Pyreneola abyssicola (J.W. Brazier, 1877) Papua New Guinea34 mm
Aoteatilia acicula (H.H. Suter, 1908) New Zealand
Strombinella acuformis (FOSSIL) W.H. Dall, 1896 † Dominican Republic, Valverde
Mitrella acuminata K.T. Menke, 1843 Australia, Albany14 mm
Amphissa acuminata (E.A. Smith, 1915) Brazil, Sao Paulo13 mm
Amphissa acutecostata (R.A. Philippi, 1844) Ireland, Rockall trough7 mm
Parvanachis adamsi M. De Maintenon, 2014 Panama Bay
Nassarina adamsi (G.W. Tryon, 1883)
Columbella adansoni K.T. Menke, 1853 Gabon, Sao Tomé Island16 mm
Antimitrella adela (K.H.J. Thiele, 1925) South Africa
Anachis adelinae (G.W. Tryon, 1883) Ecuador7,3 mm
Sulcomitrella adversa K. Monsecour& D. Monsecour, 2016
Mitrella aemulata E. Rolán, 2005 Annobon Island7,7 mm
Zafra aequatorialis (K.H.J. Thiele, 1925)
Mitrella aesopiformis K. Monsecour& D. Monsecour, 2016
Mitrella africana E. Rolán, 2005 Gulf of Guinea4,5 mm
Mitrella agatha (J.C. Melvill, 1904) Gulf of Oman
Mitrella agenta (FOSSIL) M. Harzhauser& T. Kowalke, 2002 † Austria, Oberösterreich, Linz
Sulcomitrella aikeni (M. Lussi, 2009) Park Rynie, Natal, South Africa12,3 mm
Nitidella alaperdicis L.A. Reeve Jamaica11,7 mm
Suturoglypta albella (C.B. Adams, 1850) Bahamas
Costoanachis albicostata K. Monsecour& D. Monsecour, 2016
Graphicomassa albina (L.C. Kiener, 1841) Philippines, Aliguay Island11,5 mm
Mitrella albocaudata (E.A. Smith, 1884)
Mitrella albofulvata J. Drivas & M. Jay, 1990 Réunion7,5 mm
Mokumea albomarginata (Ohamoto & T. Habe, 1979) Japan, Kotoga beach7 mm
Anachis albonodosa (P.P. Carpenter, 1857) Costa Rica3 mm
Mokumea albovittata (H. de Souza Lopes, A.C. dos Santos Coelho& P.d. Cardoso, 1965) Brazil, Salvador Bahia3 mm
Mitrella albuginosa (L.A. Reeve, 1859) South Africa, Jeffreys Bay10 mm
Mitrella albuginosa bella (L.A. Reeve, 1859) Philippines, Aliguay Island12 mm
Costoanachis alcazari Ortea & Espinosa, 2017
Strombina aldrichi (FOSSIL) C.J. Maury, 1910 † Florida
Aesopus algoensis (G.B. III Sowerby, 1892) South Africa7,8 mm
Decipifus algoensis (K.H.J. Thiele, 1925)
Anachis aliceae (P.M. Pallary, 1900) Strait of Gibraltar8 mm