322 University of California Publications in Zoology [Vol. 12 



auricular spots larger and whiter, top of head and rump grayer in 

 tone, and tail hairs distinctly tipped with gray. 



Description. — Adidt summer, or post-breeding, pelage (from type) : 

 Under parts from chin to base of tail, white, with creamy tinge mid- 

 ventrally; insides of thighs and arms, light ochraceous-buff ; upper 

 surface of feet, dull ochraceous-tawny ; sides and general suffusion 

 over back, bright cinnamon-rufous, approaching apricot-orange in tone 

 along the lower sides ; narrow black median stripe from between ears 

 to rump, fading out near base of tail; rest of dorsal stripes much 

 shorter, not extending forward of shoulders ; median dorsal stripe bor- 

 dered on each side by a gray line, this much obscured with ferrugin- 

 ous; outwardly of gray stripe on each side is a black stripe dulled 

 by intermixture of ferruginous hairs; succeeding this outwardly is a 

 conspicuous clear ashy-white stripe on each side, and outwardly to 

 this a much shorter stripe of dusky along the upper edge of the 

 otherwise bright cinnamon-rufous side. There are thus three black 

 stripes and four light stripes, the outermost pair of which is con- 

 spicuously whitish (much more clearly so than in hindsi). Rump and 

 flanks, grizzled Brussels brown; tail beneath, bright Sanford's brown, 

 outwardly margined with black and ashy white; tail dorsally black, 

 with a little of the ochraceous-orange bases of the hairs showing 

 through, and grizzled with the ashy-white hair tippings. Ears lightly 

 lined inwardly with hazel hairs; front half of outer surface of ear, 

 dull cinnamon-rufous, posterior half light mouse gray ; triangular spot 

 behind each ear, clear white, slightly tinged with ashy, but much more 

 conspicuous than in hindsi; top of head grizzled grayish brown; head 

 stripes more brightly contrasted with each other than in either hindsi 

 oi- ochrogenys; stripes from nose to base of ear, above and below eye, 

 white, slightly dulled with black and ferruginous hairs; a dusky stripe 

 above each whitish supra-ocular stripe, becoming blacker anteriorly 

 and meeting its fellow on tip of nose; a black stripe, dulled by fer- 

 ruginous, from eye to base of ear; a similarly colored but narrower 

 stripe beneath the whitish subocular stripe ; a dull brownish suffusion 

 between eye and snout; whiskers black. Measurements of type: total 

 length, 260 mm.; tail vertebrae, 112; hind foot, 36; ear from crown, 

 17. Thirty adult specimens of sonomae average, as measured by field 

 collectors: total length, 251 mm.; tail vertebrae, 113; ratio tail to 

 body, 82 per cent. Eighteen adults of hindsi average: total length, 

 232 mm. ; tail vertebrae. 102; ratio tail to body, 78 per cent. Cranial 

 differences are not apparent. Breeding I worn winter) pelage : pattern 



