FIELD BOOK OF MAMMALS 



(Osgood) This mouse is so named because it is sometimes 

 found living in or about the brush "nests" of Neotoma 

 fuscipes, a Wood Rat. 

 Southern Parasitic Mouse. — Peromyscus californicus insignis 

 (Rhoads). 

 Resembling typical californicus, but smaller and paler. 

 Upperparts with less rufous, with less black-tipped hairs 

 over mid-dorsal area; pectoral spot frequently absent or 

 usually reduced; rufous at base of tail, underside, much re- 

 duced. Total length, 8.8-9.8 inches; tail vertebrae, 5-5.6 

 inches; hind foot, i.o inch; ear from notch (in dry speci- 

 mens), .8-.83 inch. Found in "Upper and Lower Sonoran 

 Zones of the western valleys and foothills of southwestern 

 Cahfomia and thence south into northern Lower Califor- 

 nia.'' (Osgood) 



Eremicus Group 



Desert Mouse; Western Desert Mouse. — Peromyscus eremi- 

 cus eremiciis (Baird). 

 Size medium, tail much more than half of total length, finely 

 annulated and closely covered with short hairs, terminal 

 tuft scarcely noticeable or completely absent; ears practi- 

 cally naked, good sized, membranous; sole of hind foot 

 naked or nearly so; pelage silky to the touch. Upperparts 

 ochraceous buff with varying (with wear) mixture of dusky, 

 finely sprinkled, over entire dorsal area, no region more 

 noticeably darkened than another; a broad ochraceous buff 

 lateral line; tail above, dusky, below, whitish, not markedly 

 bicolored; underparts clear white or white washed with 

 buffy; buffy pectoral spot occasionally present. Total 

 length, 6.9-8.1 inches; tail vertebras, 3.8-4.3 inches; hind 

 foot, .80-84 inch; ear from notch (in dry specimens), .69- 

 .71 inch. Found in "Lower Sonoran Zone of south- 

 eastern California . . . ; eastward to western Texas, and 

 south to border States of eastern Mexico; northward along 

 the Colorado River, at least to the vicinity of the mouth 

 of the Little Colorado, also extending from the Colorado 

 River along the Virgin Valley to St. George, Utah, and 

 northwestward, crossing southern Nevada, to the Death 

 Valley region of California." (Osgood) 



San Diego Desert Mouse; Dulzura White-footed Mouse.^ — 

 Peromyscus eremicus fraterculus (Miller). 

 Larger than typical eremicus, with longer tail, less white on 

 underparts, and more reddish brown or blackish on upper- 

 parts. Upperparts, in winter, "cinnamon-rufous richly 

 sprinkled with black, which is somewhat concentrated in . 

 middle of back; head with more or less grayish, particularly 

 in postorbital region; underparts creamy white with a 

 small rufous pectoral spot." Or in worn winter pelage, 

 "Ground color cinnamon-rufous, as in winter pelage; tips 

 of hairs not black, but brown or brownish dusky, producing 



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