Opinions from A. A. Olsson 1922
- 'Abra triangulata belongs to Abra'
- 'Actaeon costaricensis belongs to Actaeon'
- 'Acteocina (Cylichnella) triticumtritonis belongs to Acteocina (Cylichnella)'
- 'Acteocina bullata costaricana belongs to Acteocina bullata'
- 'Agriopoma gatunensis is recombined as Callocardia (Agriopoma) gatunensis'
- 'Alaba turrita belongs to Alaba' according to Guppy 1896
- 'Alectrion losquemadica belongs to Alectrion'
- 'Alectrion merenda belongs to Alectrion'
- 'Alectrion ranuncula belongs to Alectrion'
- 'Amphidesma laevis is recombined as Semele laevis'
- 'Amusium bocasense belongs to Amusium'
- 'Anomia simplex belongs to Anomia'
- 'Antigona harrisiana belongs to Antigona'
- 'Arca (Barbatia) mauryae belongs to Arca (Barbatia)'
- 'Arca (Scapharca) costaricensis belongs to Arca (Scapharca)'
- 'Arca (Scapharca) honensis belongs to Arca (Scapharca)'
- 'Arca (Scapharca) pittieri is recombined as Arca (Cunearca) pittieri'
- 'Arca auriculata is recombined as Arca (Scapharca) auriculata'
- 'Arca candida is recombined as Arca (Calloarca) candida'
- 'Arca dariensis is recombined as Arca (Scapharca) dariensis'
- 'Arca decussata is recombined as Glycymeris decussatus'
- 'Arca golfoyaquensis belongs to Arca' according to Maury 1917
- 'Arca golfoyaquensis is recombined as Arca (Scapharca) golfoyaquensis'
- 'Arca hindsi belongs to Arca'
- 'Arca macdonaldi is recombined as Arca (Noetia) macdonaldi'
- 'Arca occidentalis belongs to Arca'
- 'Arca umbonata belongs to Arca'
- 'Artemis acetabulum is recombined as Dosinia acetabulum'
- 'Artemis subquadrata belongs to Artemis' according to Hanley 1844
- 'Artemis subquadrata is recombined as Cyclinella subquadrata'
- 'Avicula inornata is recombined as Pteria inornata'
- 'Borsonia cocoensis belongs to Borsonia'
- 'Buccinum flammeum belongs to Buccinum' according to Linnaeus 1758
- 'Buccinum flammeum is recombined as Cassis flammea'
- 'Calliostoma castilla belongs to Calliostoma'
- 'Calloarca was reranked as Arca (Calloarca) and belongs to Arca'
- 'Cancellaria (Aphera) islacolonis is recombined as Cancellaria islacolonis'
- 'Cancellaria barretti belongs to Cancellaria'
- 'Cancellaria dariena belongs to Cancellaria'
- 'Cancellaria epistomifera belongs to Cancellaria'
- 'Cancellaria rowelli belongs to Cancellaria'
- 'Cancellaria toroensis belongs to Cancellaria'
- 'Cardita conradiana belongs to Cardita' according to Gabb 1881
- 'Cardita conradiana is recombined as Venericardia (Pleuromeris) conradiana'
- 'Cardita matima belongs to Cardita'
- 'Cardita scabricostata is recombined as Venericardia scabricostata'
- 'Cardium (Trachycardium) dominicense belongs to Cardium (Trachycardium)'
- 'Cardium (Trachycardium) stiriatum belongs to Cardium (Trachycardium)'
- 'Cardium heredium belongs to Cardium'
- 'Cardium medium is recombined as Cardium (Fragum) medium'
- 'Cardium serratum is recombined as Cardium (Laevicardium) serratum'
- 'Cardium spinosum is recombined as Cardium (Papyridea) spinosum'
- 'Caryatis guppyana is recombined as Pitaria guppyana'
- 'Caryatis guppyana belongs to Caryatis' according to Gabb 1881
- 'Cassidaria laevigata is recombined as Sconsia laevigata'
- 'Cassis monilifera is recombined as Phalium moniliferum'
- 'Cassis sulcifera belongs to Cassis'
- 'Cerithium costaricensis belongs to Cerithium'
- 'Chama antiquata belongs to Chama' according to Guppy 1866
- 'Chama antiquata is recombined as Echinochama antiquata'
- 'Chama congregata belongs to Chama'
- 'Chione costaricensis belongs to Chione'
- 'Chione hotelensis belongs to Chione'
- 'Chione rowleei belongs to Chione'
