COUES ON GEOMYS AND THOMOMYS. 219 
difficulty of getting material to work upon on this family, though the animals 
fairly swarm in certain regions, becoming a serious hinderance to agriculture. 
There is another point to be considered here : the shapelessness of the species, 
so to speak, with the looseness and distensibility of the skin, renders them 
peculiarly susceptible of atrocious taxidermy, with the result of scarcely 
leaving a hint of their actual appearance and true dimensions. One result 
of all this is that a mass of pointless, if not erroneous, descriptions and con 
flicting accounts forms a large part of the written history of the species. 
There appears to have been an unusually large amount of compilation done 
in this group; more than half of everything extant upon the subject is of this 
character.* The ' systematic'' accounts given by Fischer, Schinz, Wagner, 
Giebel, and some others that might be named, are simply worthless for any 
practical purpose. The special papers upon the subject are so few that it 
was hot thought necessary to enumerate them. Aside from the descriptions 
of "new species" which it is necessary to examine, the authorities which 
need be consulted are very few. Waterhouse's and Brandt's articles ; espe 
cially Richardson's, in the Fauna Boreali- Americana ; LeConte's monographic 
sketch of the family ; and Baird's later, more elaborate, memoir, with Audu- 
bon's and Bachman's figures, represent the gist of the matter. The synonymy 
collated in this paper is believed to represent very nearly all the literature 
of the subject. 
It is not within the scope of the present article to treat fully of the 
characters of the family. I confine myself here almost entirely to the deter 
mination of the species and their full description, with the necessary biblio 
graphical matter. The number of species I find to have been, much as usual, 
largely overstated. This is particularly the case in the genus Thomomys, 
where the three recognizable races of the single known species have been 
described as a dozen distinct species, and been referred to half as many 
different genera. Most late authors recognize at least six or eight species 
of the genus. Gcomys makes out a better case ; out of the seven species 
admitted by Baird, five are unquestionably valid. It is very curious and 
interesting to note how differently Geomys and Thomomys have become differ 
entiated into species. The former genus has developed into at least five 
* Cf. the synonymy of Thomomys talpoides et off. in tbe following pages. 
