OREGON FLYING SQUIRREL. 133 



SYNONTME. 



Ptebomys Oregonensis ; Oregon Flying Squirrel, Bach., Jour. Acad, of Nat. Sciences, 

 Phil., vol. viii., pt. i., p. 101. 



DESCRIPTION. 



This species differs from P. sabrinus, in several very striking particu- 

 lars ; the arm which supports the flj'ing membrane is 1 H lines in length, 

 whilst that of the latter is only 9. Thus the smaller of the two has the 

 largest flying membrane. 



The fur of P. sabrinus is much the longest, and is white, whilst that of 

 P. Oregonensis has a yellowish tinge. The hairs on the tail of the for- 

 mer, are only slightly tinged Avith lead-colour, at the roots, . whilst in the 

 latter, that colour e.\tends outwardly, (towards the tips,) for half their 

 length. The different shape of the ear, it being longer and narrower in 

 our present species than in P. sabrinus, is a sufficient distinctive charac- 

 ter. P. Oregonensis differs from the common flying squirrel, {P. volucel- 

 Id) so entirely, that it is hardly necessary to give a particular comparison. 

 Besides being much larger than the latter, and not possessing the beauti- 

 ful downy- white on the belly, it may be distinguished from P. volucella, 

 by the hairs on that species being white to the roots, which is not the 

 case with the Oregonensis. Whiskers, numerous, and very long. 



Fur, deep gray at the base, on the back tipped with yellowish-brown; 

 tail, pale-brown above, dusky toward the extremity ; beneath, brownish- 

 white ; whiskers, chiefly black, grayish at the tips. Hairs covering the 

 flying membrane, mostly black, slightly tipped with pale-brown ; feet, 

 dusky ; around the eyes, blackish ; ears, with minute adpressed brown 

 hairs externally, and brownish-white internally. 



DIMENSIONS. 



Inches. Lines. 



Length from point of nose to root of tail - - - 6 8 



Tail, to point of fur- - - - - - -6 



Height of ear posteriorly .... - 7 



Breadth between the outer edges of the flying mem- 

 brane ......--80 



Longest hind-toe, including nail . - . - 5i 



" fore-toe, " " .... 54 



From heel to point of nail . .... 1 6 J 



From nose to ear .....--1 6 



