160 THE STORY OF REPTILE LIFE. 



enemies are warned off, and thereby the snake is 

 saved the expenditure of poison which is used 

 only for the slaughter of victims for food, or the 

 purposes of self-defence when hard pressed. 



The Cobras effect the same end by dilating 

 the neck. This is done through the agency of 

 the ribs in this region, which are raised so as to 

 expand the skin into a broad shield, sometimes 

 described as a "hood," and thereby giving a 

 terribly formidable appearance to the infuriated 

 animal. In some species the back of this shield 

 is adorned with a curious pattern described by 

 some as "spectacle pattern," by others as "eye- 

 like markings," and these are supposed to add to 

 the terrifying aspect. It is difficult to see, how- 

 ever, how this can be, since they are, from their 

 position, hidden from the view of the creature 

 for whose benefit the display is made. 



In the foregoing cases the animals when at 

 rest are quite inconspicuously coloured, and in 

 no way court attention : but the North American 

 lizard known as the Gila-monster (Heloderma 

 suspectuin) behaves in a quite different manner. 

 About two feet long, and clad in what may be 

 likened to a " blazer " of black and orange 

 arranged in rings, this creature, though more 

 or less careful to conceal its very obtrusively 

 coloured carcase, makes no effort, when dis- 

 covered, to escape danger by flight. This 

 insolent confidence is apparently begotten by the 

 consciousness of power in the possession of 

 poison fangs. It is the only known poisonous 

 lizard. Like the poisonous snake, the death- 

 dealing fangs are grooved, and down these the 





