SERPENTS. 



391 



eye is a scaly spine or horn, which is supposed, by the ignorant natives, to be pos- 

 sessed of the most wonderful virtues. Though its home is in the hottest deserts of 

 north Africa, where it lies half buried in the sand, awaiting the arrival of its prey, it 

 can endure severe cold and prolonged hunger ; the latter, however, might be expected 

 from its habits. Specimens have been kept in confinement upwards of two years 

 without taking any nourishment, though they sloughed their skins at regular intervals, 

 showing that they were in a healthy condition. To this species has been attributed the 

 questionable honor of producing the death of Cleopatra. 



The asp, or Vipera aspis, has a wide distribution over Europe, extending north into 

 Sweden, as the only boreal poisonous reptile. The bite of this ophidian is much 



Fia. 226. — Clotlio arietans, African pu£E-adder. 



dreaded, for, though it only rarely produces death, it is very painful, often inducing 

 the victim to amputate the affected part rather than endure the pain or run the risk 

 of possible death. The viper or adder, Pelias verus, is the only venomous reptile 

 known to inhabit England, where, as has been already stated, it is often mistaken for 

 the grass-snake, which, in turn, is not infrequently mistaken for the adder. They are 

 easily distinguished, however, as the poisonous reptile has a zig-zag chain of dark spots 

 running along the back, which are not present in the innocuous form. The ground 

 color of the viper is, moreover, generally of a greenish-olive or brown, though specimens 

 of a yellow, a brick-red, or a black color have been captured. To this species, as is the 

 case with many other poisonous reptiles, the habit of swallowing or partially swallow- 



