A New Subspecies of Porcupine 7 
in E. dorsatum). The Nebraska animal is larger than this Wis- 
consin specimen (which is 790 mm. long; tail 190; hind foot 93) 
but does not reach the maximum measurements given for E. 
dorsatum by Allen (875—1,000 mm.) and Elliott (goo-1,200 mm. ). 
E. dorsatum picmus Bangs,® from Labrador, with a shorter tail 
(166 mm.) and longer hind foot (124 mm.) than typical E. 
dorsatum, probably differs in much the same color characters. 
Skull—Measurements of the type in millimeters: Total length, 
115.5; basal length, 99; basilar length of Hensel, 95 ; occipito-nasal 
length, 111; zygomatic width, 73; interorbital width, 30; length 
of nasals, 40; width of nasals in front, 21 ; width of nasals behind, 
15.5; length of upper molariform teeth, 27.5; audital bullae, 
21 X 16.5; length of mandible, 83; height of mandible, 36.5. 
Inasmuch as the skulls of Erethizon exhibit considerable sexual 
variation, for a proper analysis of the characters the skulls of the 
sexes are better compared separately. The adult ¢ type skull of 
E. e. brunert compared with the skull of an adult ¢ specimen of 
E. e. epixanthum from California (Whitney Creek, Sierra Nevada 
mountains, August 26, 1911, Storer and Taylor; Coll. Mus. Vert. 
Zool., 16216) differs distinctly in its greater length, comparatively 
shorter and broader rostrum, the much more posteriorly narrowed 
nasals which are more convex when viewed in profile, larger 
audital bullae, less developed depression on the top of the skull 
in the fronto-parietal region, lower lateral borders of interorbital 
region without any knob-like processes posteriorly, and much less 
developed sagittal and occipital crests. The 9 skull exhibits much 
the same differences, only they are less pronounced. The @ para- 
type skull of E. e. brunert compared with the skull of a 9 speci- 
men of E£. e. epixanthum from California (Coll. Mus. Vert. Zool., 
12642) though of the same length is’ distinctly more slender, the 
-nasals are broader and narrow distinctly between the anterior and 
posterior margins (E. e. epixanthum 9 has the nasals narrower 
in front than behind and their sides subparallel), and the audital 
bullae are distinctly larger. The differences in the development 
of the borders of the interorbital region and the sagittal and 
8 Proc. New England Zool. Club, Il, p. 37 (1900). 
I21 
