Gerrit S. Miller

The object of the present list is to summarize the results of taxonomic studies of North American recent mammals up to January 1, 1953, and to indicate the forms represented in the United States National Museum. North America as here understood includes the entire continent from Panama northward, Greenland, the Greater Antilles, and the Lesser Antilles south to Grenada. At least 263,214 specimens, including 1871 types, comprise the collection of North American Recent Mammals in the United States National Museum.

The bats of the genus Myotis, though small and inconspicuous mammals, present many features of unusual interest from the point of view of systematic zoology. At nearly every point in its excessively wide range the genus is represented by several species often puzzlingly alike in superficial appearance though readily distinguishable from each other when the true differential characters are once recognized.

The North American recent mammals in the United States National Museum number about 166,000 specimens, including 1,435 types. More than three-fourths of this material is in the Biological Survey collection, United States Department of Agriculture, the remainder, including the seals, sirenians, ceataceans, and all of the older, more historic specimens, is in the Museum proper. The material derived from these two sources furnishes so complete a representation of the mammals of North America that, of the 2,554 forms now recognized, only 171 are not included.

This classification of the families and genera of bats, primarily based on skeletal and dental characters, is chiefly the result of Miller'study of the collections in the United States National Museum. All questions of nomenclature have been decided in accordance with the Code of Nomenclature of the American Ornithologists' Union, pending final adoption of an international code.