Key to the Rodentia
           
 
 Hind feet webbed; greatest length of skull usually more than 100 mm (except in muskrat, with skull less than 30 mm)
    Hind feet not webbed; greatest length of skull usually less than 100 mm, or if 100 mm, then infraorbital foramen very large (Fig. 27a)    
           
Artiodactyla
 - 
Carnivora
 - 
Chiroptera
 - 
Didelphimorphia
 - 
Insectivora
 - 
Lagomorpha
 - 
Rodentia
 - 
Xenarthra
Scientific Names - Common Names