Feb. 191 2. Mammals of Illinois and Wisconsin — Cory. 239 



Family GEOMYID.^. Pocket Gophers. 



The Geomyidce are a family of fossorial or burrowing Rodents com- 

 monly known as Pocket Gophers, which are restricted, so far as known, 

 to North and Central America. They are characterized by the greatly 

 developed claws of the fore feet, small eyes and ears and external 

 cheek pouches lined with fur, which open on the sides of the face. 

 Nine genera, three of which occur in the United States, and more than 

 100 species and subspecies are recognized, but only one genus and a 

 single species occur within our limits. 



Genus GEOMYS Rafinesque. 



Geomys Rafinesque, Amer. Monthly Mag., II, 1S17, p. 45. Type 

 Geo my s pinetis Rafinesque. 



Upper incisors with two grooves (bisul- 

 cate), a deep one in the middle and much 

 smaller and narrower one near the inner 

 edge; first and second upper molars with 

 posterior enamel plate; infraorbital foramen 

 confined to lower portion of maxilla; auditory 

 meatus much elongated and tubular, opening 

 between the mastoid process of the squamosal 

 and posterior root of zygoma*; crowns of 

 cheek teeth with transverse enamel loops, 

 a single loop on each molar and two on the premolar; claws of fore 

 feet much elongated; external cheek pouches large, opening on sides 

 of face; eyes small; tail thick, much shorter than the body, and the 

 tenninal portion scantily haired; ears very small. 



Dental formula: I. ^^, C.^^, Pm. ^— , M. ^^=20. 

 i-i 0-0 i-i 3-3 



Front view showing cheek 



pouches and grooved 



upper incisors. 



Geomys bursarius (Shaw). 

 Pocket Gopher. 



Mus bursarius Shaw, Trans. Linn. Soc. Lond., V, 1800, p. 227. 



Geomys ? bursarius Richardson, Fauna Bor. Amer., I, 1829, p. 203. 



Geomys bursarius Lapham, Trans. Wis. State Agr. Soc, II, 1852 (1853), p. 340 (Wis- 

 consin). Kennicott, Trans. 111. State Agr. Soc, -I, 1853-54 (1855), p. 580 

 (Cook Co., Illinois). lb., Agr. Rept. for 1857, U. S. Patent Office Rept., 1858, 



*See Illustration, p. 96. 



