WEAPONS OF DEFENCE. 267 



spines of the hedgehog or porcupine. In some 

 species they are like harpoons, each being supplied 

 with a double series of strong barbs. 



The instruments can all be withdrawn into the 

 body of the animal at will, but we can easily conceive 

 that such formidable weapons being retracted into 

 its flesh would not add to the creature's comfort 

 in fact they would produce a deadly effect, were it 

 not for the following simple and beautiful contrivance. 



Each spine is furnished with a double sheath 

 composed of two blades, between which it is lodged; 

 these sheaths closing upon the sharp points of the 

 spear when the latter is drawn inwards, effectually 

 guard the surrounding flesh from injury. 



The shape of this animal is oval, the back convex, 

 while the under part presents a flat and curious 

 ribbed-like appearance. Its length varies from 

 three to five inches; specimens, however, are some- 

 times to be procured, even on our own shores, of 

 much larger dimensions. 



