28 TVr TT.F. TTV 1091, U. 8. DEPARTMENT OE AGEICEXTTTRE. {bK^ 
The following plants not represented in the list stored by the 
kangaroo rat on the Kange Reserve have been found in the cheek 
pouches or mounds of spectabUis in other localities : 
Amaranth us palmeri, Sesuvium port ula cast rum, and Atriplejt icrightii (allu- 
vial soil of Santa Crnz Valley. Continental, Ariz.. Bailey). 
Cut leaves and stems of a small sagebrush i Franklin Mountains, Tex. r Gaut). 
Gutierrezia heads (San Juan Valley, X. Mex.. Birdseye). 
Verbesma enceliodes, Portulaca oleracea, Bouteloua gracilis, and Munron 
■squarrosa (Rio Alamosa, N: Mex.. Goldman). 
Tops of buds of Artemisia fi.lifolia (Mesa Jumanes. X. Mex.. Gaut). 
Tunibleweed (Amaranth us graecizans), Russian thistle i Sal-sola pestifer). 
Mumroa squarrosa, and Sporooolus cruptandrus strictus (Sandia Mountains. Al- 
buquerque. X. Mex.. Vorhies'. 
BURROW SYSTEMS. OR DENS. 
The burrow system, or den. in which spectabUis stores its caches of 
food materials, has its nest, and remains throughout the hours of day- 
light is a complicated labyrinth of tunnels. Ejection of refuse and 
soil from this retreat builds up the mound frequently referred to. 
These mounds are. as Bailey says, characteristic of the species, and 
are as unmistakable as muskrat houses or beaver dams, and as care- 
fully planned and built for as definite a purpose — home and shelter. 
They are. furthermore, the most notable of all kangaroo rat dwelling 
places (Xelson. 1918. 100) . They range in height from 6 inches to 
approximately 1 feet and from 5 to 15 feet in diameter. 
The mound is built up not only through the cleaning out of chaff' 
and other food refuse, but through extension and modification of 
the tunnels : old tunnels, entrances, and caches of musty food material 
are from time to time closed up and others excavated, repair and re- 
building being especially necessary after the collapse of portions 
of the den as a result of heavy rains or trampling by cattle. Ejected 
material is most commonly simply thrown out fan-wise from the 
openings, without much apparent effort to add to the height of the 
mound. 
There are usually from 6 to 12 entrance holes in each mound 
opening into the subterranean burrow system, each hole from 1 to 
5§ inches in diameter. These holes are nearly all situated a little 
above the surface of the surrounding soil, and as Price has suggested 
(in Allen. 1S95. 213). this is doubtless a wise provision against flood- 
ing, as torrential rains sometimes occur in the kangaroo rat country. 
Both Bailey and Xelson state that as a rule several of the holes 
are closed with sand or miscellaneous earth and old storage material 
during the daytime, but our observations on the Range Reserve are 
that such closing is only occasional. Many occupied dens have not 
