FAUNA AMERICANA. 121 



Order GLIRES, Gnmcers. 



Glires, Linn. Rosores, Storr. 



Char. Two large incisors in each jaw, sepa- 

 rated from tlie molars by a vacant space. No 

 canine teeth ; molars sometimes compound, with 

 flat crowns ; sometimes with blunt tubercles. Ex- 

 tremities terminated by a variable number of 

 toes furnished with claws. Thumb sometimes 

 rudimentary or wanting, never opposable to the 

 fingers. Mammae varying in number; orbits not 

 separate from the temporal fossae ; zj^gomatic pro- 

 cesses moderately arched, thin and curved infe- 

 riorh^ 



Inferior jaw articulated by a longitudinal con- 

 dyle ; posterior extremities generally longer than 

 the anterior; stomach simple; intestines long; 

 coecum voluminous when it exists. 



Nourishment, purely vegetable in those species 

 which have compound molars with flat crowns; 

 mixed with animal substances in those which have 

 simple molars with tubercular crowns. 



Habit. Generally nocturnal and timid; tritu- 

 rating their food with their molars after having 

 torn it with their long incisors, which have angu- 

 lar summits, and are produced from their roots as 

 they are worn at the points. 



Inhabit both the old and new continents ; not 

 found in the south-sea islands. 



16 



