42 



MAMMALOGY. 



4. Mus MuscuLUS, Linn. — The Mouse. 

 3Ius musculus, Linn. Syst. Nat. I, p. 83 (1766). 



Like the common rat, the mouse is mentioned as having been 

 noticed at nearly all points visited by the Expedition, and presents 

 another remarkable instance of the adaptation of a species to a great 

 variety of climates and temperatures. We find no specimens in the 

 collection, but the obtaining of such, from various and widely distant 

 localities, especially from those at which this little animal had long 

 since been introduced, would evidently be of high interest, as afford- 

 ing precise demonstration of the real value of climatal and other 

 extraneous influences. 



Mr. Peale mentions this animal as follows : 



" The common mouse seems to keep pace with the progress of 

 civilization, and may be considered a parasite of our race. We saw 

 it in Chili, in Peru, at the Sandwich Islands, New Zealand, and on 

 the Columbia River, in Oregon. In all these localities, as with us in 

 the United States, it frequents the habitations of mankind only, and 

 that always to the exclusion of any small native species of mice, 

 which may have previously partaken of the same abode." 



In addition to the localities given by Mr. Peale, this little animal 

 is mentioned by Dr. Pickering as having been observed at the Feejee 

 Islands, and at San Lorenzo, in Peru. 



2. Genus HESPEROMYS, Waterhouse. 

 1. Hespeeomys leucopus [Rafinesque). — The White-footed Mouse. 



Muscuhis leucopus, Rap. Am. Month. Rev. Oct., 1818, p. 444. 

 Mus syhaticus, FoRSTER, Phil. Trans. London, LXII, p. 880 ? 

 AvD. and Bach. Quad. N. A. pi. 40. 



There are, in the collection of the Expedition, various specimens 

 from Oregon and California, all of which have been referred to this 

 species by Mr. Peale. Though certainly partaking of the general 

 characters of the animal of the Eastern States, we have doubts of 

 their specific identity ; nor can we, with any certainty, regard them 



