RODENTIA-MURINAE-HESPEROMYS LEUCOPUS. 
459 
5,—Tail bicolor, considerably longer than head and body; the end with a long pencil of hairs. 
8. No cheek pouches? Tail three quarters of an inch longer than body. 
Body above yellowish brown. Outside of fore leg to carpus like the 
back. boylii. 
9. With cheek pouches. Tail a quarter of an inch longer than head and 
body, or more. Above dusky cinnamon red; beneath white. Outside 
of fore leg white. Young, dusky. myoides. 
c.—Tail but little longer than the body without the head ; bicolor. 
10. Larger than the preceding. Hind feet long; exceeding .80. Tail shorter. 
Above ashy gray, with a little yellowish brown on the sides. No dusky 
dorsal stripe. Feet pure white. sonoriensis . 
11. Hind feet very short; never exceeding .75, usually under .70. Color 
above dusky brown, with a little yellowish on the lower part of the sides. 
A distinct darker dorsal wash. Feet dusky except the toes. michiganensis. 
B. —Soles perfectly naked. 
12. Tail longer than head and body; scarcely lighter beneath. Size nearly of 
half grown rat. Above sooty brown, passing into fulvous on the lower 
part of the sides...... californicus. 
13. Similar to preceding, except not half the size. Above grayish yellow, 
with a fulvous lateral stripe. eremicus. 
The remaining species of the Hesperomys group are: 
14. Onychomys leucogaster. 
15. Oryzomys palustris. 
HESPEROMYS LEUCOPUS. 
White-footed Mouse—Deer Mouse. 
Mus sylvaticus, var. Erxleben, Syst. An. I, 1775, 390. (Referring to Pennant’s New York variety.) 
Mus sylvaticus, var. noveboracensis, Fischer, Synopsis, 1829, 318. 
Mus agrarius americanus, Kerr, Linnaeus, 1792, 231. (From Pennant.) 
Musculus leucopus, Rafinesque, Am. Month. Mag. Ill, 1818, 446. 
Mus leucopus, Desmarest, Mamm. II, 1822, 307. 
Harlan, F. Am. 1825, 151. 
Griffiths, Cuv. Y, 1827, 233. 
Fischer, Synopsis, 1829, 326. 
Dekay, N. Y. Zool. I, 1842, 82 ; pi. xxiii, f. 1. 
Acd. & Bach. N. Am. Quad. I, 1849, 300 ; pi. xlvi. 
Kennicott, Agric. Rep. U. S. Patent Office, 1856 (1857), 90 ; plate x. 
Hesperomys leucopus, Leconte, Pr. A. N. Sc. Phil. YI, 1852, 413. 
Mus agrarius, Godman, Am. N. H. II, 1828 ? 
Linsley, Am. Jour. Sc. XLII, 1842, 351. 
Mus noveboraeensis, Selys Longschamps, Etudes de Micromammalogie, 1839, 67. 
I Hesperomys maniculatus, Wagner, Wiegmann’s Archiv, 1843, ii, 141.— Ib. 1845, ii, 148.— Ib. Abhand. K. B. 
Akad. der Wissensch. Y, ii, 1848, 316, (or Denkschriften, XXII.) 
Arvicola emmonsii, Dekay, in Emmons’ Rep. Quadrupeds of Mass. 1840, 61. 
American field mouse, Pennant, Syn. 1771, No. 303. 
I Field rat, Pennant, Hist. Quad. 1781, No. 302.— Ib. Arctic Zool. I, 1784, 131. 
I American wandering mouse, Barton, Phila. Med. & Surg. Journal, I, 1805, 31. (Notice of great migratory droves 
on the north side of Lake Erie. May possibly refer to H. myoides.) 
