A DOME BENEATH THE WATERS. 189 



care of themselves, and woe be to the intruder that 

 dares approach too near ! The male fish immediately 

 dashes at it and attacks it with the utmost ferocity ; a 

 terrible battle ensues ; the combatants swim round 

 'and round each other with the greatest rapidity, bit- 

 ing and trying to pierce each other with their spines, 

 which stand erect like sharp thorns upon their backs, 

 and with which they sometimes succeed in ripping 

 open and killing their opponents. 



When kept in glass tanks and aquariums these 

 little fish are a source of much interest and amuse- 

 ment, though, as may be supposed, it is better to let 

 them have a tank to themselves, and not to introduce 

 other and more peaceful fish to share it with them. 



There are various kinds of these fish, called, after 

 the number of spines upon their backs, three-, five-, 

 ten-, and fifteen-spined sticklebacks. The fifteen- 

 spined stickleback lives in the sea, and makes its nest 

 of seaweed or coralline. It has the same habit of 

 giiarding its eggs as the fresh-water species, and is 

 quite as quarrelsome. The threads spun by the 

 fifteen-spined stickleback resemble silk, but how the 

 fish spins them has never yet been discovered. 



A DOME BENEATH THE WATERS. 



Among all aquatic homes of man or animals, the 

 strangest and most interesting is that of the water 

 spider, who makes her house with silken walls under 



