CHARACTERS OF SOMIO HYSTfelCOMORPIl RODENTS 



375 



genera, such as Hi/strix, Atherura, Erethizon, Coendu, Cajrromys, 

 ('a'logenys, Cavia, JJolichoiis, and Ctenodactijlus, they are sepa- 

 rated, although capable of being made to meet in the middle 



Text-iieure 5. 



A. Side view of head of Coelogenys imca, the outline of the external cheek- 



pouch dotted in ; o, its orifice. 



B. Transverse section of the head of the same anterior to the molar teeth, the 



internal cheek-pouch on the left of the figure distended ; o, orifice of 

 external cheek-pouch ; t, tongue ; bony tissue dotted. 



line, but in Ctenomys, Myocastor, Chinchilla, and Lagostomus they 

 are fused across the palate anteriorly, although partially separated 

 posteriorly. 



