156 SIXTH RKPORT — 1836. 



slipping, as it were, from under the common integuments by a 

 longitudinal slit, and having their surface covered with short 

 hair. Cuvier, however, says of this figure, " // ny a rien de 

 semhlahle dans la H«<«re", the true form, in his opinion, being 

 that represented in the Transactions of the Berlin Academy, 

 1822-3, pi. 3, or in the Fauna Boreali-A)nencana, 18. B., 

 where the pouches, running backwards under the integuments 

 of the cheek, open extei'nally on each side of the comparatively 

 small true orifice of the mouth, producing the appearance which 

 is alluded to in the generic appellation, signifying " false", or 

 *' double mouth ". If the latter be the true form, the pouches 

 can be filled and emptied only by the fore feet, which do not 

 seem to be well calculated for such a purpose. Moreover, the 

 late Mr. Douglas, whose ability as an observer no one will 

 question, informed me that the pouches are filled from within 

 the mouth by the action of the tongue, becoming, when fully 

 distended, pendulous externally ; but when empty being re- 

 ti'acted like the inverted finger of a glove. Mr. Drummond 

 also sent me several specimens of different species from various 

 parts of the United States, some of them prepared with the 

 empty pouches folded beneath the skin of the cheeks, and others 

 with them filled and hanging down. Mr. Schoolcraft, on the 

 other hand, has given a description of a gauffre from personal 

 observation which corresponds with the view of the matter en- 

 tertained by Cuvier. To i-econcile these jarring statements, I 

 adopted both of Rafinesque's genera, geomys and diplostoma in 

 the Fauna Boreali-Americana ; but since the publication of 

 that work I have ascertained by the examination of a consider- 

 able niunber of specimens that the character of the dentition 

 is the same in all ; consequently they form but one genus, and 

 Mr. Douglas's account of the cheek-pouches I now consider as 

 well supported by the specimens I have examined. Geomys 

 Z»ore«//5 inhabits the plains of the Saskatchewan, Douglasii and 

 Inilbivorus those of the Columbia ; hursai'ius is from Canada, 

 pinetis from Georgia, talpoides from Florida, wnhrinus from 

 Louisiana, Drummondii from Texas, and mexicanus, as its 

 name imports, from Mexico. Diplostoma fusca and alba of 

 Rafinesque were brought from the Missouri; but as the spe- 

 cimens were impci'fcct and the descriptions are equally so, they 

 must be considered as doubtful*. 



* Rafinesque characterized diplostoma as differing from geomys in the total 

 absence of a tail, and in having only four toes on each foot ; but Cnvicv says 

 that his specimens showed five toes, as in geomys; and it is very probable 

 that the tails had been removed by the Indian lauUers in preparing the skins. 

 All the species that have conic under our notice had short tapering tails, 



