EEPTILIA. 363 



not numerous : they include three species of snakes, namely, 

 the Adder ( Vipera berua), the Grass-snake (Trojndonotus nafrix), 

 and the Smooth Snake i^Coronella Iwcix) — and some Lizards 

 (Lacertilia), namely, the Blind-worm {Anguis frcujilis), the 

 Common Lizard (Lacerta vivlpara), the Sand Lizard [L. uijilis), 

 and the Green Lizard [L. inridis). 



The Adder (Vipera berus) can be easily told from the Grass- 

 snake. It has a broad head, and varies in colour from greenish- 

 grey to deep chestnut- brown, with a dark band of lozenge-sliaped 

 patches down the dorsal side of the body. Sometimes entire 

 black specimens may be found on the North Downs. In length 

 the adder may attain as much as thirty-two inches. The two 

 poison-fangs are well developed (fig. 204, c) : through them, by 

 a small canal in each, the poison is poured Jnto the wound they 

 cause, which never seems to bleed. Very few instances of the 

 adder bite have proved fatal, nevertheless the poison causes 

 much pain and violent inflammation and swelling in the 

 poisoned region, which may last for some considerable time. 

 Adders are particularly fond of hillsides and heathy tracts, 

 especially where the sun strikes with much warmth. They 

 look after their young for a little while. Often the young are 

 produced alive. The food of adders consists chiefly of frogs 

 and mice. Strong ammonia rubbed into the wound is one of 

 the best remedies for the bite. 



The Grass or Einged Snake (TropiJonotus natrix) (fig. 204, b) 

 is longer than the adder : they have been seen over three feet 

 in length. It is bluish in colour, with black and creamy-white 

 marks on the ventral surface, and with a yellow and black 

 band across the neck. The eggs are laid in strings in sandy and 

 dry places, and incubate by the heat of the sun ; they are also 

 often buried in leaves, which hastens their development. 



The Erown or Smooth Snake (Coronella In-m>:) is from about 

 one and a half to two feet long, brown in colour, with dark- 

 brown patches on the back and with a dark-brown head. They 

 are not very common, and feed chiefly on Lacertilia. 



The ISlind-worni or Slow-worm (Angim fiugilis) (tig. 205), 



