Phrantela annamurrayae W.F. Ponder & K.B. Clark,1993
Pyrgula annulata (C. Linnaeus, 1767)
Prososthenia annulifera (FOSSIL) Š. Brusina, 1884 †
Fluvidona anodonta C. Hedley & C.T. Musson,1892
Hadopyrgus anops F.M. Climo, 1974
Hydrobia antarctica R.A. Philippi, 1868
Pseudamnicola anteisensis (P. Bérenguier, 1882)
Hadziella anti H. Schütt, 1960
Chilopyrgula antirriona (FOSSIL) Schütt, 1986 †
Socenia antonellae (FOSSIL) D. Esu & O. Girotti,2015 †
Caspia antoninae (FOSSIL) Roshka, 1973 †
Sarajana apfelbecki (K. Brancsik, 1888)
Micromelania applanata (FOSSIL) (A. Fuchs, 1873 †)
Fonscochlea aquatica W.F. Ponder, R. Hershler& B.W. Jenkins, 1989
Nematurella aquensis (FOSSIL) (Degrange-Touzin, 1892 †)
Hydrobia aquitanica (FOSSIL) Degrange-Touzin, 1892 †
Bythiospeum ara (D. Geyer, 1905)
Arabiella arabica (FOSSIL) D. Kadolsky, M. Harzhauser& T.A. Neubauer, 2015 †
Caspiohydrobia aralensis Y.I. Starobogatov& S.I. Andreeva, 1981
Valvatamnicola archangelskii (V.I. Zhadin, 1952)
Islamia archeducis H.D. Boeters & J. Beckmann,2007
Pyrgulopsis archimedis S.S. Berry, 1947
Pyrgula archimedis (FOSSIL) A. Fuchs, 1870 †
Guadiella arconadae (H.D. Boeters, 2003)
Leiorhagium aremuum M. Haase & S. Zielske,2015
Marstonia arga F.G. Thompson, 1977
Pyrgulopsis arizonae D.W. Taylor, 1987
Tanousia arminiensis (FOSSIL) (E. Jekelius, 1932 †)
Pseudamnicola artanensis C.R. Altaba, 2007
Bythiospeum articense R. Bernasconi, 1985
Pseudamnicola arvernensis (FOSSIL) (Bouillet, 1835 †)
Austropyrgus aslini A. Clark, W.B. Miller& W.F. Ponder, 2003
Pyrgula aspera (FOSSIL) Š. Brusina, 1878 †
Corrosella astierii (D. Dupuy, 1851)
Turricaspia astrachanica (Pirogov, 1971)