This catalogue includes all type-specimens of mammals known to be in the U.S. National Museum on July 1, 1908, embracing a general collection in the Division of Mammals and a large collection of American mammals made by the Bureau of Biological Survey of the U.S. Department of Agriculture, which is kept in a special hall of the Museum.

This volume is a second catalog of the type specimens of recent mammals in the United States National Museum, including those now in the collections made by the Fish and Wildlife Service, United States Deaprtment of Interior. The present list records all the type specimens in both collections at the end of 1940, a total of 2,824, of which 1,409 are new additions since the publication of the first type list of 1909.

This catalogue includes all type-specimens of mammals known to be in the U.S. National Museum on July 1, 1908, embracing a general collection in the Division of Mammals and a large collection of American mammals made by the Bureau of Biological Survey of the U.S. Department of Agriculture, which is kept in a special hall of the Museum.