http://www.bucknell.edu/msw3/
Mammal Species of the World, 3rd edition (MSW3) is a database of mammalian taxonomy. It is hoped that this database on the World Wide Web can be used as a convenient on-line reference for identifying or verifying recognized scientific names and for taxonomic research. The names are organized in a hierarchy that includes Order, Suborder, Family, Subfamily, Genus, Species and Subspecies.