1915.] 



MAEMOTA MONAX GROUP. 



33 



MARMOTA MONAX PETRENSIS subsp. nov. 

 British Columbia Woodchuck. 

 (PI. VI, fig. 2.) 



Type from Revelstoke, British Columbia. Adult c? , No. 203532, 

 U. S. Nat. Mus., Biological Survey collection. Collected May 12, 

 1890, by W. Spreadborough; original number, 170. 



Distribution. — Interior ranges of southern British Columbia and 

 adjacent parts of United States, from Barkerville, British Columbia, 

 south to Thompson Pass, Idaho. 



Characters. — Similar to canadensis, but -skull larger and relatively 

 longer. 



Color. — Practically the same as canadensis. 



SJcull. — Similar to that of canadensis, but larger and relatively 

 longer; nasals rather short, projecting but little back of posterior 

 ends of premaxillae; buUae rather small. Compared with rufescens: 

 Smaller with shorter nasals and smaller, rounder bullae. 



Measurements. — ^Adult male (type) : ^ Total length, 540 ; tail verte- 

 brae, 127; hind foot, 76; specimen from Barkerville, British Columbia: 

 460; 106; 72. Adult female (specimen from Barkerville, British 

 Columbia): 505; 125; 68. SJcull: Adult male (type): Condylo-basal 

 length, 86; palatal length, 50.3; postpalatal length, 31.8; length of 

 nasals, 32.5; zygomatic breadth, 57.4; breadth across mastoids, 42; 

 least interorbital breadth, 23; breadth of rostrum, 18.6; maxillary 

 tooth row, 20. Adult female (specimen from Barkerville, British 

 Columbia): Condylo-basal length, 79; palatal length, 46.5; post- 

 palatal length, 29.5; length of nasals, 32.4; zygomatic breadth, 53.2; 

 breadth across mastoids, 36; least interorbital breadth, 19.4; breadth 

 of rostrum, 17.6; maxillary tooth row, 18.8. 



Bemarlcs. — This is a slightly differentiated form of monax, occu- 

 pying an area somewhat segregated from the rest of the species. 

 It is knowa at present from only a few specimens and the limits of 

 its range can not definitely be determined. It probably occurs 

 sparingly throughout the heavily timbered mountain sides of the 

 northern Rocky Mountains in Montana, Idaho, and British Co- 

 lumbia, but whether confined entirely to the west slope or not (as 

 seems probable) has not yet been ascertained. This subspecies has 

 no direct connection with monax or rufescens, its range being separated 

 from theirs by an extensive area of plains, but it undoubtedly inter- 

 grades with ocJiracea on the north and possibly with canadensis 

 through some of the passes of the mountains in southern British 

 Columbia. 



Specimens examined. — Total number, 6, as follows: 



British. Columbia: Barkerville, 2; Glacier, 2; Revelstoke, 1. 

 Idaho: Thompson Pass, 1. 



69168°— 15 — 3 



» From dry skin. 



