Dacrydium knudseni J.A. Allen, 1998
Septifer koeni S. Nomura
Modiolus koneckii (FOSSIL) Dickins, 1963 † Australia, Western Australia, Mullewa
Musculus koreanus K.W. Ockelmann, 1983 Yellow Sea21 mm
Brachidontes kovatschensis (FOSSIL) Krishtofovich, 1981 † Western Kamchatka
Mytilus krishtofovichae (FOSSIL) Devjatilova, 1981 † Western Kamchatka
Musculus krishtofovitchi (FOSSIL) Krishtofovitch, 1964 † Russia, Kamchatka, Tigil'skiy
Leiosolenus kuehnelti (K.H. Kleemann, 1977) Queensland
Modiolus kurilensis F.R. Bernard, 1983 Yellow Sea107 mm
Exosiperna kuroharai T. Habe, 1961 Japan, Tosa Bay
Musculus lacustre H.P.C. Møller
Leiosolenus laevigata (J.R.C. Quoy& J.P. Gaimard, 1835) Galapagos
Musculus laevigatus (J.E. Gray, 1824) Iceland19,1 mm
Promytilus laevis (FOSSIL) Li & Ding, 1982 † China, Jiangxi, Yichun
Arcomytilus laitmairensis (FOSSIL) de Loriol, 1883 † Japan
Perna lamarcki (FOSSIL) G.P. Deshayes † France, Brittany
Idas lamellosus (A.E. Verrill, 1882)
Mytilus lamellosus (FOSSIL) Terquem, 1855 † France, Lorraine, Moselle
Modiolus latecaudatus (FOSSIL) G.B. Pritchard, 1903 †
Musculus lateralis (T. Say, 1822) Florida6 mm
Perna latoconvexa (FOSSIL) R.B. Newton, 1895 †
Solamen leanum (W.H. Dall, 1897) Alaska, Rat Islands
Modiolus leckenbyi (FOSSIL) Morris & Lycett † UK, Yorkshire
Lithophaga lepteces Z.R. Wang, 1997 China, Fujian Province
Lithophaga lessepsiana (L.L. Vaillant, 1865) Red Sea
Adipicola leticiae Signorelli & Crespo, 2017
Jolya letourneuxi J.R. Bourguignat, 1877
Dacrydium leucoguttatum J. van der Linden& R.G. Moolenbeek, 2004 Suriname1,9 mm
Arcuatula leucosticta (E.C. Von Martens, 1897)
Brachidontes levesquei (FOSSIL) G.P. Deshayes, 1858 † France, Paris Basin
Mytilus levesquei (FOSSIL) G.P. Deshayes, 1906 † France, Aquitaine
Modiolus ligeriensis (FOSSIL) d'Orbigny, 1844 † France, Basse-Normandie, Calvados
Lioberus ligneus (L.A. Reeve, 1858) South Africa, Jeffreys Bay16 mm
Benthomodiolus lignocola R.K. Dell, 1987 New Zealand
Inoperna lilliputensis (FOSSIL) Hodges 2000 †