1918 ] Camp: Burrows of the Rodent Aplodontia 521 
entrances on the hillside were connected with one another by passages 
six to eighteen inches beneath the surface. At one point a nest was 
discovered half fillmg a globular chamber about a foot in diameter 
(see fig. 2). The nest was constructed for the most part of dry 
sword fern ‘‘leaves’’ stripped from the frond stem. It also contained 
a few large dry leaves of the cow parsnip, a plant nearly everywhere 
found in the vicinity of the burrows. Some dirt was mixed with the nest 
and the whole had been trampled down into a firm mass, flat on top. 
EARTHEN PELLETS £ 
STORED Foo0 6 
450-0 
re 
ONE METER 
TAREC Feet 
Fig. 2. Plan and partial elevation of nest-galleries of Aplodontia rufa phaea 
excavated near Point Reyes, Marin County, California. Numbers on plan 
indicate depth in millimeters beneath surface of ground. 
Adjoining the nest chamber in the excavation mentioned, and opening 
into it, was a low square ‘‘room’’ twenty inches in diameter, the floor 
and sides of which showed signs of continued use by the inhabitants. 
Pockets near by contained stored roots, stems and leaves carefully 
blocked in by artificial earth pellets (see fig. 2). 
Aplodontia rufa nigra, at Point Arena, Mendocino County, Cali- 
fornia, the closest relative of A. r. phaea, and A. r. hwmboldtiana, of 
the Humboldt Bay region and farther north, both apparently have 
burrow systems similar to that of phaea described above. Like phaea, 
mgra inhabits thimbleberry thickets. It lives on north-facing guleh 
sides in a small area (about twenty-four square miles) along the cen- 
