462 THE SNAKES OF SOUTH AFRICA. 
The Grass and Sand Snake, when alarmed, glide off over the stunted 
herbage and grass with quick undulating motions. So quick are the 
movements that, to the eye, they seem to be bowling along like a hoop. 
Colonists know these as Whip Snakes. 
When a Puff Adder is about to strike he withdraws his head and 
bunches up his body. He can propel himself the full length of his body. 
Fic. 155.—Three great chums—a Black Mole Snake, a baby Python, and a baby boy. 
Puff Adders do not strike backwards. In the act of striking they throw 
the head well back, then forwards or sideways. 
There is no such reptile as a Two-headed Snake. People often call 
the blind Burrowing Snake (Typhlops), a two-headed snake because of its 
blunt tail, which has the appearance of a head. 
