FAMILY HYSTRICID.E ; PORCUPINE. 263 



hairs. It swims with great ease, and burrows in the neighbour- 

 hood of water. It is easily domesticated ; and its manners in 

 captivity are very mild. As many as 600,000 or 800,000 skins 

 of this species are annually imported into Britain from South 

 America, chiefly from the Rio de la Plata, under the name of 

 Neutria skins. 



231. The second section of the Rodentia, in which the 

 clavicles are either absent or are imperfectly developed, altogether 

 occupies a lower place in the scale ; the animals composing it 

 being for the most part less highly organised, not capable of 

 executing so great a variety of actions, and less remarkable for 

 their instinctive propensities. It is observable that, with the 

 exception of the Porcupines and Hares, which are spread over 

 nearly the whole of the globe, almost all the very numerous 

 genera of which this section consists, are restricted to South 

 America and the West Indian Islands. The principal families 

 comprehended in it, are the HYSTRICIDJE or Porcupine tribe, 

 the CAVID.E or Guinea Pig tribe, the CHINCHILLIDJE or Chin- 

 chilla tribe, and the LEPORID.E or Hare tribe. These are separated 

 from each other chiefly by characters supplied by the teeth. In 

 the first and last only of these families, the molar teeth are 

 possessed of growing roots ; in the others, they are destitute of 

 them. The last is distinguished (as already remarked, 216), 

 by the presence of small incisors behind the great cutting-teeth ; 

 and the ChinchillidEe differ from the Cavidae, in possessing 

 clavicles. 



232. The animals properly composing the family HYSTRI- 

 CID^!, are well known under the name of Porcupines, which is 

 derived from the French porc-epin, signifying a spiny hog, a 

 designation conferred upon them on account of their heavy pig- 

 like aspect and grunting voice, and the curious spiny covering 

 which their bodies possess (Fig. 47). These spines, as already 

 explained ( 76), are nothing else than enormously developed 

 hairs. The best known species of Porcupine is the one which 

 inhabits the South of Italy, Sicily, Spain, and Barbary ; it is 



