_Comparisons._--Compared with topotypes of _Thomomys bottae trumbullensis_, _absonus_ differs in: Size smaller. Color: Markedly lighter throughout. Skull: Smoother, less angular; zygomatic arches weak as opposed to robust; nasals more convex as viewed laterally; extension of premaxillae posterior to nasals less; ascending processes of premaxillae narrower; palate narrower; palatal pits shallower; rostrum narrower; molariform teeth smaller.
For comparisons of _absonus_ with _Thomomys bottae aureus_ see account under that form.
Among named races of _Thomomys bottae_, _absonus_ most closely resembles _planirostris_, but can be distinguished from the topotypes as follows: Size markedly smaller. Color: Lighter, more buffy throughout. Skull: Smaller, less ridged and more nearly flat; nasals convex as opposed to flat; extension of premaxillae posterior to nasals less; width of ascending processes of premaxillae less; zygomatic arches weaker; palate narrower; alveolar length of upper molar series shorter; tympanic bullae more inflated ventrally; molariform teeth smaller and lighter.
_Remarks._--One specimen from Kanab is an intergrade between _trumbullensis_ and _absonus_. The majority of its characters are with _absonus_ to which it is referred (see Hall and Davis, 1934:52). Two specimens from Escalante are intergrades between _absonus_ and _dissimilis_, but are referable to _absonus_.
_Specimens examined._--Total, 3, distributed as follows: _Garfield County_: Escalante, 5,258 ft., 2 (B. Y. U.), _Kane County_: Kanab, 4,925 ft., 1 (M. V. Z.).
_Thomomys alexandrae_ Goldman, Journ. Washington Acad. Sci., 23:464, October 15, 1933.
_Thomomys bottae alexandrae_ Benson, Univ. California Publ. Zoöl., 40:449, December 31, 1935.
_Type._--Male, adult, skin and skull, No. 250969, U. S. National Museum (Biological Surveys Collection); 5 mi. SE Rainbow Lodge, near Navajo Mountain, Coconino County, Arizona; June 16, 1933; collected by E. A. Goldman; original number 23613 (after Goldman, type not seen).
_Range._--In extreme southwestern San Juan County, Utah. Known only from Navajo Mountain, probably limited to the area enclosed on the north by the Colorado and San Juan rivers, on the east and west by Navajo and Piute canyons, respectively.