458 University of California Publications in Zoology (Vou. 17 
CRANIAL MEASUREMENTS OF Aplodontia rufa rufa (7 SKULLS), FRoM TRINITY 
AND SISKIYOU COUNTIES, CALIFORNIA 
Average Mean Maximum Minimum 
Basilar length 59.3 59.8 61.8 57.9 
Length of nasals (6 skulls) .. 24.5 26.2 22.9 
Width of masals) ---------- 11.8 13.0 10.7 
Length of audital tube .... 19.1 19.4 21.1 17.7 
Length of incisive foramen ws Ue 7.2 7.6 6.7 
Zi; FOU ULC avy Cit Np ae sees es neces tae sees teat rece oee stoner 56.1 55.9 60.4 51.4 
Greatest width of interpterygoid fossa —....... 5.1 5.1 5.3 4.8 
Mastoid width of cranium ....................... 3.6 54.3 58.2 50.4 
Alveolar length superior cheek teeth --- 18.8 18.7 19.2 18.2 
Distance between infraorbital foramina ...... 16.5 16.3 18.2 14.4 
Mandible, transversely across angular process... 24.0 23.9 26.0 21.7 
Mandible, greatest length —......-.-.---------------: 48.3 enor 51.3 44.5 
EXTERNAL MEASUREMENTS OF Aplodontia rufa rufa (7 SKULLS), From TRINITY 
AND SISKIyoU COUNTIES, CALIFORNIA 
Average Mean Maximum Minimum 
340 370 310 
59 58 63 53 
Total length 
Elinid! footie. 
Averages of External Measurements: Four specimens from Easton, Wash- 
ington: total length, 354 mm. (345-368); hind foot, 59 (58-63). Eighteen 
specimens from Siskiyou, Oregon: total length, 332 (310-394); hind foot, 58 
(52-63). Ten additional examples from the Siskiyou Mountains, California: 
total length, 349 (320-370); hind foot, 55 (53-58). Two specimens from Ash- 
land Peak, Oregon: total length, 340, 352; hind foot, 60, 63. Two examples from 
Anna Creek, Mount Mazama: total length, 360, 385; hind foot, 58, 61. Three 
specimens from Fort Klamath, Anna Creek Canyon: total length, 333, 338, 370; 
hind foot, 54, 60, 57. Three specimens from Canyon Creek, California: total 
length, 345, 360, 370; hind foot, 60, 60, 60. 
Remarks —Aplodontia rufa rufa is a variable form embracing a 
number of local forms, some of which, if their extremes only were 
considered, would certainly rank as good subspecies. The number 
of these local variants (which have been noted from the Chilliwack- 
Sumas district, British Columbia; vicinity of Seattle, Puget Sound, 
Washington; Ashland Peak, Siskiyou and Fort Klamath, Oregon; the 
Siskiyou Mountains and Canyon Creek, California; and elsewhere), 
coupled with the great range of individual variation observable in 
series from the same general locality, make impracticable the recogni- 
tion of subspecies within the range of A. r. rufa as here outlined. 
Specimens of rufa from the immediate vicinity of Seattle, Wash- 
ington, tend to have narrower nasals and rostra, mastoid width less, 
audital tubes of smaller caliber, and fossae set off anteriorly by lamb- 
doidal ridge shallower than in typical material from Marmot, Oregon. 
