| Abra | Semelidae | Tellinoidea | Angulus | Tellininae | Tellinidae | Tellinoidea | ||
| Acamptogenotia | Clathurellinae | Conidae | Conoidea | Angusticardo | Sportellidae | Cyamioidea | ||
| Acanthina | Ocenebrinae | Muricidae | Muricoidea | Anisocorbula | Corbulinae | Corbulidae | Myoidea | |
| Acanthocardia | Cardiinae | Cardiidae | Cardioidea | Anisodonta | Sportellidae | Cyamioidea | ||
| Acantholabia | Muricinae | Muricidae | Muricoidea | Anodontia | Milthinae | Lucinidae | Lucinoidea | |
| Acanthotrophon | Muricopsinae | Muricidae | Muricoidea | Anomalocardia | Chioninae | Veneridae | Veneroidea | |
| Acar | Arcinae | Arcidae | Arcoidea | Anomalofusus | Fusininae | Fasciolariidae | Columbelloidea | |
| Aciculiscala | Epitoniinae | Epitoniidae | Janthinoidea | Anomia | Anomiidae | Anomioidea | ||
| Acirsa | Epitoniinae | Epitoniidae | Janthinoidea | Antalis | Dentaliidae | Dentaliida | Scaphopoda | |
| Aclis | Aclididae | Eulimoidea | Antephalium | Phaliinae | Cassidae | Tonnoidea | ||
| Acmaea | Acmaeinae | Acmaeidae | Patelloidea | Antigona | Venerinae | Veneridae | Veneroidea | |
| Acrilla | Epitoniinae | Epitoniidae | Janthinoidea | Antiguraleus | Crassispirinae | Turridae | Conoidea | |
| Acrocoelum | Mathildidae | Architectonicoidea | Antillophos | Photinae | Buccinidae | Buccinoidea | ||
| Acrocolpus | Bullidae | Bulloidea | Antimelatoma | Cochlespirinae | Turridae | Conoidea | ||
| Acroloxus | Acroloxidae | Acroloxoidea | Antiplanes | Cochlespirinae | Turridae | Conoidea | ||
| Acrostemma | Cylichnidae | Acteonoidea | Aphanitoma | Clathurellinae | Conidae | Conoidea | ||
| Acrosterigma | Trachycardiinae | Cardiidae | Cardioidea | Aphera | Cancellariinae | Cancellariidae | Mitroidea | |
| Actaeopyramis | Amathininae | Pyramidellidae | Pyramidelloidea | Aphrodina | Pitarinae | Veneridae | Veneroidea | |
| Acteocina | Cylichnidae | Acteonoidea | Apicula | Turritellinae | Turritellidae | Cerithioidea | ||
| Acteon | Acteoninae | Acteonidae | Acteonoidea | Apiocypraea | Erosariinae | Cypraeidae | Cypraeoidea | |
| Acutostrea | Crassostreinae | Ostreidae | Ostreoidea | Apiotoma | Cochlespirinae | Turridae | Conoidea | |
| Admete | Admetinae | Cancellariidae | Mitroidea | Apixystus | Trophoninae | Muricidae | Muricoidea | |
| Admetula | Admetinae | Cancellariidae | Mitroidea | Aplexa | Physidae | Physoidea | ||
| Adrana | Nuculaninae | Nuculanidae | Nuculanoidea | Aporrhais | Aporrhaiidae | Stromboidea | ||
| Aenator | Buccininae | Buccinidae | Buccinoidea | Aquilofusus | Fasciolariinae | Fasciolariidae | Columbelloidea | |
| Aequipecten | Chlamydinae | Pectinidae | Pectinoidea | Arca | Arcinae | Arcidae | Arcoidea | |
| Aesopus | Pyreninae | Columbellidae | Columbelloidea | Archicypraea | Bernayinae | Cypraeidae | Cypraeoidea | |
| Aetostreon | Exogyrinae | Ostreidae | Ostreoidea | Archimediella | Turritellinae | Turritellidae | Cerithioidea | |
| Aforia | Cochlespirinae | Turridae | Conoidea | Architectonica | Architectonicinae | Architectonicidae | Architectonicoidea | |
| Agaronia | Agaroniinae | Olividae | Volutoidea | Arcinella | Chamidae | Chamoidea | ||
| Agatha | Odostomellinae | Pyramidellidae | Pyramidelloidea | Arcopagia | Tellininae | Tellinidae | Tellinoidea | |
| Agatrix | Cancellariinae | Cancellariidae | Mitroidea | Arcopagiopsis | Tellininae | Tellinidae | Tellinoidea | |
| Agladrillia | Drilliidae | Muricoidea | Arcoperna | Crenellinae | Mytilidae | Mytiloidea | ||
| Agnocardia | Cardiinae | Cardiidae | Cardioidea | Arcopsis | Striarcinae | Noetiidae | Arcoidea | |
| Akera | Aplysinae | Aplysidae | Aplysioidea | Arcopsis | Noetiinae | Noetiidae | Arcoidea | |
| Alaba | Litiopidae | Cerithioidea | Arctica | Arcticidae | Arcticoidea | |||
| Alabina | Diastomatinae | Diastomatidae | Cerithioidea | Argobuccinum | Ranellinae | Ranellidae | Tonnoidea | |
| Alcithoe | Zidoninae | Volutidae | Volutoidea | Argopecten | Chlamydinae | Pectinidae | Pectinoidea | |
| Alectrion | Nassariinae | Nassariidae | Buccinoidea | Argyromya | Pholadomyidae | Pholadomyoidea | ||
