_Comparisons._--From _Dipodomys ordii columbianus_, _D. o. inaquosus_ differs as follows: Size larger; color lighter; skull larger; nasals longer; rostrum longer and wider; interorbital region narrower; braincase more vaulted; interparietal larger; auditory bullae more inflated ventrally; pterygoid fossae subcircular as opposed to nearly circular; zygomatic arches more robust. From _Dipodomys ordii monoensis_, _D. o. inaquosus_ differs in: Size larger; color lighter; skull larger; nasals longer; rostrum wider; interorbital width greater; braincase more vaulted; auditory bullae more inflated laterally, ventrally and posteriorly; interparietal region narrower; pterygoid fossae subcircular as opposed to circular; lacrimal processes larger; foramen magnum ovoid as opposed to circular. _Remarks._--In pallor _D. o. inaquosus_ closely approaches _Dipodomys ordii celeripes_ from eastern Nevada and western Utah. The two populations are separated, however, by a large area inhabited by the darker _Dipodomys ordii columbianus_. Specimens from 18 mi. NE Iron Point, Nevada, which Hall (1946:413) refers to _D. o. columbianus_, are intergrades in color, size and cranial characters and here are referred to _D. o. inaquosus_ instead of to _D. o. columbianus_. Animals from Toulon are intergrades between _D. o. inaquosus_ and _Dipodomys ordii monoensis_ but are referable to the latter. _Specimens examined._--Total, 47, all from Nevada, distributed as follows: _Humboldt County_: 18 mi. NE Iron Point, 4600 ft., 1 (MVZ); 7 mi. N Winnemucca, 4400 ft., 4 (MVZ); 1 mi. N Winnemucca, 4600 ft., 8 (MVZ); 5 mi. NE Golconda, 7 (MVZ); 3 mi. SW Winnemucca, 4500 ft., 1 (MVZ); 4 mi. SW Winnemucca, 4500 ft., 1 (MVZ); 5 mi. SW Winnemucca, 4600 ft., 2 (MVZ); 8 mi. E and 1 mi. N Jungo, 4200 ft., 6 (MVZ); 11 mi. E and 1 mi. N Jungo, 4200 ft., 7 (MVZ); 10 mi. SW Winnemucca, 4500 ft., 1 (MVZ); 23 mi. NW Battle Mountain, 4 (MVZ). _Pershing County_: 15 mi. SW Winnemucca, 1 (MVZ). _Lander County_: Izenhood, 2 (MVZ); 3 mi. S Izenhood, 2 (MVZ). =Dipodomys ordii attenuatus= Bryant _Dipodomys ordii attenuatus_ Bryant, Occas. Papers, Museum of Zool., Louisiana State Univ., no. 5:65, November 10, 1939. _Type._--Male, no. 80429, Museum of Vertebrate Zoology, University of California; Mouth of Santa Helena Canyon, 2146 ft., Big Bend of the Rio Grande, Brewster County, Texas; obtained on November 19, 1938, by Adrey E. Borell, original no. 5581. _Range._--Big Bend region of Brewster County, Texas.