The American bats of the genera Myotis and Pizonyx

Description:

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.

subjects: Pizonyx,  Myotis