FIELD BOOK OF MAMMALS 



the crotches of the limbs. Individuals use the same tree 

 season after season if unmolested. 



The young number two to four, the usual number bemg 

 three, and there is not much evidence to indicate definitely 

 that more than one litter is raised a season. The young are 

 born in March or April. 



Subfamily Pteromyinae 

 Genus Glaucomys' 



Dentition: Incisors, A; Canines, g; Premolars, f ; Molars, | = 22. 



Flying SquirreL— Glaucomys volans 



and related forms 



General Description.— An arboreal Squirrel of small to me- 

 dium size almost entirely noctural in habit, with large eyes, 

 very soft pelage, and broad, lateral folds of skin extendmg 



FiG. 55. Flying Squirrel 



:rom wrists to ankles which enclose a slender, cartilaginous 

 process or stiffening rod arising from the wrist; tail fiat and 

 broad, tip rounded. Plate XXV. 



Color. — Sexes colored alike. ^ 



Upperparts.— Varying with the individual, from drab to 

 pinkish cinnamon, washed with pinkish buff along sides; fur 



1 For a full review of the American Flying Squirrels see Arthur " 

 Howell. North American Fauna, No. 44, iQiS. 



2 Very difficult to convey in a short, written description the colo^ 

 differences between these forms. Often the individual range of va, 

 ation within a subspecies covers the same shades of color as commonly 

 characterize other subspecies. 



260 