- 'Chione ulocyma holocyma belongs to Chione ulocyma' according to Brown and Pilsbry 1911
- 'Chione ulocyma holocyma is recombined as Chione holocyma'
- 'Chlorostoma costaricensis belongs to Chlorostoma'
- 'Clava alajuela belongs to Clava'
- 'Clava costaricana belongs to Clava'
- 'Columbella ambigua belongs to Columbella' according to Guppy 1866
- 'Columbella ambigua is recombined as Strombina ambigua'
- 'Conus (Cheliconus) tortuosopunctatus is recombined as Conus tortuosopunctatus'
- 'Conus (Chelyconus) tortuosostriatus belongs to Conus (Chelyconus)'
- 'Conus burckhardti belongs to Conus'
- 'Conus concavitectum belongs to Conus'
- 'Conus gracilissimus belongs to Conus'
- 'Conus granozonatus belongs to Conus'
- 'Conus imitator belongs to Conus'
- 'Conus limonensis belongs to Conus'
- 'Conus marginatus belongs to Conus'
- 'Conus molis belongs to Conus'
- 'Conus planiliratus belongs to Conus'
- 'Conus planiliratus bocasensis belongs to Conus planiliratus'
- 'Conus proteus belongs to Conus'
- 'Conus recognitus belongs to Conus'
- 'Conus stenostoma is corrected as Conus stenostomus and belongs to Conus'
- 'Coralliophila gatunensis is a subjective synonym of Solenosteira dalli'
- 'Corbula dietziana belongs to Corbula' according to C. B. Adams 1852
- 'Corbula dietziana belongs to Corbula'
- 'Corbula oropendula belongs to Corbula'
- 'Corbula orosi belongs to Corbula'
- 'Corbula vieta belongs to Corbula'
- 'Corbula viminea belongs to Corbula'
- 'Crassatellites (Crassinella) bowdenensis belongs to Crassatellites (Crassinella)'
- 'Crassatellites (Crassinella) midiensis belongs to Crassatellites (Crassinella)'
- 'Crassatellites reevei belongs to Crassatellites'
- 'Crepidula plana belongs to Crepidula'
- 'Crepitacella limonensis belongs to Crepitacella'
- 'Cyclinella subquadrata quitana belongs to Cyclinella subquadrata'
- 'Cypraea dominicensis belongs to Cypraea'
- 'Cypraea parisimina belongs to Cypraea'
- 'Cythara terminula costaricensis belongs to Cythara terminula'
- 'Cytharella limata belongs to Cytharella'
- 'Dentalium (Fissidentalium) uscarianum belongs to Dentalium (Fissidentalium)'
- 'Dentalium bocasensis belongs to Dentalium'
- 'Diplodonta collina belongs to Diplodonta'
- 'Drillia aquansis belongs to Drillia'
- 'Drillia carruca belongs to Drillia'
- 'Drillia citria belongs to Drillia'
- 'Drillia coccos belongs to Drillia'
- 'Drillia cocosina belongs to Drillia'
- 'Drillia cristobali belongs to Drillia'
- 'Drillia limonensis belongs to Drillia'
- 'Drillia limonica belongs to Drillia'
- 'Drillia lithocolletoides belongs to Drillia'
- 'Drillia moensis belongs to Drillia' according to Gabb 1881
- 'Drillia moensis belongs to Drillia'
- 'Drillia musa belongs to Drillia'
- 'Drillia theobroma belongs to Drillia'
- 'Drillia torosa aurantia is recombined as Drillia aurantia'
- 'Echinochama antiquata yaquensis belongs to Echinochama antiquata' according to Maury 1917
- 'Echinochama antiquata yaquensis is recombined as Echinochama yaquensis'
- 'Euchilodon morierei is recombined as Scobinella morierei'
- 'Fasciolaria gorgasiana belongs to Fasciolaria'
- 'Fusus miocosmius belongs to Fusus'
- 'Gafrarium (Gouldia) altum is recombined as Gafrarium altum'
- 'Gafrarium limonensis belongs to Gafrarium'
- 'Gastrochaena rotunda belongs to Gastrochaena' according to Dall 1915
- 'Gastrochaena rotunda belongs to Gastrochaena'
- 'Glycymeris canalis belongs to Glycymeris'
- 'Glycymeris carbasina belongs to Glycymeris'
- 'Glycymeris jamaicensis belongs to Glycymeris'
- 'Glycymeris lloydsmithi belongs to Glycymeris'
- 'Glycymeris trilobicostata is a subjective synonym of Glycymeris canalis'
