100 
of Natural Sciences, the American Museum of Natural History in New 
York, and the Field Museum of Natural History in Chicago, and thanks 
are due to the officers of these institutions for permission to study the 
collections, and to the United States Biological Survey for the loan of 
specimens for stud}^. Thanks are also due to Mr. Kenneth Racey, of 
Vancouver, for frequent loans and gifts of specimens and for many interest- 
ing notes on the ecology of the species; also to Mr. H. M. Laing, of Comox, 
for numerous manuscript supplements to his valuable field reports while 
working for the National Museum. 
DESCRIPTIONS OF NEW SPECIES AND SUBSPECIES 
Perognathus laingi new species 
Anarchist Mountain Pocket Mouse 
Type. Male adult, skin and skull, No. 9200, National Museum of 
Canada; Anarchist mountain, near Osoyoos-Bridesville summit, about 
8 miles east of Osoyoos lake, at about 3,500 feet altitude, latitude 49° 08' 
north, longitude 119° 32' west; August 29, 1928; collected by Hamilton 
M. Laing; original No. 956. Allotype: female adult, skin and skull, 
No. 9201, taken at same place and date; original No. 957. 
Geographic Distribution. Known only from type locality; living in dry 
Transition zone habitat at higher elevation than Perognathus lordi , which 
inhabits dry Upper Sonoran zone lowlands of same district. 
Diagnostic Characters. A medium-sized pocket mouse, with compara- 
tively dark, ashy coloration, the blackish tips of dorsal guard hairs 
giving a prevailing dark ashy tone to the coat, instead of the paler and 
more clayey colour of P. lordi and the still more ochraceous wash of P. 
parvus. External measurements and cranial measurements average smaller 
than lordi and larger than parvus ; ratio of interparietal width to condylo- 
basal length averaging 26-4 mm. in males and 26-3 in females. 
Colour. Upper parts glossy, uniformly mixed dusky greyish from 
face to base of tail, hairs plumbeous at base, slaty buff in middle section, 
and generally tipped with black; top of crown and mid-dorsal region 
slightly darker than sides, but with no well-defined median line; nose 
buffy grey, bordered posteriorly by an obscure blackish V with apex 
above tip of nose and arms extending laterally along cheeks and merging 
with the ashy of shoulders; ears small, dull grey, with obscure whitish 
edgings; area around eye pale greyish; sides lighter coloured than back, 
with a very faint buffy line where the flanks merge with the pure white 
of under parts; tail bicolour, pale greyish above, white below; under parts 
entirely white; fore feet and hind feet white. 
External Measurements. Type: total length, 191 (mm.); tail verte- 
brae, 102; hind foot, 25. Average of four adult males (topotypes): total 
length, 175-5 (191-0-158-0); tail vertebrae, 90-3 (102*0-69-0); hind foot, 
23-8 (25-0-22-5). Allotype (female): total length, 165; tail vertebrae, 88; 
hind foot, 22. 
