320 REPTILES OF THE WORLD 



an elliptical pupil. As a rule, the pattern is strong and 

 characteristic, consisting of a dark, continuous zigzag 

 band down the back ; this may be sooty black on an olive 

 or dark brown ground color, or dark brown on a grayish 

 hue. There is a row of ill-defined blotches on each side 

 and a dark bar from the eye to the neck; the abdomen 

 is usually black. A not uncommon variety is uniform, 

 velvety black. Following are the dimensions of an 

 adult female specimen: 



Total length 20 inches. 



Length of tail 2y± inches. 



Greatest diameter % of an inch. 



Width of head % of an inch. 



The distribution of the Viper over Europe is exten- 

 sive ; it apparently ranges farther from the Equator than 

 any other poisonous serpent — possibly excepting a spe- 

 cies of rattlesnake. The range is from Wales, eastward 

 throughout northern Europe, thence eastward through 

 Siberia to the island of Saghalien. In northern 

 Europe it is generally abundant; it ranges southward 

 to Northern Spain. It is more abundant than the com- 

 mon grass snake (Tropidonotus) in some parts of Eng- 

 land and Scotland. 



The Viper is a pugnacious little reptile, lying flattened 

 and glaring at an intruder, steadily hissing with each 

 inhalation and exhalation of the breath. Its biting mo- 

 tions are lightning-quick — a dart and return to the 

 original position. This action is characteristic of the 

 Viperine snakes. To say the snake strikes is to use an 

 appropriate term. As the head is launched forward 

 the jaws are opened to an extremely wide extent, the 

 fangs spring forward and literally stab the object aimed 

 for. At the instant of their penetration, there is a biting 

 movement, during which the muscles over the poison 



