No. 15, NOBTH AMERICAN FAUNA. August, 1899. 



REVISION OF THE JUMPING MICE OF THE GENUS ZAPUS. 



By EDWARD A. PREBLE. 

 INTRODUCTION. 



History and material. The Jumping Mice of North America early 

 attracted the attention of naturalists, but their true status and rela- 

 tionships long remained in obscurity. The first reference to any of the 

 species seems to have been made by Thomas Pennant, in the latter part 

 of the last century, who mentioned the animal under the name of the 

 1 Long-legged Mouse of Hudson's Bay.' In 1780 Zimmermaun, basiug 

 his description on that of Pennant, and supposing the animal to be con- 

 generic with the jerboas of the Old World, named it Dipus hudsonius. 

 Subsequent authors, recognizing the inapplicability of Dipus, referred 

 the species successively to Gerbillus, Meriones, and Jaculm, until finally 

 Dr. Elliott Coues, in 1875, after showing that all the generic names 

 previously used were untenable, proposed Zapus. 



Previous to 1857 a number of specific names were used for members 

 of this genus (see pp. 10-13), but were applied mainly to specimens from 

 the eastern United States and Canada. Suffice it to say that Baird, 

 in 1857, and Coues, in 1877, recognized but one species, having a range 

 nearly coincident with the present geographic distribution of the genus 

 in North America. This resulted mainly from two causes poor qual- 

 ity of existing material and the prevailing tendency of the times to 

 lump distinct species having a superficial resemblance to one another. 

 The material consisted mainly of poorly preserved alcoholic speci- 

 mens, or skins badly made (in most cases with the skulls inside), 

 and without satisfactory measurements. The characters distinguishing 

 the species, therefore, were not apparent or were considered as being 

 due merely to individual variation. In failing to examine skulls, both 

 Baird and Coues referred specimens of the animal since described as 



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