Any of the food materials above listed are likely to be found in the cheek pouches, while in addition such extraneous matter as stones and feces have also been found. All species of plants stored are accessible in the immediate vicinity of the mound, and when any particular plant is found seeding in abundance in the vicinity of the den it is likely to be represented in the storage. Usually the animals can be readily trapped with almost any kind of grain bait, as oats, rolled oats, rolled barley, and wheat; and nut meats also are attractive, though we have no record of the storing of any true nut in the dens, such not being available in the range of the animal on the Range Reserve. The following plants not represented in the list stored by the kangaroo rat on the Range Reserve have been found in the cheek pouches or mounds of _spectabilis_ in other localities: _Amaranthus palmeri_, _Sesuvium portulacastrum_, and _Atriplex wrightii_ (alluvial soil of Santa Cruz Valley, Continental, Ariz., Bailey). Cut leaves and stems of a small sagebrush (Franklin Mountains, Tex., Gaut). _Gutierrezia_ heads (San Juan Valley, N. Mex., Birdseye). _Verbesina enceliodes_, _Portulaca oleracea_, _Bouteloua gracilis_, and _Munroa squarrosa_ (Rio Alamosa, N. Mex., Goldman). Tops of buds of _Artemisia filifolia_ (Mesa Jumanes, N. Mex., Gaut). Tumbleweed (_Amaranthus graecizans_), Russian thistle (_Salsola pestifer_), _Munroa squarrosa_, and _Sporobolus cryptandrus strictus_ (Sandia Mountains, Albuquerque, N. Mex., Vorhies). BURROW SYSTEMS, OR DENS. The burrow system, or den, in which _spectabilis_ stores its caches of food materials, has its nest, and remains throughout the hours of daylight 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 carefully planned and built for as definite a purpose--home and shelter. They are, furthermore, the most notable of all kangaroo rat dwelling places (Nelson, 1918, 400). They range in height from 6 inches to approximately 4 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 rebuilding 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.