108 Fretp Museum or Natura History — Zoé.ocy, Vor. XI. 
parts white, the hairs plumbeous gray at base; under surface of tail 
tawny or grayish according to season. 
In winter: Upper parts tawny brown or pale cinnamon brown. 
Measurements — Total length, about 11 in. (278.2 mm.); tail vertebra, 
1.12 in. (130.5 mm.); hind foot, 1.45 in. (37.6 mm.). 
The habits of the Northern Flying Squirrel are apparently similar 
to its more southern relative (S. volans), with the exception that it is 
more hardy and does not hibernate in winter. Dr. C. Hart Merriam 
says: “The mercury may indicate a temperature many degrees below 
zero, or snow may be falling in quantities sufficient to obstruct the 
vision, without seeming in any way to dishearten this merry adventurer. 
The last rays of the departing sun have scarcely disappeared from the 
western horizon before the sombre shades that mark the approach of 
winter night commence to gather about the snow clad forest. Whether 
bright stars sparkle and shine through a frosty atmosphere, or heavy, 
leaden clouds overhang the scene, makes little difference to the North- 
ern Flying Squirrel. He emerges from his warm nest, takes a hasty 
survey of the surroundings lest some wily owl should lurk hard by, 
glides silently to a neighboring tree, and starts forthwith upon his 
nightly tour in quest of food and sport.” (I. c., p. 206). 
The young number from 3 to 6 and are usually born late in April. 
Specimens examined from Wisconsin and adjoining states: 
Wisconsin — (M. P. M.) Kelly Brook, Oconto Co., 1. (O. C.) Gor- 
don, Douglas Co., 1; Langlade Co., 1r=3. 
Michigan —- Champion, 3. 
Subfamily SCIURINE. 
Genus SCIURUS Linn. 
Sciurus Linneus, Syst. Nat., X ed., I, 1758, p. 63. Type Sciurus 
vulgaris Linn. 
Tail long and thickly haired (bushy); eyes large and ears well 
developed; skull with elongated, pointed (spine-like), postorbital pro- 
cesses; infraorbital foramen small and confined to the lower portion 
of maxillary; toes with claws; front toes 5, four well developed but the 
fifth rudimentary, very small and hardly noticeable; anterior upper 
premolar when present very small. 
Dental formula: I. i. Pm. ais or ——, M, 2-3=22 
IT I 
or 20. 
