I02 Field Museum of Natural History — Zoology, Vol. XI. 



Subfamily PTEROMYINiE. 



Genus SCIUROPTERUS Cuvier. 



Flying Squirrels. 



Sciuropterus F. Cuvier, Dents du Mammiferes, 1825, p. 255. Type 



Sciurus volans Linn. 



Tail flat, thickly haired laterally; legs and body connected by 

 loose skin which, when extended, becomes wing-Hke, enabling the 

 animal to sail on a downward slant for a considerable distance; fur 

 very soft and thick; occipital region depressed; rostrum short; infra- 

 orbital foramen small and confined to lower part of maxillary; post- 

 orbital process narrow and pointed (spine like); audital bullae large; 

 eyes large. Two species occur within our limits. 



Dental formula: I. ? C. ^ Pm. j M. ^^ — ^=22. 



. i-i 0-0 i-i 3-3 



KEY TO OUR SPECIES. 



Total length usually less than 10 inches; fur of belly white to base. 



Southern Flying Squirrel. Sciuropterus volans, p. 102. 

 Total length usually more than 10 inches; fur of belly dark at base. 



Northern Flying Squirrel. Sciuropterus sahrinus, p. 106. 



Subgenus GLAUCOMYS Thomas. 



Sciuropterus volans (Linn.). 



Flying Squirrel. Southern Flying Squirrel. 



\Mus] volans Linn., Syst. Nat., X ed, I, 1758, p. 63. 



Sciuropterus volans Jordan, Man. Vert. Anim., 1890, p. 324. Garman, Bull. Essex 

 Inst., XXVI, 1894, p. 5 (Kentucky). Evermann & Butler, Proc. Ind. Acad. 

 Sci., 1893 (1894), p. 131 (Indiana). Hahn, Proc. U. S. Nat. Mus., XXXII, 

 . 1907, p. 459 (Illinois). /&., Ann. Rept. Dept. Geol. & Nat. Resources Ind., 1908 

 (1909), p. 485 (Indiana). Osborn, Proc. Iowa Acad. Sci., I, 1887-89 (1890), 

 p. 43 (Iowa). Rhoads, Proc. Acad. Nat. Sci. Phila., 1896 (1897), p. 197 (Ten- 

 nessee). Snyder, The Oregon Naturalist, IV, 1897, p. 9 (Wisconsin). 76., 

 Bull. Wis. Nat. Hist. Soc, II, 1902, p. 118 (Dodge Co., Wisconsin). Jackson, 

 Proc. Biol. Soc. Wash., XX, 1907, p. 70 (Missouri). Ih., Bull. Wis. Nat. Hist. 

 Soc, VI, 1908, p. 19 (Wisconsin). Wood, Bull. 111. State Lab. Nat. Hist., 

 VIII, 1910, p. 533 (Champaign Co., Illinois). 



Sciuropterus volans volans Bangs, Proc. Biol. Soc. Wash., X, 1896, p. 162 (Missouri, 

 Indiana, etc.). 



Sciuropterus volucella Herrick, Geol. & Nat. Hist. Surv. Minn., Bull. No. 7, 1892, 

 p. 159 (Minnesota). 



