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
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
| 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.
Range.—Nuevo León, extreme northern Zacatecas, Tamaulipas and northern San Luis Potosí, Mexico; marginal occurrences are: Coahuila, La Ventura; Tamaulipas, Tula, Juamave and Nuevo Laredo.
Diagnosis.—Size medium (see measurements). Color dark, entire dorsal surface (a) between Cinnamon-Buff and Clay Color, purest on sides, flanks and cheeks, upper parts strongly suffused with black; posterior surfaces and fold of pinnae of ears, white; arietiform markings, plantar surfaces of hind feet, inside of pinnae of ears, dorsal and ventral stripes of tail, blackish. Skull of medium size; nasals relatively short; interorbital width narrow; auditory bullae relatively as well as actually greatly inflated posteriorly, laterally and ventrally; braincase vaulted; zygomatic arches light and straight; pterygoid fossae ovoid; rostrum short and wide.