TEE CANADA PORCUPINE. 



137 



urbanity given by a captive Urson to a Mastiff that attacked him. The food of the Urson consists 

 of various vegetable substances, fruits, buds, and the young shoots and leaves of trees. In the winter it 



MEXICAN TREE PORCUPINES. 



subsists chiefly upon the bark, which it strips off the upper branches of the trees, and when it hf.s taken 

 up its abode upon a tree it stays there until the suitable bark has been consumed. As it prefers young 

 trees this operation is generally effected pretty quickly, and in this way it is estimated that a single 



