The purpose of this application, under Articles 23.9.3 and 81.1 of the Code, is to conserve the current usage of the specific name of the northeast Pacific Ocean marine mussel Mytilus californianus Conrad, 1837, the identity of which has never been questioned. After examining the type specimens of Mytilus zonarius Lamarck, 1819 and Mytilus canalis Lamarck, 1819, Huber (2010) concluded that they were M. californianus and used the former as its valid name. Neither Mytilus zonarius nor M. canalis have been used as the valid name of Mytilus californianus between 1819 and 2010. The name Mytilus californianus has been used as the valid name of this species in thousands of publications between 1837 and 2020. It is proposed to conserve the name Mytilus californianus Conrad, 1837 by reversal of precedence with the names Mytilus zonarius Lamarck, 1819 and Mytilus canalis Lamarck, 1819.