SERPENTS. 



391 



eye is a scaly spine or iiorii, wliicli is supposed, by the ignorant natives, to be jios- 

 sessed of the most wonck'rful virtin'S. Thimgh its lioinc is in tlie liottest deserts of 

 north Africa, wiiere it lies liulf buried in the sand, awaiting the ai-rival of its prey, it 

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

 from its habits. Speeimuns have lieen kejit in confinement u]iwards 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 Las been attributed the 

 questionable honor of prt)ducing the death of Cleojiatra. 



The asp, or Vipera <(spis, has a wide distribution over Europe, extending north into 

 Sweden, as the only boreal poisonous rejitile. The liite of this ophidian is much 





^'■-^:^c.^'^^_^.^... 



f IG. 226. — Clotho arietaiis, African puff-adder. 



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

 the victim to amputate the affected i)art rather than endure the paiu or run the risk 

 of possible; death. The viper or adtler, 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 alonij; 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 sjiecimens 

 of a yellow, a brick-red, or a black color have been ca]iture<l. To this species, as is the 

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



