RODENTIA~—-MURINAE—MUS MUSCULUS. 443 
List of specimens. 
z Measurements. 
<= r= 
2 BS Locality. Whence obtained. Nature of spe- Tip of Nose to— > Length of— Skull— g 
# | ae Pp S 
sy Za cimen. 2 oa 
z | Es : : 
$ = Eye. | Ear. |Occip.| Tail.| 3 | Fore ft. | Hind ft. Length. | Width. 2 
o o | is x 
866 | 1919 | Tarboro’, N.C.........| J. L. Bridger.... .. Skin..... cece |anenes|vesees|ancous | crccerlvaccee|srecnenelecauceies 1.60 77 “rn 
oH le (Ae ecCe & GOeccs vooneccess|ccccce dO. secvecee.. In alcohol..... -80 | 1.50 | 1.90 | 6.15 | 7.92 -70 Leal |ccaneses|ieenelcna -75 
1685 | 563 | Cadereita,N.Leon,Mex.| Lt. D. N. Couch...|....d0.....- veeeleeceee| cevecleecees | seceee|secese| eee ereelseerenec(se ceesslecesereelene . 
QOL jcereee|scccecs dO ..0e cecvceveecleoeees Owsecveces «- SKIN ceceee cece|eccees lenses) eccees[ecssee|sccccn|ssescesslescscnns ser |eeceeees . 
2812 |....../ Niirnberg, Germany....| F'. Stierns......... 200d eccreecees -76 | 1.45 | 1.85 | 5.95 | 6.78 -60 124 [evavcncclecsccces 73 
MUS MUSCULUS, Linn. 
Common Mouse. 
Mus Musculus, Lixn. Syst. Nat. I, 1766, 83. 
Keys. & Bras. Wirb. Europ. 1842, 37. 
Waaner, Suppl. Schreb. III, 1843, 409. 
Aun. & Baca. N, Am. Quad. IT, 1851, 277; pl. xe. 
Burmeister, Thiere Bras, J, 1854, 155. 
GreseEL, Saugt. 1855, 557. 
Sr. Ca.—Tail a little longer than the body. Soles entirely naked. Above grayish brown, finely lined with darker, 
passing insensibly into ashy plumbeous, with a dull reddish tinge on the belly. No distinct line of demarcation. Tail 
dusky all round ; feet ashy brown. 
It is not necessary to enter into any lengthened description of the external form of the com- 
mon house mouse, as its characteristics are much as in the large rats already described. The 
tail is usually a little longer than the body. 
The color of the upper parts is usually of a grayish brown, very finely and intimately lined with 
blackish, sometimes with a tinge of rusty. This passes very insensibly through the rather 
more yellowish sides into the ashy plumbeous of the belly, without any dividing line of any 
kind. There is on the belly a faint wash of a light mud color. The feet are ashy brown; the 
under part of the tail scarcely lighter than the upper. 
While this is perhaps the most constant color, there are occasional variations. Thus, in a 
series from Middleboro’, (864,) the under parts are of quite a pure yellowish white ; the upper 
parts are lighter than as described; the sides are washed faintly with fulvous, and the outside 
of the whitish belly exhibits a brownish tinge, forming a band. The feet are almost pure white ; 
the under surface, however, of the tail scarcely lighter. This same condition is seen in speci- 
mens from Sweden. 
On the other hand, the body is sometimes much darker than usual. One specimen from 
Burlington, Vermont, (1316,) is as dusky as in most skins of the black rat. 
It is not easy to confound the white-footed native mouse of our country with the house mouse 
in any of its phases, as its much larger ears, hairy heels, sharply defined white belly and feet, 
and many other characters, will at once distinguish it. 
The house mouse is originally a native of Europe and Central Asia. At the present time it 
