122 Kelson — A New Pigmy Squirrel. 



Distribution. — Known only from type locality. 



Specific characters. — Pelage soft, thick and woolly; tail slender, flat- 

 tened; upperparts olive brown; breast rusty rufous; rest of underparts 

 mainly grizzled bistre brown; tops of feet and toes washed with rusty. 

 Size about that of S. alfari. 



Color. — Upperparts including sides of body and upper surface of legs 

 uniform olivaceous brown with a dull yellowish shade; sides of head 

 and neck slightly paler and more yellowish; tops of feet and toes washed 

 with rusty reddish; tail dull tawny olive finely washed and tipped with 

 black and thinly edged with pale yellowish tips of hairs; chin and throat 

 dingy rusty: underside of neck and breast rusty rufous shading back 

 into dull grizzled brown; underside of tail dull tawny olive narrowly 

 bordered with black and thinly edged with pale yellowish tips of hairs. 



Measurements. — Measurements of type from dried skin: total length, 

 257; tail vertebrae, 116; hind foot, 37. 



Cranial characters. — Premolars f. Skull longer and proportionately 

 narrower than in S. isthmivs; this character specially marked in rostrum ; 

 interorbital width narrower; brain-case narrower and more highlyarched. 

 lower jaw heavier with angle stronger and more broadly expanded; 

 molar series longer and heavier. The skull of type measures: palatal 

 length, 15.5; interorbital breadth, 14: length of upper molar series, 7. 



Specimt us examined. — One; from type locality. 



General notes. — The soft thick pelage of this species indicates that it 

 is a resident of a comparatively cool and probably humid climate. 



The measurements of the apparently slightly over-stuffed type show 

 that it is about the same size as S. alfari. It may be at once distin- 

 guished from S. isthmivs, S. alfari, and S. similis by the rather pale, al- 

 most grayish, olivaceous color of upperparts, which entirely lack the 

 warm reddish brown suffusion characteristic, in varying degree, of the 

 three species named. 



