1918] Taylor: Revision of the Rodent Genus Aplodontia 479 
Aplodontia rufa nigra Taylor 
Point Arena Aplodontia 
Aplodontia nigra Taylor (1914), pp. 297-300. 
Type—Male adult; no. 20320, Mus. Vert. Zool.; Point Arena, 
Mendocino County, California; July 10, 1913; collected by ©. L. 
Camp; orig. no. 1003. 
Specimens Examined.—Total number 4, all from California: Men- 
docino County—Point Arena. 
Geographic Range-—Known only from the type locality, where it 
is found within an area of approximately twenty-four square miles. 
Cramal Characters—Skull moderate in size (see measurements 
below) ; nasals dilated anteriorly, comparatively contracted poste- 
riorly ; zygomatic arch medium in weight, squarish anteriorly ; position 
of postorbital process faintly indicated ; temporal lines or ridges not 
closely approaching ;. incisive foramina short; noteh dorsally on ex- 
ternal auditory meatus deeper than in Aplodontia rufa humboldtiana, 
more as in A. r. pacifica. 
External Characters—Summer specimens, above shiny black, with 
a sparse insprinkling of pinkish buff hairs and with plumbeous bases 
of the hairs showing through to a certain extent, the whole giving the 
impression of shiny black faintly sprinkled with grayish; sides paler 
than back, prevailingly pinkish buff, with heavy insprinkling of black 
hairs; head tending to be shiny black; face dark quaker drab; under- 
parts cinereous to plumbeous, lightly washed with pinkish buff. 
Age Variation—This subspecies exhibits a remarkable similarity 
in the characters of adult and young. The coal black dorsal color- 
ation, as well as the anterior dilation of the nasal outline, are conspic- 
uous in both. In one young example (no. 20321, Mus. Vert. Zool.) 
a single small bony element is marked off by sutures in the inter- 
parietal region. The zygomata are decidedly heavier in the adult than 
in the young, as well as somewhat more expanded anteriorly. 
Molt—Three young at hand (nos. 20318, 20319, and 20321, Mus. 
Vert. Zool., taken July 9 to 11) are molting from the juvenal pelage 
into that of the adult. The new pelage is more intensely brown and 
black than the gray-black pelage of the juvenal, the brown being more 
emphasized laterally, the black dorsally. 
Remarks —Aplodontia rufa nigra is the most strikingly marked 
subspecies of mountain beaver known, its dorsal coloration rendering 
