1897.] NATURAL SCIENCES OF PHILADELPHIA. 325 



Geographic distribution. — Lower elevations of the Pacific Slope, 

 from southern Alaska to northern California, intergrading at 

 higher elevations with fuliginosus and southwardly toward a lighter 

 colored race more closely allied to calif ornicus. 



Habitat. — Coniferous and deciduous forests. 



General characters. — Size intermediate between alpiims and 

 volans ; tail long and slender; colors darkest of the American fly- 

 ing squirrels. 



Color (winter pelage). — Above, including body, crown of head, 

 hips and shoulders Mars-brown with a russet shade and tinged with 

 clay color, the whole being darkened by numerous black-tipped 

 hairs. Upper surfaces of feet, hams, shoulders, flying membrane, 

 ears and tail more or less shaded with seal-brown to slate-black ; in 

 darkest individuals from Sumas, B. C, these parts are dark clove- 

 brown to black. In the type the black has faded to dark Isabella 

 color, and the brown to light russet, the darker terminal part of the 

 tail being slaty russet. In British Columbia and Alaska specimens 

 of oregonensis the upper tail and feet are in marked contrast with 

 the colors of the back and rump, becoming slaty at the base of the 

 tail, and in darkest specimens this becomes dull black over the ter- 

 minal third of the tail, the hairs of the upper base of the tail being 

 more or less mixed with dark wood-brown or broccoli brown. In 

 the type the contrast between tail and body colors is less marked. 

 Another color peculiarity of oregonensis is the slight difference in 

 shade of upper and lower caudal pelages and the contrast between 

 the lower tail and lower body colors. In all the other American 

 forms the tail colors agree closely with those of the corresponding 

 surface of body. 



Lower surface of body, from base of neck to vent, Isabella-color, 

 tinged with rusty on thighs, breast and flying membrane, and more 

 or less darkened by the exposed slate-gray bases of hairs, this color 

 reaching more than half way to the hair tips. Lower surface of 

 fore legs, a spot on chin and a narrow median area from breast to vent, 

 whitish. Region around *mouth and eyes and nasal pad blackish. 

 Sides of face and across rostrum light slate-gray. 



Dimensions (of type, fide Bachman, taken from skin). — Total 

 length, 302 millimeters; tail vertebrae, 132; hind foot, 39; ear, 

 from crown, 15; carpal fascia, 23.5. Average dimensions of four 

 adults, two from Oregon, two from Sumas, B. C, in above order: 

 288, 135, 39, 1 7, 23. Skull : average of three adults— total length, 39 ; 



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