Thomomys talpoides bulbivorus, using the name umbrinus for the animals of only southern Utah (Coues, 1877:627, 628). The two names Thomomys bottae and Thomomys talpoides, now applicable to gophers in Utah, were synonomized under the name Thomomys talpoides bulbivorus by Coues (1875:256; 1877:627). After this beginning only three other papers, all by J. A. Allen, appeared in the next twenty years. They were reports on collections of mammals made by Walter W. Granger and Charles P. Rowley. One of these contained the description of Thomomys aureus. Likewise, in the ensuing twenty years there were only three papers, one in 1901 by C. Hart Merriam in which he described Thomomys uinta, one by Allen (1905:119), and Vernon Bailey's (1915) "Revision of the pocket gophers of the genus Thomomys" in which he summarized the information then available on these animals within the state. Barnes (1922 and 1927) reprinted the information summarized by Bailey. Since 1927 approximately twenty-five papers, mostly taxonomic, have been published in which reference is made to Utah gophers, and especially since 1930 much information has been accumulated about the distribution and speciation of this genus within the state.

Specimens to the number of 1,045 have been available for this study. Whereas Bailey (loc. cit.) listed only four kinds belonging to four different species, thirty-five kinds are now known from Utah. Seven of these are herein described as new. The thirty-five kinds are found to belong to only two instead of four full species.

Inasmuch as the literature is scattered and since names have been applied in different ways at different times, I have attempted to give a synonomy as complete as possible for each form found within the state.

The bibliographies of Hayward (1936 and 1941) and Miller's (1924) "List of North American mammals" have been of great use.

Capitalized color terms in the accounts are after Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912.

In the lists of specimens examined, the localities are listed by counties from west to east, beginning at the northwestern corner of the state, and within each county from north to south. When two localities are on the same latitude, the westernmost is listed first.

FIG. 1. Map showing the distribution of species and subspecies of pocket gophers in Utah.

Genus Thomomys Wied

All pocket gophers of Utah belong to the genus Thomomys. There are only two species within the state, Thomomys bottae with twenty-four subspecies and Thomomys talpoides with eleven subspecies.

Due to marked mutational capacities and ready response to environmental pressures and sedentary habits, pocket gophers differentiate readily into numerous subspecies. It is well known