82 



STORY OF THE REPTILES 



sea-snakes (Fig. 41) they are flat and fringed like those 

 of eels, and they are thus the means of swimming. 

 In the land-snakes, tails are helpfnl in springing and 

 mnning. Our " spreadhead " {Heterodon) sometimes 

 makes great leaps down-hill by this means, and our 



Fig. 41. — Sea-snake {SydrophU cyanodnda). 



common " blue-racer " (blaoksnake) can erect its body 

 half its length and run rather rapidly on what must 

 be mainly the tail. All the tree-haunting and the 

 constricting, or crushing snakes, use the tail to cling 

 with, and to aid them in climbing and anchoring 

 themselves while crushing or holding their prey. 

 The whip-snakes (Fig. 42) and other tree-snakes have 

 tails that are longer than the body, wherewith they 



