16 



This animal is said to be unable to swim, and that it is often 

 drowned in its burrows, when they are inundated by the sudden rise 

 of the prairie streams. 1 Whether or not large rivers form impassable 

 barriers to it, it seems to be well substantiated that while this animal 

 occurs on the Iowa side of the Mississippi and in central Illinois, or 

 throughout that part of the latter State south and east of the Illinois 

 river, it does not exist in that portion situated between the Illinois 

 and the Mississippi. Mr. Kennicott refers to his having heard this 

 reported, but he was unable to vouch for the truthfulness of the ac- 

 count. When in this section of Illinois, however, I was repeatedly 

 informed by competent and trustworthy observers who had resided in 

 this part of the State since its first settlement, and who had traversed 

 it extensively, that the pocket gopher did not exist in that portion of 

 Illinois between these rivers . This fact seems the more strange when 

 we remember that the gopher is common in portions of Wisconsin, be- 

 ing in fact very numerous in Winnebago and Fond du Lac counties, 

 as I have myself ascertained. 



The Perognathus fasciatus may well be expected to occur in south- 

 western Iowa, since it is well known to exist in northeastern Kansas, 

 not many miles from the Iowa border. 



MURID^. 



40. Jaculus hudsonius Baird. (Jumping Mouse.) 

 Doubtless not uncommon, since it is numerous in neighboring por- 

 tions of Wisconsin and Illinois. 



41. Hesperomys leucopus Wagner. (White-footed Mouse.) 

 A species I take to be this was not uncommon. From the locality 



it may be what has been recognized by Professor Baird as the H. 

 sonoriensis of Le Conte, 2 described by the latter gentleman from a 

 specimen from Sonora. Specimens are referred to it by Professor 

 Baird from Fort Union and other localities in northwestern Dacotah, 

 and from various intermediate points southward to Texas and New 

 Mexico ; the H. leucopus of Richardson from the Saskatchawan being 

 also referred to it, it is thus recognized as having a considerable 

 range in latitude. The western limit of H. leucopus is given by Pro- 

 fessor Baird as the Mississippi. As my specimens are not appreciably 

 different from H. leucopus from Massachusetts, one is left to two 

 alternatives ; either that of regarding the H. leucopus as ranging 

 westward across the State of Iowa to the Missouri, or of considering 



i K. Kennicott. Patent Office Rep., Agriculture, 1857, p. 76. 

 Mam. N. Amer., p. 474. 



