134 



NATURAL HISTORY. 



covered with long, hollow, pointed quills, whilst in all cases great numbers of spines and stift 

 bristles are mixed with the hair. The form of the skull in these animals is distinctive. 



It is ovate, the cranial portion being more or less inflated 

 by air-cavities in the bones, and the facial portion short, but 

 the occipital or hinder surface is usually nearly perpendicular ; 

 the malar portion of the zygoma has no angular process as in 

 the preceding family ; the molar teeth are four in number on 

 each side in each jaw ; and the limbs are about equal in 

 development. The incisor teeth are large and powerful. With 

 regard to the development of the tail there are considerable 

 differences, some species having that organ quite short, while 

 in others it is of moderate length, or long and sometimes pre- 

 hensile. 



The Porcupines fall readily into two distinct groups (sub- 

 families) characterised by structure, habits, and geographical 

 distribution. In the strictly terrestrial species, or True Por- 

 cupines (HYSTRICIN.E), which inhabit the warmer parts of the eastern hemisphere, the skull is rather 

 more elongated than in the others ; the front margin of the orbit is over the third molar ; the molars are 



SKULL OF THE PORCUPINE. 



COMMON PORCUPINE. 



rootless when young, but become closed after a time, and the clavicles are imperfect. The upper lip 

 is furrowed ; the tail, which may be either long or short, is never prehensile ; the soles of the feet are 

 smooth ; and the female has six teats. 



The arboreal species (SPHINGURIN.E), which are all American, have the skull peculiarly short, the 

 front margin of the oi*bit over the first molar, the molars always rooted, and the clavicles perfect. The 

 upper lip is not furrowed ; the tail is moderate or long, and generally prehensile ; the soles of the feet 

 are covered with wart-like tubercles ; and the female has only four teats. 



The COMMON PORCUPINE (Hystrix cristata) may serve as a characteristic and well - known 

 example of the first of these two groups. It is an inhabitant of the Mediterranean region, occurring 

 in most parts of North Africa, and extending as far southwards as the Gambia and Soudan; in Southern 

 Europe it is abundant in Italy, Sicily, and Greece. It measures about twenty-seven or twenty-eight 

 inches in length to the root of the tail, which is about four inches long. The head, shoulders, limbs, 

 and under parts are clothed with short spines intermixed with hairs usually of a dusky or brownish- 



