GEOMYIDiE— GEOMYS 13UKSARIUS. 6J3 



Hamster du Canada, Desm., I. c. . . • 



Pseudostome a bourse, Less., I. c. 



Hiploslome brun, ]). blanche, Desm., Less., U. cc. 



Canadian Hamster, Griff., '. c. 



Goffer, Taschenmaus, Semxz, 1. c. 



Pouched Eat, Sand Eat, Camas Eat, Pocket Gopher, Sal inlander, Vui.GO. 



G a n f re or Ganffre, French (whence English "gopher", and German "gofl'or"). 



Diagnosis. — Superior incisors bisulcate, with a flue sharp groove along the 

 inner margin, and another, much larger, bisecting the remaining plane sur- 

 face. Cheek-pouches ample, extending to the shoulders. Hands, including 

 claws, longer than feet. Tail and feet hairy. Pelage soft, sleek, mole-like. 

 Color dull reddish-brown, muddy -gray or hoary beneath, the basal portion of 

 the fur plumbeous throughout (general color sometimes blackish-gray) ; fret 

 and tail, for the most part, white or colorless. Average dimensions of adult, 

 7 to 8 inches, but ranging from 6.50 to 9.00 at least ; tail, 2 or 3 inches ; fore 

 foo', including longest fore claw, about l£ inches; hind foot, including claw, 

 about \\ inches; longest fore claw, about 0.75 inch, but very variable — from 

 little over 0.50 to 1.25. 



Habitat — Valley of the Mississippi and its tributaries in a broad sense, 

 and somewhat beyond to the northward. "Canada." Not known to occur in the 

 United States west of the Rocky Mountains. Specimens examined from the 

 whole immediate valley of the Mississippi, from the State of that name to Min- 

 nesota and Dakota ; also from Texas; from the Platte, Washita, and Niobrara 

 Rivers, &c ; and from the eastern foot-hills of the Rocky Mountains of Colorado. 



In the female, there are three pairs of teats — two inguinal, near together 

 along the inside of the thighs ; and another pair, pectoral, at a considerable 

 distance. I have not been able to discover any more ; and as the same num- 

 ber and position have been found to hold in G. tuza, mexicanus, and hispidus, 

 such is probably the normal case in this genus; though in species of Thomo- 

 mys I have distinctly recognized six pairs. 



The character of the incisors demands special notice, as it is diagnostic 

 of the species. Two grooves upon each upper incisor always persist distinctly. 

 One of these is a sharp, fine line of impression, running along the inner 

 margin of the tooth, about the distance of its own width from the edge. The 

 other is a much larger, more profound, and wider sulcus, which fairly bisects 

 the remaining surface, leaving an equal plane area on either side, exclusive 

 of the small portion cut off by the fine marginal groove. This main groove 

 varies a good deal in depth and width in different specimens, and, moreover, 

 is itself sometimes sulcate ; that is to say, this excavation sometimes presents, 



