Among named races of _Thomomys talpoides_, _parowanensis_ most closely resembles _levis_, the race nearest geographically to the east, but differs from _levis_ as follows: Size larger. Skull: Longer and wider; rostrum and nasals longer; interparietal quadrangular as opposed to roughly elliptical; upper incisors longer.
For comparisons with _Thomomys talpoides moorei_ and _wasatchensis_ see accounts of those forms.
_Remarks._--The mountains of south central Utah are inhabited by pocket gophers that have been designated as _Thomomys talpoides parowanensis_ and _T. t. levis_ by Goldman (1938:334, 336). They are nearly indistinguishable in color and each is variable in cranial details. The diagnostic characters of each form occasionally appear, in varying degrees, throughout the range of the other. The Sevier River Valley separates the ranges ascribed to these two forms. This valley is inhabited by pocket gophers that belong to a different species, _Thomomys bottae_. The ranges of these two races of _talpoides_ converge southward at the headwaters of the Sevier River. Specimens of _parowanensis_ from the northern limits of its range from the Beaver Mountains in eastern Beaver County and those of _levis_ from the northern limits of its range in the Fish Lake Mountains are readily distinguishable from each other. As the ranges converge to the southward, there is progressively more intergradation. The type locality of _parowanensis_ is located in the southern part of its range, while that of _levis_ is in the extreme northern part of its range. Therefore, due to the convergence of the two ranges at the south, the specimens from localities near the type locality of _parowanensis_ show the greatest amount of intergradation, if we regard specimens of _parowanensis_ from the type locality as typical of the race. Four specimens from Webster Flat, sixteen miles east of Cedar City, Iron County, and three from Duck Creek, Cedar Mountains, Kane County could equally well be assigned to either _levis_ or _parowanensis_.
_Specimens examined._--Total, 24, distributed as follows: _Beaver County_: Britts Meadows, Beaver Mountains, 8,500 ft., 7 (3, M. V. Z.; 2, U. S. N. M.; 2, C. M.); Puffer Lake, Beaver Mountains, 1 (U. S. N. M.); Kents Lake, Beaver Mountains, 1 (R. H.). _Iron County_: Lava Beds, 3-1/2 mi. SW Panquitch Lake, 1 (C. M.); Brian Head, Parowan Mountains, 2 (1, U. S. N. M.; 1, C. M.); Webster Flat, 16 mi. E Cedar City, 4; Bear Valley, 2 mi. E B. V. Ranger Station, 1 (R. H.). _Garfield County_: 1/4 mi. W Sunset Point, Bryce National Park, 8,000 ft., 1 (M. V. Z.). _Kane County_: Navajo Lake, 3 (R. H.); Duck Creek, Cedar Mountains, 9,000 ft., 3 (1, R. H.).