COUES ON GEOMYS AND THOMOMYS. 247 
re-appearing by name, remained names only, with copied or compiled accounts 
attached. Professor Baird's only compilation was in the case of Thomomys 
" talpoides," which he did not claim to recognize. He examined the Phila 
delphia types of "borealis" and "townsendii," which Dr. LeConte had already 
satisfactorily located. He referred "Diplostoma bulbivorum" to the Californian 
form, remarking upon its close afriBity to T. "douglasii," and established the 
identity of "umbrinus" with the New Mexican form. He adopted as distinct 
species the T. rufescens of Maximilian and T. fulvus of Woodhouse, and added 
a new one, T. laticeps. His descriptions are like those of Richardson's in 
their minuteness and accuracy, which leave no doubt of his meaning, and the 
continual recurrence of comparative expression favors recognition of the dis 
criminations made ; but, as in the former case, they include much repetition 
of generic characters. It is a significant fact, however, that in this article 
the author omits the admirable antithetical tables he usually gives, and 
throughout seems to have rather undertaken the identification and descrip 
tion of the species currently recognized at the time, than a critical revision 
of the subject. Alluding to his lack of adequate material, he frankly charac 
terizes the article as "a very unsatisfactory account." I have only to add to 
this, that, as is well known, the tendency at the time Professor Baird's article 
was written was to push specific discriminations beyond a point now usual. 
Under such circumstances as this sketch of the history of the genus 
shows to have existed, it would be singular if some combination of currently- 
recognized species were not required. The reduction I find necessary, and 
propose to make, is after all not a violent one. Holding for the moment the 
three forms 1 shall describe as geographical races to be species and they 
would be so regarded by any one working upon a moderate number of speci 
mens the following are the only combinations required : 
BAIRD, 1857. COUES, 1875. 
1. Thomomys bulbicorus .. ~\ f 
2. Thomomys laticeps > Pacific coast region < BULBIVORCS.. 
3. Thomomys douglassii ..] \_ 
4. Thomomys f borealis. ..} f 
5. Thomomys rufescens ... > Northern Interior < TAZPOIDES .i ~ b 
6. Thomomys "talpoides".) ' [ 
7. Thomomys umbrinus ... 1 
> Southern Interior and Lower California < UMBRINCS -... 
8. Thomomys fulvus J J ^ g. -g 
