200 CLASS MAMMALIA. 



direction downward. The burrows are usually about twenty 

 feet from each other, and they have generally several occu- 

 pants, as seven or eight may be usually seen upon one 

 mount, where they delight to sport in fine weather. On the 

 approach of danger, they retreat to their dens; but if their 

 cause of alarm be not too close, they remain barking and 

 flourishing their tails on the edge of their holes, or sit erect 

 to reconnoitre. From their habit of burrowing, it is ex- 

 tremely difficult to take them. 



They pass the winter in a lethargic state; but lay up no 

 provisions. They protect themselves from the cold by 

 closing up the entrance of the burrows. Within their 

 retreat, they construct very neat globular cells, of fine dry 

 grass, having an aperture at the top large enough to admit 

 a finger, and so compactly formed that they may be rolled 

 about without receiving injury. 



Of its dentition and internal structure, we can add no- 

 thing ; it is therefore not possible to determine, whether it 

 belongs to the Marmots, to which (always remembering 

 that genera with single species are ever to be suspected) 

 we should be strongly inclined to refer it. 



The genus Hystrix is thus characterized. The clavicles 

 are imperfect, there are two incisive teeth in each jaw, and 

 four cheek-teeth on each side in both jaws; these have flat 

 crowns, surrounded with a line of enamel, which enters 

 more or less deeply into the external and internal edge, and 

 appears to cut the tooth into two parts ; there are also little 

 radii of enamel, which wear down by detrition ; the muzzle 

 is thick and truncated ; the lip cleft; the tongue furnished 

 with spiny scales ; the ears short and round ; the tail 

 various in the different species; the anterior feet with 

 four toes; the posterior with five, all armed with thick 

 nails. 



The spines, commonly called quills, distinguish this 



