478 University of California Publications in Zoology — [Vou. 17 
maxillaries (often posterior of this point in rufa); shallow embay- 
ment in lateral outline of nasals posteriorly (variable in rufa) ; ros- 
trum and nasais longer in californica, zygomatic arches squarer ante- 
riorly, caliber of audital tubes averaging greater (about equal to eali- 
ber in typical rufa). From A. r. rainieri, californica differs in the 
following skull characters: nasals tending to be broadest at a more 
anterior point; a more pronounced tendency observable toward ap- 
proximation of temporal ridges; heavier zygomatic arches, squarer 
anteriorly ; and great caliber of audital tubes. 
CRANIAL MEASUREMENTS OF Aplodontia rufa californica (14 SKULLS) 
Average Mean Maximum Minimum 
Bastar Wen gts cccyesc ese sseece Necro eee 61.1 62.4 65.1 59.6 
Length of nasals (8 skulls) 26.8 26.9 28.4 25.4 
Widthvot masals, -- see iei 12.0 12.8 11.2 
Length of audital tube (12 skulls) -.. 19.1 18.9 20.5 WEP) 
Length of incisive foramen ... 7.6 7.6 8.2 7.1 
Zygomatic width .......2...-...-... 57.6 57.0 60.9 53.1 
Greatest width of interpterygoid fossa 5.2 5.2 5.8 Awl 
Mastoid width of cranium .............. 54.2 53.9 57.0 50.7 
Alveolar length of superior cheek teeth 19.6 19.6 20.7 17.5 
Distance between infraorbital foramina .-.... = 16 17.4 18.4 16.4 
Mandible, transversely across angular process ... 24.5 24.4 26.6 22.1 
Mandible} greatest length) [= ee 50.5 49.9 53.2 46.7 
EXTERNAL MEASUREMENTS OF Aplodontia rufa californica (17 SKINS) 
Average Mean Maximum Minimum 
Total length 352 352 380 325 
JERUOCL BHO OLE se coreerpeceteeecceuetore ce 60 59 64 Bis) 
Cranial measurements of three males from Blue Cafion, California: basilar 
length, 64.3, 63.1, 62.8; length of nasals, 29.1, 27.0, 27.0; width of nasals, 12.6, 
13.0, 12.8; zygomatic width, 61.9, 61.4, 61.2; mastoid width, 59.4, 59.9, 57.9. 
Cranial measurements of three females from the same locality: basilar length, 
60.7, 61.9, 60.5; length of nasals, 27.6, 27.2, 27.0; width of nasals, 12.0, 11.9, 12.2; 
zygomatie width, 55.5, 60.9, 57.8; mastoid width, 53.4, 57.9, 54.8. 
Californica is one of the more consistent subspecies of Aplodontia 
rufa, maintaining its characters with considerable uniformity through- 
out its range. Still, a series of specimens from Mount Shasta, Cali- 
fornia, while indistinguishable cranially from typical californica, is 
characterized by slightly darker coloration dorsally. 
Squareness anteriorly of the zygomatic arches and outline of the 
nasals in specimens of rufa from Mount Mazama in southern Oregon 
suggest intergradation with californica, as do also certain cranial 
characteristics of examples from Canon Creek, California. The latter 
exemplify a tendency to combine the square zygomatic arches and the 
distinctive nasal outline of californica with the short rostrum and 
browner coloration of rufa. 
