1 6 Bulletin American Museum of Natural History. [Vol. XII, 



P. t. subarcticus differs from P. t. arcticus in the general effect 

 of the color of the upper parts being dusky brown instead of 

 blackish brown, in the much more heavily clothed tail, and 

 smaller size (in the average of specimens referable to this form). 

 It differs from P. t. nebrascensis in being dusky brown above 

 instead of cinnamon brown. 



I refer to this form not only the Black Hills (South Dakota) 

 specimens formerly referred by me (/. c.) to arcticus, but also a 

 series of six specimens collected at Osier, Saskatchewan (received 

 in exchange from Mr. O. Bangs). The latter agree exactly in 

 color with the Montana series of subarcticus, but not at all well 

 with the series from the Upper Liard River region in the Stone 

 collection (see above, p. 8), which are fresh, unfaded specimens 

 of true arcticus. The Black Hills specimens are not all typical, 

 some of them decidedly approaching P. t. nebrascensis, while 

 others are quite like the Montana and Saskatchewan examples. To 

 subarcticus must also be referred the specimens from Colorado, 

 Wyoming, and Utah, formerly placed by me under arcticus (I.e.). 



Sciurus^chapmani, sp. nov. 



Sciurus cestuans hoffmanni ALLEN & CHAPMAN, Bull. Am. Mus. Nat. Hist. 

 V, 1893, 209; ibid. IX, 1897, 17. (Not of Peters, 1864.) 



Similar to Sciurus hoffmanni (Peters) but smaller and differing in color and 

 in cranial characters. 



Above nearly uniform dull yellowish brown finely varied with black, the 

 hairs individually plumbeous at base, and annulated on the apical half with pale 

 fulvous and black, with the tip usually black ; the sides of the body are uniform 

 with the back, there being no tendency to a darker median band. Below red- 

 dish fulvous, varying in different individuals from pale orange to deep reddish 

 orange, lighter on chin and throat. Outer surface of limbs and feet like the 

 dorsal surface ; inner surface of same like the ventral surface. Tail dark 

 brown above, the hairs tipped and the edges of the tail fringed broadly with 

 dark chestnut red ; the hairs individually are ringed with two bands of pale 

 fulvous alternating with two of black, besides the red tipping, the two outer 

 bands being broader than the two inner ; these bands are hidden on the dorsal 

 aspect by the red tips of the hairs, but below are plainly visible. 



Total length (collector's measurements) of type, to end of tail vertebrae, 370 

 mm. ; tail vertebrae, 162 ; hind foot (with claws), 46 ; ear, 19. A series of 7 

 adults (233,5 2 ? ) measure as follows : total length, 376 (367-390) ; tail 

 vertebrae, 174 (162-192) ; hind foot, 46 (44-48) ; ear, 19 (18-20). 



Skull, total length, 49 ; width behind postorbital processes, 17.6 (average of 

 5 adult skulls). 



