105 
by Hamilton M. Laing; original No. 555, Allotype : Female adult, skin 
and skull, No. 7953, taken at same place and date; original No. 556. 
Geographic Distribution. Known only from Similkameen valley, 
eastern slope of Cascade range in British Columbia, from the dry Transition 
zone country near Princeton at 2,400 feet altitude, to head of Whipsaw 
creek just east of the Cascade Mountains divide at 5,600 feet elevation. 
Probably ranges south into northern Okanagan county, Washington, 
along heads of Similkameen and Ashnola rivers. 
Diagnostic Characters. A small subspecies, paler and duller in colour 
and smaller than any other known form of the subgenus Mictomys. Skull 
smaller and shorter, with rostrum short. 
Colour. Upper parts uniformly dull brownish grey from nose to 
tail, in some specimens slightly more brownish in mid-dorsal region; 
sides very slightly lighter coloured than back; under parts uniform silvery 
grey, with hairs silvery tipped and deep plumbeous at base. Tail bicolour, 
dark fulvous above, paler below. Feet fulvous. 
External Measurements. Type : total length, 119 (mm.) ; tail vertebrae, 
22; hind foot, 18. Average of six males (four topotypes): total length, 
117-4 (120-115); tail vertebrae, 22 (23-21); hind foot, 18-4 (18-5-18). 
Allotype (female): total length, 115; tail vertebrae, 22; hind foot, 18. 
Average of three females: total length, 116 (120-113); tail vertebrae, 
22 (23-21); hind foot, 17-3 (18-17). (See also table.) 
Skull. Similar in shape in both sexes and noticeably uniform in the 
series at hand; females averaging slightly smaller. Anterior convexity 
of upper incisors projecting 1 or 2 millimetres beyond the tip of nasals, 
making the greatest length of skull slightly more than the occipito-nasal 
length; the greatest length of skull being somewhat less than in S. b. 
chapmani Allen, and considerably less than in S. b. wrangeli Merriam. 
Rostrum comparatively shorter and cranium slightly flatter. 
Skull Measurements. Type (male) : occipito-nasal length, 24; condylo- 
basilar length, 21-5; palatal length, 13; rostral length, 6; rostral breadth, 
3; interorbital breadth, 2*5; zygomatic breadth, 14-2; lambdoidal breadth, 
11*5; mastoidal breadth, 11; incisive foramina, 4; maxillary molar row, 
6-5; mandibular molar row, 7-5; length of nasals, 7-0; height of skull, 
9-5. Allotype (female): occipito-nasal length, 23-2; condylo-basilar 
length, 21; palatal length, 12-5; rostral length, 5-5; rostral breadth, 3-5; 
interorbital breadth, 3; zygomatic breadth, 14; lambdoidal breadth, 11*5; 
mastoidal breadth, 11*5; incisive foramina, 4; maxillary molar row, 6-5; 
mandibular molar row, 7*5; length of nasals, 6-5; height of skull, 9-0 
(See table of comparative measurements). 
Comparisons. The closest relationship of S. b. artemisiae appears to 
be S. b. chapmani , its neighbour on the east, but colour of artemisiae is 
more greyish, paler, and duller, and both external and skull measurements 
are smaller. An adult male specimen taken by the writer on July 18, 
1929, near summit of Green mountain, near Rossland, B.C., in Columbia 
River valley, southwest of the hitherto mapped range of chapmani , is 
