250 THE HARMONIES OF NATURE. 



rapid increase might have destroyed the balance of marine 

 existence, propagation has been providently reduced to narrower 

 limits. Thus the gaudy filefish that swim like animated gems 

 among the coral -gardens of the tropical seas, and are not only 

 able to seek a ready refuge among the dense branches of the 

 lithophytes, but whose skin is moreover covered everywhere 

 with minute spines, are far less prolific than the migratory 

 fishes; and the voracious rays and sharks, whose inordinate 

 increase would have given them a dangerous supremacy in the 

 maritime domains, bring forth but a few young at a time. 

 As the length of the newly-hatched white shark which at a 

 later period is, in size and voracity, the most formidable of all 

 the species does not exceed a few .inches, we also may be 

 sure that numbers of these young monsters are swept away 

 before they are entitled to rank among the tyrants of the deep. 

 In their double quality of predaceous and persecuted animals, 

 the fishes are well provided with those means of attack or 

 defence that are absolutely necessary for their maintenance 

 on a scene of perpetual warfare. Many of them trust to the 

 wonderful velocity of their movements ; while others, conscious 

 of inferior agility, conceal themselves in the mud or among the 

 rocks and sea-plants either to escape pursuit, like the hare, or 

 to pounce, like the falcon, upon their unsuspecting prey. In 



the ostracion and 

 lepidosteus we 

 see a solid cui- 

 rass of hexagonal 

 scales, inclosing 

 the animal in an 

 ostracion. (Tortoise Fish.) almost impreg- 



nable citadel ; while the tetrodons and diodons have the power 

 of inflating their body at pleasure, and thus raising the long 

 acute spines dispersed over their side and abdomen, in such a 

 manner as to form a defence as excellent as that of the hedge- 

 hog or porcupine. 



The little stickleback not only makes use of its dorsal spines 

 as a means of defence, but as a formidable offensive weapon ; 

 for the males are exceedingly pugnacious, and in their pigmy 

 broils use them with such fatal effect, that one occasionally rips 

 up and kills the other. 



