228 NORTH AMERICAN FAUNA [No. 55 



APLODONTIA RUFA PACIFICA MEBRIAM 

 PACIFIC MOUNTAIN BEAVEB 



Aplodontia paciftca Merriam, Biol. Soc. Wash. Proc. 13: 19, January 31, 1899. 



Type. Collected at Newport, on Yaquina Bay, Oreg., by B. J. Bretherton 

 in 1896. 



General cliaracters. Noticeably smaller than rufa with conspicuously nar- 

 rower, slenderer skull, and slightly darker colors; generally more dusky on 

 head and back and the basal ear spots mainly or wholly dusky instead of 

 white. 



Measurements. Adult male at Astoria : Total length, 303 mm ; tail, 20 ; foot, 

 53; ear in dry specimens, 16 to 20. 



Distribution and habitat. This is a coast form, extending prac- 

 tically the whole length of the Oregon coast and inland to the open 

 valley country (fig. 51). Specimens from Eugene show characters 

 intermediate between rufa and paeifica, but seem to be nearer to 

 pacifica. Over the heavily timbered and densely brush-covered 

 slopes of this humid area they are more generally distributed than 

 are those of the mountain form of the drier interior range, but even 

 here they are more or less colonial or localized in the areas occupied, 

 and often absent for wide intervals. 



General habits. Only as modified by the type of country are their 

 habits different from those of the larger rufa. More often they are 

 located on the broad slopes of the mountains and hillsides, where in 

 the long rainy season there is abundance of water to trickle through 

 their burrows. In places the slopes are fairly honeycombed by the 

 burrows. A group of burrows may have 20 openings scattered over 

 a few square rods of ground, some with considerable mounds of earth 

 thrown out and others without a trace of earth around the mouth. 

 Surface trails often lead from one burrow to another or out into brush 

 or fern patches nearby. Many of the shallow tunnels have been 

 broken into from above and often the line of a burrow may be 

 traced for considerable distance. 



Food habits. In the coastal region their favorite or most generally 

 available food plants seem to be salmonberry, thimbleberry, huckle- 

 berry bushes, and the abundant ferns about their burrows. They 

 also cut the branches from alders, vine maples, hemlocks, and cedars, 

 and carry them to their burrows, supposedly for food. Many other 

 plants are eaten and sometimes all of the bushes around their colonies 

 are cut down until only stumps remain, but as these are mainly unim- 

 portant growth and spring up again with the next growing season, 

 the food supply is perennial and abundant. In examining large 

 numbers of colonies the writer has not found where any number of 

 young or larger trees had been injured by them. 



Family ERETHIZONTIDAE: American Porcupines 



ERETHIZON EPIXANTHUM EPIXANTHUM BRANDT 



YELLOW-HAIRED POBCTJPINE 



Erethizon epixanthus Brandt, Mem. Acad. Imp. Sci., St. Petersbourg (6) 

 3:390, 1835. 



Type locality. California. 



General characters. Next to the beaver our largest rodent; form short and 

 broad, with short legs and short muscular tail; feet fully plantigrade, with 



