_Additional Records_: _Weber County_: Ogden, 6. _Salt Lake County_: Parleys Canyon, 1 (Bailey, 1915:114).
=Thomomys talpoides oquirrhensis= Durrant
_Thomomys talpoides oquirrhensis_ Durrant, Bull. Univ. Utah, 30 (No. 5):3, October 24, 1939.
_Type._--Male, adult, skin and skull; No. 2605, Museum of Zoölogy, University of Utah; Settlement Creek, Oquirrh Mountains, 6,500 ft., Tooele County, Utah; June 11, 1938; collected by S. D. Durrant; original number 1461.
_Range._--Known only from the Oquirrh Mountains, which are in Salt Lake, Tooele and Utah counties, Utah.
_Diagnosis._--Size medium (see measurements); ear long; tail short, claws of front feet long and slender. Color: Upper parts Buckthorn Brown, mixed with black, grading over the sides and flanks to Pinkish Buff on the ventral surface; feet white; nose grayish black; postauricular patches medium in size and black; chin and throat with varying amounts of white; proximal two-thirds of tail dark brown, distal third white. Skull: Long and slender, but relatively wide across mastoidal region; nasals long and rounded posteriorly; rostrum long and narrow; zygomatic arches weak and not widely spreading, tending to be slightly bowed out posteriorly, but in the main roughly parallel to the sides of the skull; outer margin of zygomatic arch slightly concave, and zygomatic arch dips deeply ventrad; dorsal surface of skull smooth, with weakly defined parietal crests; parietal crest nearly parallel, but bowed medially, in parietal region, and flaring widely posteriorly to pass lateral to interparietal; tympanic bullae large, truncate anteriorly and markedly inflated ventrally; upper incisors short and fairly robust.
_Comparisons._--From _Thomomys talpoides uinta_, _oquirrhensis_ may be differentiated as follows: Color: Darker throughout; postauricular patches larger and darker; ears longer and more pointed; inner margin of pinna heavily pigmented; external opening of ear smaller. Skull: Nasals rounded posteriorly rather than deeply emarginate, and less flaring distally; zygomatic arches weaker and markedly less widely spreading; pterygoid hamulae weaker; basisphenoid narrower; upper incisors shorter and wider.
For comparisons between _oquirrhensis_ and _Thomomys talpoides gracilis_, and _oquirrhensis_ and _wasatchensis_, see comparisons under those forms.