C. Vilvens, F. Swinnen& F. Déniz, 2011
Cantharidus artizona (A. Adams, 1853)
Stomatella asperulata (A. Adams, 1850)
Trochus athenasi (FOSSIL) Vasseur, 1881 †
Stomatia atlantica F. Nordsieck, 1980
Phorcus atratus (W. Wood, 1828)
Phorcus atratus selvagensis F.F. Talavera, 1978
Phorcus atratus trappei F. Nordsieck, 1982
Clanculus atricatena J.R. le B. Tomlin, 1921
Clanculus atropurpureus Gould, 1849
Tosatrochus attenuatus (I.H. Jonas, 1844)
Trochus attrochus (FOSSIL) Hudleston †
Clanculus atypicus (T. Iredale, 1912)