- 'Glyphostoma dentiferum is corrected as Glyphostoma dentifera and belongs to Glyphostoma'
- 'Gratelupia mactropsis is recombined as Chione mactropsis'
- 'Latirus infundibulum belongs to Latirus'
- 'Latirus irazu belongs to Latirus'
- 'Latirus taurus belongs to Latirus'
- 'Leda (Adrana) dalliana belongs to Leda (Adrana)'
- 'Leda (Adrana) ensinoides belongs to Leda (Adrana)'
- 'Leda (Adrana) quitanensis belongs to Leda (Adrana)'
- 'Leda balboae belongs to Leda'
- 'Leda davilae belongs to Leda'
- 'Limea is corrected as Limaea and belongs to Bivalvia'
- 'Limea solida belongs to Limea' according to Dall 1898
- 'Limea solida is recombined as Limaea solida'
- 'Limopsis monilis belongs to Limopsis'
- 'Lophocardium was reranked as Protocardia (Lophocardium) and belongs to Protocardia'
- 'Lucina cristata is recombined as Tellidora cristata'
- 'Lucina quadrisulcata is recombined as Divaricella quadrisulcata'
- 'Lucina radians is recombined as Phacoides (Callucina) radians'
- 'Lucina trisulcata is recombined as Phacoides (Here) trisulcatus'
- 'Lutraria lineata is recombined as Labiosa lineata'
- 'Macoma (Psammacoma) panamensis belongs to Macoma (Psammacoma)' according to Dall 1900
- 'Macoma (Psammacoma) panamensis belongs to Macoma (Psammacoma)'
- 'Macoma (Tellina) gatunensis is recombined as Macoma (Psammacoma) gatunensis'
- 'Macoma costaricana belongs to Macoma'
- 'Mactra alata is recombined as Mactra (Mactrella) alata'
- 'Mactra exoleta belongs to Mactra' according to Garay 1837
- 'Mactra exoleta is recombined as Mactra (Mactrella) exoleta'
- 'Mactra lateralis is recombined as Mulinia lateralis'
- 'Mactra sincola belongs to Mactra'
- 'Malea elliptica belongs to Malea'
- 'Marginella avena belongs to Marginella'
- 'Marginella latissima belongs to Marginella'
- 'Marginella latissima pilsbryi belongs to Marginella latissima'
- 'Marginella leander belongs to Marginella'
- 'Marginella macdonaldi belongs to Marginella' according to Dall 1912
- 'Marginella macdonaldi belongs to Marginella'
- 'Marginella mindiensis belongs to Marginella' according to Cossmann 1913
- 'Marginella mindiensis belongs to Marginella'
- 'Marginella musacina belongs to Marginella'
- 'Meretrix dariena is recombined as Clementia dariena'
- 'Mesodesma costaricensis belongs to Mesodesma'
- 'Metis barba belongs to Metis'
- 'Metula cancellata belongs to Metula'
- 'Metula gabbi belongs to Metula'
- 'Metula harrisi belongs to Metula'
- 'Metula harrisi limonensis belongs to Metula harrisi'
- 'Mitra almagrensis belongs to Mitra' according to Toula 1911
- 'Mitra almagrensis belongs to Mitra'
- 'Mitra almagrensis coralliophila belongs to Mitra almagrensis'
- 'Mitra dariensis belongs to Mitra'
- 'Mitra longa belongs to Mitra'
- 'Mitra poas belongs to Mitra'
- 'Mitra rudis belongs to Mitra'
- 'Mitra swainsoni limonensis belongs to Mitra swainsoni'
- 'Mulinia lateralis sauryensis belongs to Mulinia lateralis'
- 'Murex cornurectus is recombined as Murex (Phyllonotus) cornurectus'
- 'Murex messorius belongs to Murex'
- 'Murex tulipa is recombined as Fasciolaria tulipa'
- 'Nassa northiae is recombined as Northia northiae'
- 'Natica guppiana is corrected as Natica guppyana and belongs to Natica'
- 'Natica subclausa is recombined as Polinices subclausa'
- 'Natica youngi belongs to Natica'
- 'Natica youngi cocleana belongs to Natica youngi'
- 'Nerita canrena is recombined as Natica canrena'
- 'Neritina (Smaragdia) viridemaris is recombined as Neritina viridemaris'
- 'Neverita nereidis belongs to Neverita' according to Maury 1917
- 'Neverita nereidis belongs to Neverita'
- 'Northia northiae miocenica belongs to Northia northiae'
- 'Nucula orbicella belongs to Nucula'
