Ill 
Diagnostic Characters. Resembles P. m. oreas Bangs more closely 
than any other form, but considerably larger and slightly darker than 
oreas on back and with richer shade of rusty or cinnamon on sides; much 
larger and not as dark in colour as P. m. austerus (Baird). 
Colour. Upper parts greyish brown, darker along median line; face 
greyish, slightly washed with reddish; a blackish spot at base of whis- 
kers, and a sooty ring around eye; feet white; forearms dusky; ankles 
brownish; tail dark brown above, whitish below; under parts white. 
External Measurements. Type: total length, 215; tail vertebrse, 115; 
hind foot, 22-5; ear (from dried skin), height 20, greatest width 12. Breed- 
ing specimen, with testes 10 by 7 mm. Average of two male topotypes: 
total length, 209*5 (215*0-204*0); tail vertebrae, 111*5 (115*0-108*0); 
hind foot, 22*5. Allotype (female): total length, 218; tail vertebrae, 115; 
hind foot, 22. 
Skull. Proportions similar to those of P. m. oreas of similar age, 
but somewhat larger. 
Skull Measurements. Type (male): occipito-nasal length, 28 (mm.); 
condylo-basal length of Hensel, 21; zygomatic breadth, 13*2; interorbital 
breadth, 4*2; interparietal length, 3*5; interparietal breadth, 9*5; length 
of nasals, 12; shelf of bony palate (from posterior end of anterior palatine 
foramina to anterior border of interpterygoid fossa), 5; palatine slits, 5; 
diastema (from anterior border of upper molars to posterior base of in- 
cisors), 7*2; postpalatal length, 9*5; maxillary tooth row, 4; mandibular 
tooth row, 4; height of skull, 9*5. Allotype (female) : occipito-nasal length, 
26*5; condylo-basal length, 20*5; zygomatic breadth, 13; interorbital 
breadth, 4; interparietal length, 3; length of nasals, 11; shelf of bony 
palate, 4; palatine slits, 5*5; diastema, 7; postpalatal length, 9*5; maxil- 
lary tooth row, 4; mandibular tooth row, 4*2; height of skull, 10. 
Comparisons. The only white-footed mouse hitherto reported from 
the mainland of Vancouver island is P. m. austerus (Baird), and austerus 
is easily differentiated from interdictus by its much smaller size and 
shorter tail (length usually not over 190 and tail not over 95, usually much 
less), and by the sooty mid-dorsal region of austerus. P. m. interdictus 
is also much larger than P. m. saturatus Bangs, known only from 
Saturna island in the strait of Georgia, and P. m. hollisteri Osgood, known 
only from San Juan island, San Juan county, Washington. P, m. 
interdictus bears the closest resemblance to P. m. oreas Bangs, but the 
latter is not known to occur off the mainland of British Columbia and the 
State of Washington, and interdictus is larger and darker in colour than 
oreas. 
Remarks. The National Museum of Canada has two specimens taken 
by William Spreadborough at Nootka, on west coast of Vancouver island 
(No. 1304 $, May 30, 1907, and No. 1306 d% June 3, 1907), without 
skulls or measurements, but which the writer for some time had placed 
with P. m. oreas from evident large size, length of tail, and approximately 
similar colour. Mr. H. S. Swarth 1 records 203 specimens of P. m. austerus 
‘Report on a Collection of Birds and Mammals from Vancouver island; Univ. of California Pub. in Zoology, 
vol. 10, No. 1, p. 95 (February 13, 1912). 
