TAILS 



81 



The new tail simply grows again, and no part of the 

 body breaks. 



On the contrary, one lizard has a tail set with 

 spines all around nearly as numerous as hairs (Fig. 

 40), and if this be left outside when escaping into a 

 burrow it is not a savory mouthful to the pursuer. 



Fig. 40. — Spiue-tailed lizard \^ Uromastic spinipes) aud young. 



The ancient forms of lizards often had great spines 

 on their tails wliich were very effective weapons. 

 Others had the tail flexible and flat for swimmino^ 

 purposes, as it now is in crocodilians. 



In snakes the tails taper with the body usually, 

 and thus complete the symmetry or beautiful shape, 

 but they are useful in many other respects. In the 