- 'Nucula tenuisculpta belongs to Nucula'
- 'Oliva brevispira belongs to Oliva'
- 'Oliva cylindrica belongs to Oliva'
- 'Oliva gatunensis belongs to Oliva'
- 'Oliva multicoides is recombined as Olivella muticoides'
- 'Oliva sayana immortua belongs to Oliva sayana'
- 'Oliva testacea costaricensis belongs to Oliva testacea'
- 'Olivella boussaci belongs to Olivella'
- 'Olivella goliath belongs to Olivella'
- 'Olivella limonensis belongs to Olivella'
- 'Olivella limonensis bocasensis belongs to Olivella limonensis'
- 'Ostrea megodon belongs to Ostrea'
- 'Pecten (Aequipecten) preglyptus belongs to Pecten (Aequipecten)'
- 'Pecten (Amusium) luna is recombined as Amusium luna'
- 'Pecten (Cyclopecten) oligolepis is recombined as Pecten oligolepis'
- 'Pecten (Flabellipecten) gatunensis is recombined as Pecten gatunensis'
- 'Pecten aotus belongs to Pecten'
- 'Pecten coralliphila belongs to Pecten'
- 'Pecten levicostatus is recombined as Pecten (Chlamys) levicostatus'
- 'Pecten macdonaldi belongs to Pecten'
- 'Pectunculus castaneus is recombined as Glycymeris castaneus'
- 'Peristernia insula belongs to Peristernia'
- 'Peristernia tortugera belongs to Peristernia'
- 'Petaloconchus sculpturatus belongs to Petaloconchus'
- 'Phacoides (Bellucina) actinus is recombined as Phacoides (Parvilucina) actinus'
- 'Phacoides (Lucinisca) costaricensis belongs to Phacoides (Lucinisca)'
- 'Phasianella mollis belongs to Phasianella'
- 'Phos beteyensis belongs to Phos'
- 'Phos elegans limonensis belongs to Phos elegans'
- 'Phos estrellensis belongs to Phos'
- 'Phos gatunensis belongs to Phos'
- 'Phos metuloides belongs to Phos'
- 'Phos mexicanus belongs to Phos'
- 'Phos moorei belongs to Phos'
- 'Phos moorei costaricensis belongs to Phos moorei'
- 'Phos subsemicostatus belongs to Phos'
- 'Pitaria (Lamelliconcha) hillii is recombined as Pitaria hillii'
- 'Pitaria boucaryensis belongs to Pitaria'
- 'Pitaria hillii musanica belongs to Pitaria hillii'
- 'Placunanomia lithobleta belongs to Placunanomia'
- 'Pleurotoma (Ancistrosyrinx) elegans is recombined as Ancistrosyrinx elegans'
- 'Pleurotoma albida is recombined as Turris albida'
- 'Pleurotoma consors is recombined as Drillia consors'
- 'Pleurotoma venusta is recombined as Drillia venusta'
- 'Plicatula marginata belongs to Plicatula'
- 'Polinices stanislasmeunieri belongs to Polinices'
- 'Porcellana cinerea is recombined as Cypraea cinerea'
- 'Protocardia costaricensis belongs to Protocardia'
- 'Protocardia gurabica is recombined as Protocardia (Lophocardium) gurabica'
- 'Psammacoma gatunensis costaricensis belongs to Psammacoma gatunensis'
- 'Psammosolen gatunensis costaricensis belongs to Psammosolen gatunensis'
- 'Ptychosalpinx dentalis belongs to Ptychosalpinx'
- 'Purpura nodulosa is recombined as Sistrum nodulosum'
- 'Purpura nodulosa belongs to Purpura' according to C. B. Adams 1845
- 'Pyrula consors is recombined as Melongena consors'
- 'Ranella crassa is recombined as Bursa crassa'
- 'Ringicula dominicana belongs to Ringicula'
- 'Sanguinolaria alouatta belongs to Sanguinolaria'
- 'Scapharca (Scapharca) actinophora is recombined as Arca (Scapharca) actinophora'
- 'Scapharca henekeni is recombined as Arca (Scapharca) henekeni'
- 'Scaphella costaricana belongs to Scaphella'
- 'Semele claytoni belongs to Semele'
- 'Semele sayi belongs to Semele'
- 'Siliquaria modesta belongs to Siliquaria' according to Dall 1881
- 'Siliquaria modesta belongs to Siliquaria'
- 'Siliquaria modesta limonensis belongs to Siliquaria modesta'
- 'Solarium granulatum is recombined as Architectonica granulata'
- 'Solecurtus gatunensis is recombined as Psammosolen gatunensis'
