POISON-SNAKES. 209 



in general bold and fierce, rearing up themselves, 

 and with sparkling eyes advancing resolutely to 

 the combat, instead of retreating from the foe, 

 sometimes springing with great agility on an in- 

 truder to inflict the fatal stroke. The Najas or 

 Hooded Snakes of Africa and India, Dr. Smith 

 describes as always ready for fight, advancing, 

 when their haunts are invaded, upon the in- 

 truder with the head and forepart of the body 

 almost perpendicular, the neck expanded, and an 

 expression sufficiently indicative of the malignant 

 purpose they have in view : nor does the retreat 

 of their enemy always put a stop to their advance. 

 An officer of the Cape Corps, worthy of implicit 

 credence, assured Dr. Smith that he had been 

 chased twice round a waggon by an enraged Naja,' 

 and was delivered only by a Hottentot, who dis- 

 abled the savage reptile by a blow with a long 

 stick.* Some species, as the Horned Vipers 

 {Cerastes), will neither remove to avoid danger, 

 however imminent, nor give any indication of 

 their presence, until actually trodden on by the 

 unwary foot, when the sudden injection of the 

 deadly poison tells the intruder of his fate. 

 Others, as the Rattlesnakes {Crotalus), -^ow the ap- 

 proach of danger, give warning by agitating a 

 series of horny cells, loosely articulated within 

 each other, with which the extremity of the tail 

 is furnished, and thus often permit the avoidance 

 of their deadly stroke. 



Besides the important distinction of this Family 

 of Serpents, which is derived from the form and 

 structure of their poison-fangs, they are for the 

 most part marked by the large size and great 



* " Zoolology of South Africa." 



P 



