THE DUCKBILL. 3f>7 



overshadowing grasses and drooping herbs that even the keenest 

 inspection frequently fails to detect it. The burrow itself ex- 

 tends in numerous curves and windings to a length of thirty or 

 forty feet, and at its upper extremity is placed the nest, an 

 excavation of a somewhat oval form, much broader than the 

 width of the burrow, and well supplied with dry weeds and 

 grasses, upon which the young ma-y rest. 



Burrow of the Duckbill. 



Most of the mammalia whom Nature has clothed with 

 spines or strong bony scales, increase the efficiency of their 

 armour by the faculty of rolling themselves up into a ball, and 

 thus opposing on all sides to the enemy a forest of spears or an 

 impenetrable coat-of-mail. Contracting the strong muscular 

 fibres with which its skin is interwoven, the hedgehog, when 

 molested, presents nothing but its prickles to the foe, and the 

 more the animal is irritated and alarmed the more firmly 

 does it contract itself, and the more stiff and strong does 

 its bristly panoply become. Thus rolled up, it patiently waits 



