ADAPTATIONS 



297 



the squirrel, has a similar armature of quills. The armadillo 

 of the tropics has movable shields, and when it withdraws its 



PIG. 1(55. Flying fishes. (The upper one a species of Cypselurus^ the lower of EXOCM- 

 tus.) These fishes escape from their enemies by leaping into the air and sailing 

 or "flying" long distances. 



head (which is also defended by a bony shield) it is as well 

 protected as a turtle. 



FIG. 166. The horned toad(P/irynosoma blainmttei). The spiny covering repels many 



enemies. 



Special organs for defense of this nature are rare among 

 birds, but numerous among reptiles. The turtles are all 



