Ra
- Rachipteron
- Radiacmea
- Radinista
- Radiolucina
- Radix
- Radobornia
- Radsia
- Raeta
Rahula Gadwin-Austen, 1907
- Rahula moolenbeeki Maassen, 2000
- Rahula raricostulata (Smith, 1894)
Mollusca → Gastropoda → Pulmonata → Helicarionoidea → Helicarionidae → Helicarioninae
- Ramogenia
- Ramphopoma
- Ranella
- Ranellidae
- Ranfurlya
- Rangia
- Ransoniella
- Ranularia
- Rapa
- Rapana
- Rapanuia
- Raphitoma
- Raphitomidae
- Rasta
- Rastodens
- Rastodentidae
- Rathouisiidae
Re
- Recluzia
- Rectidens
- Rectilabrum
- Rectiplanes
- Redicirce
- Regterenia
- Rehderiella
- Reishia
- Relichna
- Reloncavia
- Rengea
- Resania
- Reticulatus
- Reticulidia
- Retidrillia
- Retifusus
- Retigyra
- Retilaskeya
- Retimohnia
- Retizafra
- Retrotapes
- Retroterra
- Retrotortina
- Retusa
- Retusidae
- Reymondia
- Reynellona
Rh
- Rhabdidae
- Rhabdoherpia
- Rhabdus
- Rhachistia
- Rhagada
- Rhamphidonta
- Rhapinema
- Rhincoryne
- Rhinoclama
- Rhinoclavis
- Rhinocoryne
- Rhinodiaphana
- Rhipidodonta
- Rhipidoherpia
- Rhipidoherpiidae
- Rhizochilus
- Rhizoridae
- Rhizorus
- Rhodacme
- Rhodacmea
- Rhodope
- Rhodopetala
- Rhodopetoma
- Rhodopidae
- Rhombinella
- Rhombipoma
- Rhomboidella
- Rhomboxiphus
- Rhombuniopsis
- Rhopalomenia
- Rhopalomeniidae
- Rhophodon
- Rhynchopelta
- Rhynchotrochus
- Rhytida
- Rhytidarex
- Rhytididae
- Rhytidoidea
Ri
- Ribriarca
- Ricinula
- Rictaxiella
- Rictaxis
- Rimella
- Rimellidae
- Rimellopsis
- Rimosodaphnella
- Rimula
- Ringicula
- Ringiculidae
- Ringiculoidea
- Ringiculoides
- Ringiculopsis
- Ripalania
- Risbecia
- Risellopsis
- Risomurex
- Rissoa
- Rissoella
- Rissoellidae
- Rissoelloidea
- Rissoidae
- Rissoina
- Rissolina
- Rissooidea
- Rissopsetia
- Rissopsis
- Rivomarginella
- Rivularia
- Rixa
Ro
- Robaia
- Robertsiella
- Robillardia
- Roblinella
Roboastra Bergh, 1877
- Roboastra caboverdensis Pola, Cervera & Gosliner, 2003
- Roboastra ernsti Pola, Padula, Gosliner & Cervera, 2014
- Roboastra europaea García-Gómez, 1985
- Roboastra gracilis (Bergh, 1877)
- Roboastra leonis Pola, Cervera & Gosliner, 2005
- Roboastra luteolineata (Baba, 1936)
- Roboastra nikolai Pola, Padula, Gosliner & Cervera, 2014
- Roboastra ricei Pola, Cervera & Gosliner, 2008
- Roboastra rubropapulosa (Bergh, 1905)
- Roboastra tentaculata (Pola, Cervera & Gosliner, 2005)
- Roboastra tigris Farmer, 1978
Mollusca → Gastropoda → Nudibranchia → Polyceroidea → Polyceridae → Nembrothinae
- Robsonella
- Rocellaria
- Rochefortia
- Rochefortina
- Rocroithys
- Rolandia
- Rolandiella
- Rolaniconus
- Rondeletiola
- Roperia
Rossia Owen, 1834
- Rossia brachyura Verrill, 1883
- Rossia bullisi Voss, 1956
- Rossia glaucopis Lovén, 1845
- Rossia macrosoma (Delle Chiaje, 1830)
- Rossia megaptera Verrill, 1881
- Rossia moelleri Steenstrup, 1856
- Rossia mollicella Sasaki, 1920
- Rossia pacifica Berry, 1911
- Rossia palpebrosa Owen, 1834
- Rossia tortugaensis Voss, 1956
Mollusca → Cephalopoda → Sepiida → Sepiolidae → Rossiinae
- Rossiteria
- Rostanga
- Rostellariella
- Rostellariidae
- Rostrilucina
- Rotacharopa
- Rotadiscus
- Roxania
†Roxoa
Animalia → Mollusca → Bivalvia → Myoida
Roybellia Preston, 1913
- Roybellia depressa Preston, 1913
- Roybellia platysoma Sykes, 1900
Mollusca → Gastropoda → Pulmonata → Helicarionoidea → Helicarionidae → Helicarioninae
- Royella
Ru
- Ruapukea
- Rubellatoma
- Rubritrochus
- Rubyspira
- Rugulina
- Runcina
- Runcinacea
- Runcinella
- Runcinida
- Runcinidae
- Runcinoidea
- Ruthia