182 HOUSE, GARDEN, AND FIELD 



plates are arranged in bands, with flexible lines between. 

 The face is protected by a pointed shield, and even the 

 legs and tail have their share of armour. When the 

 armadillo is suddenly attacked, he closes up with a snap, 

 and nothing can harm him. Even the jaguar cannot 

 bite through his bony skin, nor tear him with his powerful 

 claws. If surprised on soft ground, the armadillo burrows 

 out of sight, and it is hard work for a man with a spade 

 to follow him. The pangolin of the East Indies, a sort 

 of first cousin to the armadillo, has the upper side of its 

 body and of its long tail covered with stiff, sharp-edged, 

 overlapping scales. When alarmed, the pangolin bends 

 himself together, and wraps his great tail about him. The 

 sharp edges of the scales now stand out, and form a com- 

 plete defence. 



The Tetrodons and Diodons (file-fishes and globe-fishes) 

 of tropical seas resemble hedgehogs in their spines, and 

 in their power of assuming a spherical shape. But there 

 is no rolling up here. The fish distends its body with 

 air, and floats at the surface of the sea, usually back 

 downwards. 



Sea-urchins furnish beautiful examples of the spherical 

 shape protected by spines. Here again there is no rolling 

 up ; the shape is unalterable by the will of the animal. 

 Globular sea-urchins, with dense calcareous armour and 

 flexibly jointed spines, inhabit the rocky shores, usually 

 well below tide-marks. Flattened species are fond of 

 burying themselves in sand. 



How does an Echinus enlarge its shell ? It cannot be 

 cast, nor changed in shape. If you break up an Echinus 

 shell, you will see how the problem is solved. The shell 

 is compound a spherical box consisting of hundreds of 

 separate pieces fitted together with the utmost nicety. 

 Running from top to bottom are five regular bands, alter- 

 nating with five others of different size and form. Each 

 of these ten bands is divided by a zigzag line running 

 along its whole length, and each half -band is again divided 



