Mytilarca iniqua (FOSSIL) Isberg, 1934 †
Ambonychia intermedia (FOSSIL) F.B. Meek & A.H. Worthen †,
Ambonychinia intermedia (FOSSIL) Isberg, 1934 †
Allonychia jamesi (FOSSIL) (F.B. Meek, 1872 †)
Ambonychinia kallholniensis (FOSSIL) Isberg, 1934 †
Ambonychiopsis kallholniensis (FOSSIL) Isberg, 1934 †
Mytilarca kallholniensis (FOSSIL) Isberg, 1934 †
Mytilarca knappi (FOSSIL) J.W. Hall, 1884 †
Ambonychinia kullsbergensis (FOSSIL) Isberg, 1934 †
Mytilarca kullsbergensis (FOSSIL) Isberg, 1934 †
Cleionychia lamellosa (FOSSIL) (R.P. Whitfield, 1882 †)
Mytilarca lata (FOSSIL) J.W. Hall, 1883 †
Claudeonychia laticostata (FOSSIL) (Ulrich, 1895 †)
Amphicoelia leidyi (FOSSIL) J.W. Hall, 1865 †
Mytilarca leptaenarum (FOSSIL) Isberg, 1934 †
Ambonychinia levis (FOSSIL) Isberg, 1934 †
Paramytilarca levis (FOSSIL) Isberg, 1934 †
Mytilarca lineatus (FOSSIL) Reed 1944 †
Ambonychinia magna (FOSSIL) Isberg, 1934 †
Mytilarca mareki (FOSSIL) Kríž & Steinová, 2009 †
Cleionychia marginalis (FOSSIL) W.J. Raymond, 1905 †
Mytilarca marylandica (FOSSIL) Ohern in Ohern& C.J. Maynard, 1913 †
Ambonychiopsis mclearni (FOSSIL) Northrop, 1939 †
Ambonychinia megumbona (FOSSIL) Isberg, 1934 †
Cleionychia miseneri (FOSSIL) Ulrich, 1893 †
Cleionychia montrealensis (FOSSIL) (Billings, 1859 †)
Mytilarca mytiliformis (FOSSIL) (J.W. Hall, 1852 †)
Cleionychia mytiloides (FOSSIL) (J.W. Hall, 1847 †)
Claudeonychia notabilis (FOSSIL) (Ulrich, 1895 †)
Ambonychia obesa (FOSSIL) Ulrich, 1895 †
Mytilarca obliqua (FOSSIL) Weller, 1903 †
Paramytilarca oblonga (FOSSIL) Isberg, 1934 †
Byssopteria occidentalis (FOSSIL) Fenton & Fenton, 1924 †
Ambonychia orbicularis (FOSSIL) (E. Emmons, 1842 †)
Mytilarca orsae (FOSSIL) Isberg, 1934 †