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Tilt: AM EMC AX XATURALTST [Vol. XLIII 



familiarly known as wood mice, doer mice, vesper mice (in allu- 

 sion to their semi-nocturnal habits), or white-footed mice (from 

 the fact that nearly all have white feet). They are at home in 

 all sorts of environments, from moist woodlands to the open, 

 semi-arid deserts, and vary in size from an animal smaller than 

 the common house mouse to species nearly the size of a two 

 thirds grown brown rat. The extremes of the group differ 

 widely, not only in general size but in the size of the ears, the 

 relative length of the tail, in coloration, and in dental and cranial 

 characters. They are all subject, each after his kind, to a wide 

 range of color variation, dependent upon age, season and abra- 

 sion of the pelage. They are also a plastic group, responding 

 quickly to changes in the environment, so that quite diverse and 

 irmiiraphically widely separated forms are often connected by 

 an unbroken chain of intergrades, which renders the satisfactory 

 allocation of closely allied forms extremely difficult, owing 

 largely to the complications that have arisen from the bestowal 

 of names upon what prove to have been intermediate forms. 

 The naming of species and subspecies has been, in most instances, 

 necessarily haphazard, since for a quarter of a century there has 

 been no attempt to coordinate the work of the numerous describ- 

 es who have raised the number of named forms from about a 

 score in 1885 to fully '200 in 1908. 



For several years Mr. Wilfred H. Osgood 1 has been at work 

 upon a monographic revision of the genus, based upon a critical 

 study of over 27,000 specimens, including the available material 

 in all the principal collections, both private and public, in this 

 country, supplemented by the examination of types and other 

 important material in the museums of Europe. ' ' This material, ' ' 

 says the author, "includes all the types, both of valid forms and 

 synonyms. In almost all cases in which no types exist, good 

 series of topotypes, or specimens from near the type localities, 

 have been available." The greater part of the specimens ex- 

 amined were collected by the Biological Survey, under the direc- 

 tion of Dr. C. Hart Merriam, with the special purpose of bring- 

 ing together the material necessary for the proper monographic 

 revision of the group. The results of Mr. Osgood's studies are 



»"A Bevision of the Mice of the American Genus Peromyscus. " By 

 Wilfred H. Osgood, Assistant, Biological Survey. Prepared under the direc- 

 tion of C. Hart Merriam, Chief of Biological Survey. North American 

 Fauna, No. 28. Published April 17, 1909. 8vo, pp. 1-285, pi. i-viii, colored 

 map, and 12 text figures (small distribution maps). 



