52 OUR REPTILES. 



water, whilst the viper evidently prefers a drier 

 locality. We have heard of vipers being found on 

 marshes, but are doubtful whether the creatures so 

 called were not common snakes. 



The entire length of this species is generally over 

 two feet, sometimes exceeding three feet, and rare 

 instances have been recorded, of which several occur 

 in the pages of the Zoologist, of its reaching, and 

 even exceeding, four feet. The female is usually 

 the largest. The colour of reptiles is very prone to 

 variation, but the tint of the upper surface in this 

 species is generally of a brownish-grey with a green- 

 ish tinge, sometimes nearly that of an ash stick. 

 Along the back are two parallel rows of small black 

 spots, with a series of larger blotches of black of 

 variable sizes along each side. The under surface is 

 of a dull lead-colour, sometimes mottled. The scales 

 and their arrangement, especially on the head, differ 

 from those of the viper. In the common snake the 

 head is covered by large plates, of which there are 

 three between the eyes, and those above and below 

 are arranged in pairs. The scales along the back 

 are oval and distinctly keeled, with those of the 

 sides broader, and less keeled. On the belly the 

 plates are single, extending from side to side, and 

 about one hundred and seventy in number; but 

 in this there is also variation. The under plates of 

 the tail are in pairs. Behind the head is a broad 



