sciuehs S99 



tail decidedly more than half as long as head and body ; ear 

 conspicuously tufted in winter ; colour reddish, greyish or dark 

 brown above, whitish (never distinctly yellowish) below ; minute 

 anterior upper premolar present ; cross-ridges on upper molars 

 smooth, not tending to become tuberculate ; lower incisors 

 extremely compressed. 



External characters. — Form slender, the head and neck well 

 differentiated from the trunk, the legs rather long, the tail about 

 equal to head and body. Head rounded posteriorly, narrowed in 

 front, the muzzle deep and not much produced (distance from eye 

 to nostril about equal to depth at region half way between) ; ear 

 rather large, just covering eye when laid forward, the width at 

 middle about three-quarters height from crown ; anterior border 

 nearly straight below, somewhat convex above, its lower two- 

 thirds abruptly folded backward, the inner root of this fold lying 

 nearly over meatus ; tip rather abruptly rounded off ; posterior 

 border convex except for a flattened or slightly convex region 

 just below tip, its lower border extending forward as an abruptly 

 angled projection over meatus ; outer surface of ear densely 

 furred at all seasons, the tip conspicuously tufted in winter 

 pelage ; muzzle pad hairy above, a narrow bare area extending 

 between nostrils and across upper lip and sending out a 

 lateral branch under each nostril. Fore feet long and slender 

 with long, freely spreading fingers ; thumb reduced to a mere 

 tubercle with closely appressed nail ; two middle fingers sub-equal 

 and longest, second and fifth sub-equal and about half as long ; 

 palm with five tubercles, the two posterior largest and best 

 defined ; claws long, compressed, strongly curved. Hind foot 

 long, the five toes all well developed and bearing strong claws 

 shorter and less curved than those of fore foot ; inner toe 

 extending about to base of others, outer extending a little beyond 

 middle of fourth ; fourth toe longest, third and second successively 

 a little shorter ; sole densely hairy in winter, partly bare in 

 summer ; four small but evident tubercles at bases of toes. Tail 

 strictly distichous throughout, the hairs at sides and above about 

 30 to 50 mm. in length. Mammae, p 1 — 1, a 2 — 2, i 1 — 1 = 8. 



Colour. — Though the actual colour shows great differences 

 according to phase and season the pattern is constant and 

 characteristic. The head, back, sides and tail are essentially 

 uniform, the tail usually a little darker than back, the sides of 

 body and outer surface of limbs somewhat lighter, the middle of 

 back frequently with more red ; face with an ill-defined pale area 

 on cheeks and muzzle ; ear-tufts usually concolor with sur- 

 rounding parts but sometimes darker or more red ; inner surface 

 of legs and upper surface of feet not so dark as outer surface of 

 legs ; tail with a lighter, grizzled or whitish area along median 

 line below, this sometimes partly or wholly concealed ; white of 

 underparts extending forward to chin or to back of interramial 

 space ; posteriorly the white does not reach base of tail, and 



3 m 2 



