138 
Q. N. A., ii, 1854, 319 (after Woodhouse).—Baird, M. N. A., 
1857, 464, pl. 8, fig. 1, pl. 52, fig. 5, a, b (Texas and New Mexico); 
U.S. and Mex. Bound. Surv., ii, pt. ii, 1859, 43.—Kennealy, P. 
BRR. Rep... x) 1309 14 pol Sa tiga le 
1855. Hesperomys cognatus, LeConte, Proc. Acad. Nat. Sci., Phila., vii, 
1855, 442 (southern States ; types, Nes. 4708, 4709, Mus. Smiths.). 
—Baird, M. N. A., 1857, 469 (southern States). 
1855. Hesperomys gracilis, LeConte, Proc. Acad. Nat. Sci., Phila., vii, 
: 1855, 442 (Ohio or Michigan, and Wisconsin; types, Nos. —, 
4710, Mus. Smiths.). 
1855. Hesperomys austerus, Baird, Proc. Acad. Nat. Sci., Phila., vii, 1855, 
366 (Wash. Terr.); M. N. A., 1857, 466.—Cooper and Suckley, 
Nat. Hist. Wash. Terr., 1860, 102,_127. 
1855. Hesperomys boylit, Baird, Proc. Acad. Nat. Sci., Phila., vii, 1855, 
830 (Hldorado county, California; type, No 356, Mus. Smiths.) ; 
M.N. A., 1857, 471, pl. 8, f. 3, pl. 52, fig. 3, a-e (California, Ore- © 
gon, and Washington Territory). 
1857. Hesperomys gambeli, Baird, M. N. A., 1857, 464 (Pacific coast, U.5S.). 
—Newberry, P. R. R. Rep., vi, 1857, Zool., 60 —Baird, P. R. R. 
Rep. Cal. Route, 1859, No. 3, 82.—Cooper and Pe Nat. Hist. 
Wash. Terr., 1860, 102, 127. 
1857. Hesperonys Anpath Baird, M. N. A., 1857, 472 (Vermont, based on 
Gapper). 
1860. Mus agrarius, Godman, Am. Nat. Hist., i, 8d ed,, 1850, 316 (also in 
the earlier editions).—Linsley, Am. Journ. Sci, xlii, 1842, 351. 
1374. Hesperomys (Vespertmus) leucopus, Coues, Proc. Acad. Nat. Sci., 
Phila., 1874, 178; Mon. N. A. Rodentia, 1877, 50. 
1875. Hesperomys (Vesperimus) americanus, Coues and Yarrow, Rep. Expl. 
and Surv., W. 100th Merid., 1875, 102. 
Specific Characters.—Average length about 3 25 inches; of tail vertebre 
3 inches; nose to eye, $ inch; length of head 1§ inches; soles, with nails, 
four-fifths of an inch; ears little more than half an inch. Feet and 
under parts of adult snowy white; upper parts light brownish-yellow or 
fawn-color, with a darker stripe along the back. The colors of upper 
parts vary in different specimens and at different seasons. Some sum- 
mer specimens are bluish-gray on the back. The yellow color is clearest 
on the cheeks and along the sides. Upper parts of a young specimen 
were of a uniform blackish ash-color, without any yellow. 
While this animal does not vary in absolute size or relative proportion 
or in character of pelage with latitude, as one might expect, there is 
some color variation, which, Dr. Coues observes, is ‘indescribable 
