Radiacmea, Genus – synonym of Acmaea, Genus
Radiata, Genus – synonym of Pusillina, Genus
Rasbittium, Genus – synonym of Bittium, Genus
Retiarcularia, Genus – synonym of Nassarius, Genus
Reticunassa, Genus – synonym of Nassarius, Genus
Retusophiline, Genus – synonym of Philine, Genus
Rhizorus, Genus – synonym of Volvulella, Genus
Rhomboides, Genus – synonym of Hiatella, Genus
Rissomangelia, Genus – synonym of Mangelia, Genus
Rissostomia, Genus – synonym of Rissoa, Genus
Robaia, Genus – synonym of Nuculana, Genus
Rosenia, Genus – synonym of Pelseneeria, Genus
Rostrisepta, Genus – synonym of Propilidium, Genus
Roxellaria, Genus – synonym of Petricola, Genus
Rudicardium, Genus – synonym of Acanthocardia, Genus
Ruditapes, Genus – synonym of Tapes, Genus
Rugocythara, Genus – synonym of Mangelia, Genus
Rupellaria, Genus – synonym of Petricola, Genus
Ruperella, Genus – synonym of Petricola, Genus
Rupicella, Genus – synonym of Thracia, Genus
Rupicilla, Genus – synonym of Thracia, Genus
Rupicola, Genus – synonym of Thracia, Genus
Ryenella, Genus – synonym of Modiolarca, Genus