132 



CHAEACTERS OF VERTEBRATE ANIMALS 



South America, but also represented in the West Indies and 

 in Africa. A typical form is the Degu [Octodon degus) of Peru 

 and Chili (fig. 93). The enamel folds on the crowns of the 

 grinding teeth have a characteristic figure-of-eight pattern. 



Fig g? — The Common Dormouse {MHScardinus avellananus) 



(2) The Porcupine Family, distinguished by the possession 

 of quills, is very widely distributed, Australia being the only 

 continent from which its members are absent. All the Old 

 World forms live on the ground, as is, for example, the case 

 with the Common Porcupine [Hystrix cristatd), which inhabits 

 the Mediterranean countries, though comparatively scarce in 

 those of them which are European. The Brush-tailed Porcupine 

 {Atherura Africand) of West and Central Africa looks like a 

 spiny rat. The New World forms are distinguished by being 

 climbers. A common example is the Canadian Porcupine 

 {Erethizon dorsatus). 



None of the remaining families of the Porcupine group are 



