1918 | Taylor: Revision of the Rodent Genus Aplodontia 457 
ber 29 and October 9, respectively, show the last stages of the process; 
and the molt is entirely completed in a specimen taken November 21. 
Evidently August, September and October are the principal months 
of molt. 
Seasonal changes are trifling. The fresh pelage is longer and 
tends to be somewhat browner, sometimes blacker, than in its hold- 
over stage in spring and early summer. 
CRANIAL MEASUREMENTS OF Aplodontia rufa rufa (13 SKULLS) From Marnor, 
VIDA AND VICINITY OF MCKENZIE BRIDGE, OREGON 
Average Mean Maximum Minimum 
Basilar length 61.1 57.2 
Length of nasals (10 skulls) —. 27.3 23.0 
Width of nasals 13.3 11.5 
Length of audital tube (10 skulls) . 21.0 16.0 
Length of incisive foramen 8.7 5.7 
Zygomatie width 59.6 49.5 
Mastoid width of cranium ............ 59.0 47.4 
Alveolar length superior cheek teeth 119°9 18.2 
Distance between infraorbital formamina ~.... 16.4 17.8 15.0 
Mandible, transversely across angular process... 23.1 22.4 25.0 ie) 
Mandible, greatest length (12 skulls) .......... 46.2 46.0 48.7 43.5 
EXTERNAL MEASUREMENTS OF Aplodontia rufa rufa, FROM VIDA AND 
I 
VICINITY OF MCKENZIE BRIDGE, OREGON 
Average Mean Maximum Minimum 
Total length (9 skims) ~............ 345 348 387 310 
letihayel SHoyoyr. (C7 fbr sis), eeepc eee eae 56 56 59 54 
CRANIAL MEASUREMENTS OF Aplodontia rufa rufa (12 SKULLS), FROM THE VICINITY 
oF SEATTLE AND Mount BAKER RANGE, WASHINGTON, AND THE 
CHILLIWACK-SuMAS District, BRITISH COLUMBIA 
Average Mean Maximum Minimum 
Basilar length 59.6 59.5 62.1 57.0 
Length of nasals (10 skulls) 25.2 27.2 23.2 
Width of nasals 11.5 12.8 10.2 
Length of incisive foramen ell 8.1 6.2 
Zygomatic width ............ Peeters 55.5 54.1 58.9 49.3 
Greatest width of interpterygoid fossa .......... 5.0 5.0 5.8 4.2 
Mastoid width of cranium ~................... 25222 52.5 55.7 49.4 
Alveolar length of superior cheek teeth geil 20.0 18.3 
Distance between infraorbital foramina 16.4 17.6 15.2 
Mandible, transversely across angular process... 23.0 25.9 20.2 
Mandible, greatest length 47.6 47.3 49.5 45.1 
EXTERNAL MEASUREMENTS OF Aplodontia rufa rufa (9 SKINS), FRoM THE VICINITY 
OF SEATTLE, WASHINGTON, AND CHILLIWACK, BRITISH COLUMBIA 
Average Mean Maximum Minimum 
Total length ... 332 345 318 
Hind foot 56 58 54 
