VII A WOODLAND CODGER 203 



including many rat-like animals, small and large, 

 some belonging to North Africa, but mostly South 

 American. 



In many members of this group the hair has a 

 peculiar sharpness, with more or less intermixture 

 of stiff prickly hairs, becoming quills in the most 

 typical ; while others, as the chinchilla and coypu, 

 are noted for the extreme softness of their fur, 

 making it valuable in trade. 



The central family is that of the porcupines 

 (Hystricidae), long ago divided into two branches: 

 the synetherine, or New World arboreal porcu- 

 pines, and the hystricinine, or Old World terres- 

 trial porcupines ; but this division is made on 

 anatomical grounds, not upon difference of habitat 

 or habits, to which the classifiers are more blind 

 than is always well for the stability of their work. 

 To the former branch belong our subject and its 

 South American cousins, the tree-porcupines ; to the 

 latter, the common European porcupine. 



Of the last named (Hystrix cristatci) a brief 

 account by W. S. Dallas may be useful for pur- 

 poses of comparison with the characteristics of the 

 American form. 



"The head, shoulders, limbs, and under parts 

 are clothed with short spines intermixed with hairs 

 usually of a dusky or brownish black hue; the 

 neck is marked with a whitish collar; from the 

 back of the head and neck there arises a great 

 crest of long bristles, many of them fifteen or six- 

 teen inches in length, which can be elevated and 



