164 Bangs The &<j_v.irrch of Enxtern Xortli 



Geographic distribution. Limits of range unknown, probably the higher 

 southern Alleghanies. 



General characters. Size smallest of the eastern flying squirrels ; similar 

 in general appearance to S. sabrinus, but darker in color ; soles naked in 

 summer. 



Color. The type (in summer, beginning to change to winter pelage) : 

 upper parts hair brown, shading in places toward Isabella color; ears and 

 upper surface of tail, feet, and hands sooty ; cheeks dark gray ; a black 

 orbital ring; under parts grayish white, the hairs somewhat darker at 

 base ; under surface of tail drab, shading to sooty ; soles and palms naked ; 

 the skin black. 



Cranial characters. Skull very small, similar to that 

 of S. sabrinus in respect to the flat audital bulise and 

 large teeth, but differing in having the foramen ovale 

 transversely oval instead of round. The peculiar 

 pug-nosed effect given by the turned-up ends of the 

 FIG. 29. Rostrum of nasals is even more exaggerated than in sabrinus. 

 Sduropterus situs. g ize of the type gkull . basilar length, 25.8 ; occipito- 

 nasal length, 31; zygomatic breadth, 19; greatest 

 height of cranium above palate, 12.2 ; greatest length 

 of single half of mandible, 18.6. 



Size. The type: total length, 214; tail vertebrae, 

 92 ; hind foot, 28. 

 FIG. 30. -Rostrum of General remarks. Sduropterus silus is known at 



Sciuropterusvolans. pregent only by the type> aU my efforts to get ad _ 



ditional specimens having so far failed. Lieut. Wirt Robinson spent 

 part of the summer of 1896 at White Sulphur Springs, W. Ya,, and 

 kindly offered to get me flying squirrels. He succeeded in taking but 

 one, a perfectly typical example of S. volans. It was taken at an altitude 

 of about 1,200 feet lower than the type of *!?. silus. It is probable that 

 the ranges of the two species overlap. 



Sduropterus silus bears no very close relationship to S. volans, although 

 it is even smaller than that species. Its affinities lie with S. sabrinus, of 

 which it is probably the Alleghany Mountain representative. It is, how 

 ever, so very much smaller than that species and differs from it so much 

 in other respects that I have accorded it specific rank. 



Specimen examined. The type. 



Sduropterus volans volans (Linn.). Southern Flying Squirrel. 



1758. Mus volans Linn., Syst. Nat., ed. 10, I, 1758, p. 63. 



1758. Sciurus volans Linn., Syst. Nat., ed. 10, I, 1758, p. 64 (in part). 



1788. Sciurus volucella Pallas, Nov. Spec. Glires, 1788, p. 351. 



1818. Pterornys volucella Desmarest, Nouv. Diet, d'Hist. Nat., XXVI F, 

 1818, p. 406; And. and Bach., Quad. N. Am., I, 1849, p. 216, pi. 

 XXVIII; Baird, Mamm. N. Am., 1857, p. 286. 



1828. Sduropterus volucella Geoffrey, Diet. Class. d'Hist. Nat., XIV, 1828, 

 p. 132. 



1874. Sduropterus volucella var. volncella Allen, Proc. Boston Soc. Nat. 

 Hist, XVI, 1874, p. 189 ; Monog. N. Am. Sciuridse, 1877, p. 655. 



1890. Sduropterus volans Jordan, Man. Vertebrates, 1890, p. 324, foot 

 note. 



