2598 



SCALED REPTILES 



longitudinal rows and forming three or four series between the eyes and the upper 

 labials. The coloration and marking vary to a certain extent individually; but 

 there is a great change in the brightness of the tints immediately after the chang- 

 ing of the skin. The puff adder is spread over nearly the whole of Africa, and is 

 everywhere dreaded from its deadly nature. Inhabiting dry and sandy places, it 

 derives its name from its habit, when angry or alarmed, of drawing in a full breath 

 and causing the body to swell visibly. Then the air is allowed to escape gradually, 

 producing as it does so a prolonged sighing or blowing sound which continues till 

 the lungs are emptied, this process being repeated so long as the provocation lasts. 



THE PUFF ADDER. 



(One-fifth natural size.) 



Usually this reptile lies half hidden in the sand, with its head fully exposed, and 

 when approached merely rises without attempting to escape, and so virulent is its 

 bite that even horses have been known to die within a few hours after being bitten. 

 The poison is used by the bushmen for their arrows, to the tips of which it is made 

 to adhere by being mingled with the viscid juice of the amaryllis. 



Next to the southern viper, or asp, no serpent was more feared by 



lpers the ancients than the Egyptian cerastes or horned viper {Cerastes 



fornutus}. As a genus, the two species are characterized by the small crescentic 



nostrils situated on the sides of the muzzle, the presence in the male and sometimes 



