134 Osgood — A Ncic Fhjing Squirrel from Coast of Alasln. 



General charadrrs. — Most similar to Sciurnpterus alpinus ; color much 

 darker throughout; tail, sides of belly, orbital region, forearm, and upper 

 sides of feet much more dusk}'. 



Color. — Type : Upperparts from occiput to base of tail pale russet, be- 

 tween russet and wood brown ; sides of head gray and dusky ; the dusky, 

 which is practically black, forms a line from the base of whiskers to and 

 around the eye and thence becomes plumbeous gray to the posterior base 

 of the ear ; lower cheeks mixed wliitish gray and dusky ; lateral line black 

 witli scarcely any suggestion of brownish tinge ; concealed hairs of under 

 side of lateral line pure creamy white ; upper side of forearm deep blackish 

 brown continuous with and but slightly paler than lateral line; sides of 

 throat grayish lightly mixed with dusky, becoming creamy buff in axillary 

 region; a blackish spot just below lower lip; throat whitish, becoming 

 creamy posteriorly; breast creamy buff faintly tinged with dusky, same 

 color continuous down middle of belly; sides of belly and thence down 

 under side of hind legs pale creamy heavily mixed with dusky producing 

 a huffy gray effect; a small whitish area just in front of anal region ; anal 

 region pale russet mixed with dusky; hairs of upper side of tail liright broc- 

 coli brown subterminally, overlaid and nearly obscured by sooty black; 

 under side of tail slightly more rufescent than upper and less heavily over- 

 laid by sooty ; under side of tail with an indistinct grayish median line ; 

 upper sides of fore and hind feet blackish brown. 



Skull. — Practically as in Si:iuropterus itlpinux. 



Measuremeyits.—'Vype: Total length, 311 ; tail vertebrae, 133; hind foot, 

 42. Average of 6 adults: Total lengtli, 307 (292-311) ; tail vertebrae, 144 

 (133-152) ; hind foot, 41 (40-12).* Skull of type : Basilar length of Hensel, 

 32.3; occipito-nasal length, 41.4; zygomatic breadth, 26.2 ; constriction in 

 front of postorbital processes, 8.3; median length of nasals, 12.8; upper 

 toothrow, 8.2. 



Remarks. — This form needs close comparison only with S. alpinus, which 

 is represented in the Biological Survey Collectjon by at least four typical 

 examples, two from Jasper House, Alberta, practically topotypes, and two 

 from Stuart Lake, B. C. The most convenient cliaracters for distinguishing 

 it are the gray cheeks, the sooty feet, almost pure black lateral line, rela- 

 tively dark forearm, and the heavy mixture of dusky on tlie sides of the 

 belly. *S'. a.fuliginosus, S. yukonensis, and S. oregonensis have the underparts 

 either so much paler or so much more rufescent as to require no comparison. 



* Total length ami tail measurements are the metric equivalents of inches and frac- 

 tions taken by the collector ; hind foot measurements taken from dry specimen. 



