1903.] Allen, Mammals from Northern British Columbia. 545 



less plumbeous. Later the amount of white below increases 

 till in half -grown specimens the whole ventral surface is white, 

 with the pelage on the lateral third of the ventral area on 

 either side, more or less plumbeous basally. The color of the 

 upper parts is still dusky gray. When about full-grown the 

 yellowish brown of the adult pelage begins gradually to 

 appear. 



The adults in full pelage are yellowish olivaceous brown 

 above, strongly washed with blackish, through the abundance 

 of long black-tipped hairs intermixed with the general pelage ; 

 below pure white to the base of the hairs, with a tendency to 

 a buffy wash over the middle of the abdominal area. In the 

 worn, faded pelage of the breeding season the upper surface is 

 suffused with pale cinnamon brown. 



Eleven adults measure as follows: 3 males, total length, 

 409 (399-425); tail vertebrae, 171 (167-180); hind foot, 47.3 

 (46-49); ear, 32: 8 breeding females, total length, 370.5 

 (358-380); tail vertebras, 156 (147-165); hind foot, 44.3 (42- 

 46); ear, 30 (28-31). 



Six adult skulls, three males and three females, measure : 

 Total length, 51.5 (49-53); zygomatic breadth, 26.4 (25.4- 

 27.2); interorbital breadth, 5 (4.8-5.2); nasals, 21 (20-22). 



Neotoma cinerea saxamans differs from N. c. drummondi in 

 being paler and of a more yellowish gray brown above, with 

 also the upper parts more strongly varied with blackish. A 

 comparison of the present material with a small series of 

 specimens from the vicinity of Banff, Alberta, shows that the 

 alleged cranial differences mentioned in the description of 

 Neotoma saxamans are of very slight importance, adult and 

 strictly comparable skulls from Banff and Telegraph Creek 

 being indistinguishable as regards the form of the nasals, the 

 maxillary branch of the zygoma, and the more or less openness 

 of the spheno-palatine vacuities. There is apparently a 

 slight average color difference between true drummondi and 

 the more northern bushy-tailed rats, and also in the cranial 

 characters indicated by Osgood, but the Telegraph Creek 

 series presents intermediates, and shows that all of these 

 features are subject to considerable individual variation. 



[October, IQOJ.] 35 



