B44 University of California Publications in Zoology. \Veou.5 
Erethizon epixanthum myops Merriam. Alaska Porcupine. 
Six specimens, three from Port Nell Juan and three from 
Cordova Bay. Four of these are fully adult and in coloration 
are quite yellowish, the dark hairs having little effect on the 
general coloration. 
None of the skulls in this series is large in comparison with 
the largest in the series of fifty from the Kenai Peninsula. The 
skull of a female from Port Nell Juan, however, is much older 
than any other examined, but it is rather undersized. This 
skull (no. 988) has lost all traces of sutures except the nasals, 
and has the crowns of the molars worn down until the enamel 
indentations have disappeared. It measures: Hensel 86 mm.; 
zygomatie width 70. The individual variation in size, inde- 
pendent of age or sex, shown by this large series of fifty skulls 
is immense. The variation in the relative size of the audital 
bulla is especially great. 
The trees most used for food were the Sitka spruce and the 
mountain hemlock. At Cordova Bay and at Port Nell Juan 
large patches of the bark near the base of these conifers had 
been removed by these rodents. Most of the work was done at 
the base and on one side only, a tree very seldom being found 
eirdled. Oceasional patches of gnawing at the base of large 
limbs where the animal could obtain convenient support while 
working were observed at considerable distances above the foot 
¢ 
of the tree. This sort of porcupine ‘‘sign’’ was especially notice- 
able at the shore line and often on the horizontal limbs of trees 
projecting over the water. 
One evening a poreupine was found at Cordova Bay feeding 
well out on one of these limbs projecting above the water. The 
linb was chopped off and fell with the porcupine into the salt 
water of the bay. The poreupine on rising to the surface after 
his plunge struck out vigorously for the shore. This means of 
escape was eut off several times by the- vigorous use of an oar, 
and the porcupine eventually was hauled aboard the boat en- 
snared in the coils of the painter. He proved himself to be a 
vigorous swimmer, the great buoyaney of his quills floating him 
well out of the water. 
