_Diagnosis._--Size small (see measurements). Color light, entire dorsal surface between Pinkish Buff and Pinkish Cinnamon, purest on sides and flanks, upper parts but lightly mixed with black; cheeks and narrow outer margin of ear, pure white; arietiform markings absent; pinnae of ears, dorsal and ventral stripes of tail, brownish; plantar surfaces of hind feet, blackish. Skull small; rostrum long and narrow; nasals short; interparietal longer than wide; auditory bullae longer than deep. _Comparisons._--Compared with _Dipodomys ordii ordii_, _D. o. attenuatus_ differs in: Size smaller; color lighter; skull smaller; nasals thinner; rostrum narrower; auditory bullae less inflated. From _Dipodomys ordii richardsoni_, _D. o. attenuatus_ differs in smaller size and lighter color. Skull smaller in all respects. For comparison with _Dipodomys ordii sennetti_ see account of that subspecies. [Illustration: FIG. 27. Known occurrences and probable geographic range of the subspecies of _Dipodomys ordii_ in the northwestern fourth of the range of the species. 9. _D. o. panguitchensis_ 20. _D. o. fetosus_ 28. _D. o. inaquosus_ 10. _D. o. uintensis_ 21. _D. o. utahensis_ 31. _D. o. longipes_ 11. _D. o. sanrafaeli_ 22. _D. o. columbianus_ 32. _D. o. pallidus_ 12. _D. o. fremonti_ 24. _D. o. priscus_ 33. _D. o. nexilis_ 13. _D. o. monoensis_ 25. _D. o. celeripes_ 34. _D. o. cupidineus_ 17. _D. o. chapmani_ 26. _D. o. cineraceus_ 19. _D. o. cinderensis_ 27. _D. o. marshalli_ ] _Remarks._--This small race of _Dipodomys ordii_ was known formerly only from the type locality. This study has shown it to range northward and slightly westward. At four places, 6, 20, and 47 miles south of Marathon and 10 miles west of San Vicente, Texas, this race can be said to be typical, in that specimens from these places agree with those from the type locality. At two other localities, 5 miles east of Toyahvale and Kent, Texas, animals show an intergrading tendency toward _Dipodomys ordii ordii_. The animals from these latter places are darker colored and are intermediate in size and cranial characters. Since these animals show more resemblance to _D. o. ordii_ in the majority of characters they are referred to that race, rather than to _D. o. attenuatus_. _Specimens examined._--Total, 14, all from Texas, distributed as follows: _Brewster County_: 6 mi. S Marathon, 1 (USBS); 20 mi. S Marathon, 1 (USBS); Cooper's Well, 47 mi. S Marathon, 4 (MVZ); 10 mi. W San Vicente, 1 (UM); Johnson's Ranch, Big Bend Rio Grande, 4 (2 TCWC; 2 UM); mouth Santa Helena Canyon, 3 (1 TCWC; 2 MVZ). =Dipodomys ordii fuscus= new subspecies _Type._--Male, adult, no. 93886, U. S. Nat. Mus., Biol. Surv. Coll.; Juamave, Tamaulipas, Mexico; obtained on June 3, 1898, by E. W. Nelson and E. A. Goldman, original no. 12437.