138 



Q. N. A., iii, 1854, 319 (after Woodhouse).— Baird, M. N. A., 



1857, 464, pi. 8, fig. 1, pi. 52, fig. 6, a, b (Texas and New Mexico) ; 



U. S. and Mex. Bound. Surv., ii, pt. ii, 1859, 43. — Kennealy, P. 



R. R. Rep., X, 1859, 14, pi. 8, fig. 1. 

 1855. Hesperomys cognatus, LeConte, Proc. Acad. Nat. Sci., Phila., vii, 



1855, 442 (southern States ; types, Nos. 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 austeriis, 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 boylii, Baird, Proc. Acad. Nat. Sci., Phila., vii, 1855, 



335 (Eldorado county, California ; type. No 356, Mus. Smiths.); 



M. N. A., 1857, 471, pi. 8, f 3, pi. 52, fig. 3, a-e (California, Ore- 

 gon, and Washington Territory). 

 1857. Hesperomys gamheli, Baird, M. N. A., 1857, 464 (Pacific coast, U. S.). 



—Newberry, P. R. R. Rep., vi, 1857, ZooL, 60— Baird, P. R. R. 



Rep. Cal. Route, 1859, No. 3, 82.— Cooper and Suckley, Nat. Hist. 



Wash. Terr., 1860, 102, 127. 

 1857. Hesperomys myoides, Baird, M. N. A., 1857, 472 (Vermont, based oa 



Gapper). 

 1860. Mus agrarius, Godman, Am. Nat. Hist., i, 3d ed„ 1860, 316 (also in 



the earlier editions). — Linsley, Am. Journ. Sci , xlii, 1842, 351. 



1874. Hesperomys (Vesperimus) leucopus, Coaes, 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 vertebrae 

 3 inches; nose to eye, J 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 



