640 OPHIDIA CHAP 



to conceal the creature when it is lying on sandy and stony 

 ground ; the under parts are yellowish white. The Puff Adder 

 reaches a length of 4, or very rarely 5 feet, ranging all over 

 Africa, except the north coast, and extending into Southern 

 Arabia. It is very slow, and trusts to not being discovered when 

 lying in the dry grass ; when approached it inflates the body 

 and hisses loudly with a puffing sound, watches the enemy with 

 raised and characteristically bent head and neck; but it bites 

 only when actually touched or attacked. The effect of the bite 

 is very dangerous. Its prey consists chiefly of small mammals, 

 which are hunted during the night. 



B. (Echidna) nasicornis, of Tropical West Africa, has two or 

 three enlarged scales above the supranasals ; they stand upon 

 erectile tissue so as to form horn-like elevations. This " Nose- 

 horned Viper " grows to a length of 4 feet, and is rather prettily 

 marked ; the ground-colour is purplish or reddish brown, with a 

 vertebral series of large, pale, dark-edged spots and oblique 

 crosses. The young are at birth as much as one foot in length, 

 and are very tastefully coloured. 



Cerastes and Echis prefer to burrow in sand. The lateral 

 scales are smaller than the dorsals, and arranged obliquely with 

 serrated keels, so that the snakes can cover themselves with sand 

 by lateral shovelling motions of the sides of the body. 



Cerastes cornutus, the " Horned Viper" of North-Eastern Africa, 

 from Algeria to Arabia, extending also into Palestine, has the 

 sides of the ventral scales bent angularly, with an obtuse keel on 

 either side. Above each eye stands a large horny, spiky scale. 

 The upper parts are pale yellowish brown, mostly with dark 

 spots arranged in several longitudinal rows. The under parts are 

 white. This, or perhaps C. vipera, which has no horns, is 

 supposed to be the species which has become famous through the 

 suicide of Cleopatra. 



About twenty years ago a number of " Horned Vipers " were 

 brought to the Zoological Gardens of London, and attracted 

 attention by their unusually long horns. It was found that 

 some wily Egyptian snake-catcher had tried to manufacture a 

 new species by taking specimens of the hornless C. vipera and 

 inserting a pair of hedgehog's spines, pushing them upwards 

 through the mouth. 



The " Horned Viper " attains a length of two feet and a half. 



