468 University of Califorma Publications in Zoology | Vou. 17 
Cranial Characters ——Skull comparatively small (sée measurements 
beyond) ; nasals broad anteriorly, becoming only a little narrower 
posteriorly, fairly uniform in outline through the series, comparatively 
straight laterally, with little or no anterior dilation; temporal lines 
or ridges not strongly marked, never approximated, though sometimes 
approaching to within a few millimeters of one another anteriorly ; 
zygomatic arches comparatively light in weight, with weakly devel- 
oped postorbital processes in certain specimens; fossae in front of 
lambdoidal ridge shallow; audital tubes of small caliber, notch dor- 
sally in tubes short and broad; averaging smaller, on the basis of 
specimens measured, than Aplodontia rufa rufa, A. r. olympica, or 
A. r. humboldtiana in basilar length, width of nasals, length of audital 
tube, zygomatic width, mastoid width, alveolar length superior cheek 
teeth, distance between infraorbital foramina, and greatest length of 
mandible. 
External Characters——Aboye, in winter specimens, sayal brown 
or cinnamon to pinkish cinnamon, in one specimen (no. 9077, Field 
Mus. Nat. Hist.) approximating pinkish buff; many glossy black hairs 
interspersed, especially on back; top of head usually conspicuously 
black ; in most specimens a black area or ill-defined broad band starting 
at nose and continuing back over head and posteriorly along middle 
of back to posterior end of body, this indefinite band grading into the 
browner coloration of the sides; face grayish in most examples ; under- 
parts grayish, with a more or less distinct brown wash varying from 
cinnamon or pinkish cinnamon to warm buff or pinkish buff. 
CRANIAL MEASUREMENTS OF Aplodontia rufa pacifica (23 SKULLS) 
Average Mean Maximum Minimum 
Basilarslentott hye eee Be ice eee 57.0 57.5 62.1 52.9 
Length of nasals (19 skulls) a BASES 23.9 26.5 21.4 
Wal Gh fea. caill eee ene eee eee -- 10.4 10.5 11.4 9.6 
Length of audital tube (15 skulls) 16.8 16.8 17.9 15.7 
Length of incisive foramen ........... cao, MTHS) 6.6 7.7 5.5 
Ley feqOssTEH AKG NKR See en =) 015 51.6 56.1 47.1 
Greatest width of interpterygoid fossa ............. 4.6 4.4 5.3 3.5 
Mastoid width of cranium (22 skulls) —....-.... 49.1 — 50.0 52.9 47.2 
Alveolar length superior cheek teeth ....... =e SiG 18.6 20.3 16.9 
Distance between infraorbital foramina = 6:0 15.8 17.5 14.1 
Mandible, transversely across angular process ... 22.5 23.1 25.3 20.9 
Greatest length of mandible (22 skulls) ......... 45.7 45.6 49.4 41.9 
EXTERNAL MEASUREMENTS OF Aplodontia rufa pacifica (23 SKINS) 
Average Mean Maximum Minimum 
Motall len gihye eases 316 324 356 293 
Hing) footw ee 51 52 57 48 
