The Freshwater Mussels (Unionoida) of the World (and other less consequential bivalves)
FM(U)otW(aolcb) is the web version of the MUSSEL Project Database. Follow the links to browse the data or use the custom Google search field. Either way, you win!
Search the database pages:
nominal species Margaritifera perdahurica Yokoyama, 1932
Yokoyama, 1932, Jour. Fac. Sci., Univ. Tokyo 3(6): 244, pt. 6, pl. 4, fig. 2.