- 'Solenosteira chiriquiensis belongs to Solenosteira'
- 'Solenosteira dalli belongs to Solenosteira'
- 'Solenosteira vaughani belongs to Solenosteira' according to Dall 1903
- 'Solenosteira vaughani medioamericana belongs to Solenosteira vaughani'
- 'Spondylus chiriquiensis belongs to Spondylus'
- 'Spondylus gumanomocon belongs to Spondylus'
- 'Strigilla musanica belongs to Strigilla'
- 'Strombina cricamola belongs to Strombina'
- 'Strombina lessepsiana belongs to Strombina'
- 'Strombina matima belongs to Strombina'
- 'Strombus gatunensis belongs to Strombus'
- 'Strombus pugiloides belongs to Strombus'
- 'Tagelus cebus belongs to Tagelus'
- 'Tapes grus is recombined as Chione grus'
- 'Tellina (Merisca) nasua belongs to Tellina (Merisca)'
- 'Tellina (Phyllodina) lepidota is recombined as Tellina lepidota'
- 'Tellina (Scissula) cercadica is recombined as Tellina cercadica'
- 'Tellina costaricana belongs to Tellina'
- 'Tellina cristallina is recombined as Tellina (Arcopagia) crystallina'
- 'Tellina dariena belongs to Tellina'
- 'Tellina pisiformis is recombined as Strigilla pisiformis'
- 'Tellina rovala belongs to Tellina'
- 'Tellina umbra is recombined as Tellina (Angulus) umbra'
- 'Terebra (Acus) benthalis belongs to Terebra (Acus)' according to Dall 1889
- 'Terebra (Acus) benthalis is recombined as Terebra benthalis'
- 'Terebra (Acus) bipartita spirifera is recombined as Terebra spirifera'
- 'Terebra (Oxymeria) gatunensis is recombined as Terebra gatunensis'
- 'Terebra (Oxymeria) wolfgangi is recombined as Terebra wolfgangi'
- 'Terebra benthalis bocasensis belongs to Terebra benthalis'
- 'Terebra berlinerae belongs to Terebra'
- 'Terebra bipartita belongs to Terebra'
- 'Terebra costaricensis belongs to Terebra'
- 'Terebra estrellana belongs to Terebra'
- 'Terebra gausapata belongs to Terebra'
- 'Terebra haitensis belongs to Terebra'
- 'Terebra pumbriensis belongs to Terebra'
- 'Terebra spirifera midiensis belongs to Terebra spirifera'
- 'Terebra subsulcifera belongs to Terebra'
- 'Thracia (Cyathodonta) tristani belongs to Thracia (Cyathodonta)'
- 'Triton simillimus is recombined as Distortrix simillima'
- 'Trochus brevispina is recombined as Astralium brevispinum'
- 'Trochus caelatus is recombined as Astralium caelatum'
- 'Trochus conchyliophorus is recombined as Xenophora conchyliophora'
- 'Turbo exoletus is recombined as Turritella exoleta'
- 'Turbo saltus belongs to Turbo'
- 'Turricula taurina belongs to Turricula'
- 'Turricula terryi belongs to Turricula'
- 'Turritella altilira belongs to Turritella'
- 'Turritella altilira costaricensis belongs to Turritella altilira'
- 'Turritella exoleta limonensis belongs to Turritella exoleta'
- 'Turritella gatunensis belongs to Turritella'
- 'Turritella mimetes belongs to Turritella'
- 'Turritella oreodoxa belongs to Turritella'
- 'Typhis alatus belongs to Typhis'
- 'Typhis linguliferus costaricensis belongs to Typhis linguliferus'
- 'Venus (Chione) ulocyma is recombined as Chione ulocyma'
- 'Venus blandiana is recombined as Antigona blandiana'
- 'Venus circinata is recombined as Pitaria circinata'
- 'Venus maculata is recombined as Macrocallista maculata'
- 'Venus multicostata is recombined as Antigona multicostata'
- 'Venus rugosa belongs to Venus' according to Gmelin 1792
- 'Venus rugosa is recombined as Antigona rugosa'
- 'Venus tarquinia is recombined as Antigona tarquina'
- 'Vermetus papulosa is recombined as Serpulorbis papulosa'
- 'Voluta alfaroi belongs to Voluta'
- 'Volvula cylindrica belongs to Volvula'
- 'Xancus scopulus belongs to Xancus'
- 'Yoldia bocasensis belongs to Yoldia'