| Alia | Columbellinae | Columbellidae | Columbelloidea | Arietites | Arietitidae | Ammonoida | ||
| Allopagus | Kelliellidae | Glossoidea | Armenica | Mentissoidinae | Clausiliidae | Clausilioidea | ||
| Alocospira | Ancillinae | Olividae | Volutoidea | Asaphinella | Psammobiinae | Psammobiidae | Tellinoidea | |
| Alvania | Rissoinae | Rissoidae | Rissooidea | Asaphis | Psammobiinae | Psammobiidae | Tellinoidea | |
| Alveinus | Kelliellidae | Glossoidea | Aspella | Muricinae | Muricidae | Muricoidea | ||
| Amaea | Epitoniinae | Epitoniidae | Janthinoidea | Aspidopholas | Martesiinae | Pholadidae | Pholadoidea | |
| Amalda | Ancillinae | Olividae | Volutoidea | Assiminea | Assimineinae | Assimineidae | Rissooidea | |
| Amaurellina | Ampullospirinae | Ampullinidae | Naticoidea | Astarte | Astartinae | Astartidae | Astartoidea | |
| Amauropsina | Polinicidae | Naticoidea | Astele | Calliostomatinae | Cirridae | Cirroidea | ||
| Amauropsis | Ampullospirinae | Ampullinidae | Naticoidea | Asthenotoma | Clathurellinae | Conidae | Conoidea | |
| Amblychilepas | Fissurellinae | Fissurellidae | Fissurelloidea | Astraea | Turbininae | Turbinidae | Trochoidea | |
| Americardia | Fraginae | Cardiidae | Cardioidea | Astralium | Turbininae | Turbinidae | Trochoidea | |
| Amiantis | Pitarinae | Veneridae | Veneroidea | Astyris | Pyreninae | Columbellidae | Columbelloidea | |
| Amoria | Scaphellinae | Volutidae | Volutoidea | Atactodea | Mesodesmatinae | Mesodesmatidae | Mactroidea | |
| Amphobola | Amphibolidae | Amphiboloidea | Ataxocerithiu, | Cerithiellinae | Cerithiopsidae | Ptenoglossa | ||
| Ampulla | Scaphellinae | Volutidae | Volutoidea | Athleta | Athletidae | Volutoidea | ||
| Ampullella | Ampullospirinae | Ampullinidae | Naticoidea | Atilia | Columbellinae | Columbellidae | Columbelloidea | |
| Ampullina | Ampullospirinae | Ampullinidae | Naticoidea | Atopodonta | Pitarinae | Veneridae | Veneroidea | |
| Ampullinopsis | Ampullospirinae | Ampullinidae | Naticoidea | Atractodon | Buccininae | Buccinidae | Buccinoidea | |
| Ampullospira | Ampullospirinae | Ampullinidae | Naticoidea | Atrina | Pinnidae | Pinnoidea | ||
| Amuletum | Turrinae | Turridae | Conoidea | Aturia | Aturiidae | Nautiloidea | Cephalopoda | |
| Amusium | Propeamussiidae | Pectinoidea | Atys | Haminoeinae | Haminoeidae | Acteonoidea | ||
| Amyclina | Nassariinae | Nassariidae | Buccinoidea | Aulacomya | Mytilinae | Mytilidae | Mytiloidea | |
| Amygdalum | Modiolinae | Mytilidae | Mytiloidea | Aurelianella | Diastomatinae | Diastomatidae | Cerithioidea | |
| Anachis | Pyreninae | Columbellidae | Columbelloidea | Austrocarina | Borsoniinae | Conidae | Conoidea | |
| Anadara | Anadarinae | Arcidae | Arcoidea | Austrocypraea | Erosariinae | Cypraeidae | Cypraeoidea | |
| Anapella | Davilinae | Mesodesmatidae | Mactroidea | Austrofusus | Buccininae | Buccinidae | Buccinoidea | |
| Anazola | Agaroniinae | Olividae | Volutoidea | Austroharpa | Harpinae | Harpidae | Muricoidea | |
| Anchura | Aporrhaiidae | Stromboidea | Austroliotia | Liotiinae | Turbinidae | Trochoidea | ||
| Ancilla | Ancillinae | Olividae | Volutoidea | Austrolithes | Fusininae | >Fasciolariidae | Columbelloidea | |
| Ancillarina | Ancillinae | Olividae | Volutoidea | Austromitra | Costellariidae | Mitroidea | ||
| Ancillista | Ancillinae | Olividae | Volutoidea | Austrotoma | Clavatulinae | Turridae | Conoidea | |
| Ancillus | Ancillinae | Olividae | Volutoidea | Austrotriton | Cymatinae | Ranellidae | Tonnoidea | |
| Ancistrolepis | Ancistrolepidinae | Buccinidae | >Buccinoidea | Avicularium | Aviculariidae | Tridacnoidea | ||
| Ancistrosyrinx | Cochlespirinae | Turridae | Conoidea | Aviculoperna | Pteriidae | Pterioidea | ||
| Ancyloceras | Ancyloceratidae | Ammonoida | Axelella | Cancellariinae | Cancellariidae | Mitroidea | ||
| Andoniopsis | Siphopsinae | Conidae | Conoidea | Axinactis | Glycymeridinae | Glycymerididae | Limopsoidea | |
| Aneurystoma | Cancellariinae | Cancellariidae | Mitroidea | Azorinus | Solecurtidae | Tellinoidea | ||
| Angaria | Angariinae | Turbinidae | Trochoidea | |||||