Great Salt Lake has not been so effective in isolating the animals living on the islands as heretofore has been thought. After these supposedly isolated kinds of animals from Great Salt Lake were named, some other workers have shown several of the kinds to have extensive ranges on the mainland. Some of the kinds ranging also on the mainland are: _Dipodomys ordii marshalli_, _Dipodomys microps subtenuis_ and _Peromyscus crinitus pergracilis_. Of the animals named from the islands, I suppose that those which require the semiarid habitat found in this area will all be found to have large ranges on the adjacent mainland and that each of the kinds of animals which do not require the above habitat, and which lived in this region during the Pleistocene, will be found to be restricted to the island from which it was named. _Specimens examined._--Total, 47, all from Utah, distributed as follows: _Box Elder County_: Kelton, 4300 ft., 7 (5 MVZ; 2 UU). _Tooele County_: 2 mi. W Grantsville, 1 (CAS); Bird Island, Great Salt Lake, 4300 ft., 1 (USNM); Carrington Island, Great Salt Lake, 4300 ft., 1 (USNM); Stansbury Island, Great Salt Lake, 4300 ft., 10 (6 UU; 4 USNM). _Salt Lake County_: 18 mi. W Salt Lake City, 4260 ft., 16 (UU); 17 mi. W Salt Lake City, 4320 ft., 7 (UU); 16 mi. W Salt Lake City, 4300 ft., 3 (UU); 14 mi. W Salt Lake City, 4300 ft., 1 (UU). =Dipodomys ordii inaquosus= Hall _Dipodomys ordii inaquosus_ Hall, Proc. Biol. Soc. Washington, 54:58, May 20, 1941. _Type._--Male, adult, no. 73580, Museum of Vertebrate Zoology, University of California; 11 mi. E and 1 mi. N Jungo, 4,200 ft., Humboldt County, Nevada; obtained on July 26, 1936, by Ward C. Russell, original no. 5026. _Range._--Southeastern Humboldt and northern Lander counties, Nevada; marginal occurrences, all in Nevada, are: 7 mi. N Winnemucca, 8 mi. E and 1 mi. N Jungo, 15 mi. SW Winnemucca, 23 mi. NW Battle Mountain, Izenhood, and 18 mi. NE Iron Point. _Diagnosis._--Size medium (see measurements). Color pale, entire dorsal surface Pinkish Buff, purest on sides and flanks with but slight suffusion of black on the upper parts; cheeks white; arietiform marks indistinct, pinnae of ears, plantar surfaces of hind feet, dorsal and ventral stripes of tail, brownish. Skull medium in size; rostrum short and wide; nasals relatively long and expanded distally; braincase but slightly vaulted; interorbital width narrow; extension of premaxillae posterior to nasals relatively great; interparietal relatively large; pterygoid fossae subcircular; foramen magnum ovoid; auditory bullae relatively greatly expanded ventrally.