Since the late Oldfield Thomas defined the four subgenera and described three species in 1910, only three additional forms of Pseudomys have been recorded. The inference is either that but few races of this interesting genus remain undiscovered, or that individual forms have been accorded far too extensive ranges in the past. For example, two distinct species from Central Australia relegated to coastal forms by Waite, are shown herein to belong to entirely different subgenera and are described as new.
There could be no more definite proof of the value of field work than that a review of the Australian Museum Pseudomys, comprising the "old collection", and recent material gained under the inadequate collecting resources now available, revealed interesting and new forms only part of which can be dealt with here.
During 1931 Mr. E. F. Boehm, of Sutherlands, South Australia, submitted young specimens for identification and exchange. Owing to difficulty in sorting out the affinities of immature material, the Trustees secured adults from Mr. Boehm, who accorded permission to describe the form. I am indebted to Mr. A. S. Le Souef for the opportunity to describe specimens from Western Australia; also to Mr. T. Hodge-Smith, Mineralogist and Petrologist to the Museum, who, while on an expedition to the interior in 1930, secured specimens of a form not reported since 1896.