148 HABITS AND INSTINCTS OP ANIHALS. CHAP. V. 



But the highest development of this species of defence 

 is seen among the branchiostegous fishes, or order which 

 we have denominated as the cheloniform fishes, be- 

 cause they represent the tortoises and hedgehogs. The 

 genus Diodon has the body completely covered with 

 long acute spines, which stand out in every direction ; 

 these are sometimes so sharp, that they can be com- 

 pared to nothing so well as to those on the hedge- 

 hog or the porcupine. Nor do we conceive that these 

 fish can be handled, by any possibility, when they are 

 alive. In the genus Tetrodon, the belly, alone, is 

 prickly, and this part is capable of being inflated to a 

 very large size. In Ostracion, and several other genera, 

 we have a perfect representation of the armorial co- 

 vering of the cheloniform reptiles : the whole body is 

 enveloped in a bony coat, or covered with hexagonal 

 scales, the sides of which fit into each other com- 

 pactly, and thus protect the fish even from the teeth of 

 ordinary foes. 



(167.) There are several genera where the snout is 

 elongated either into a long pointed bone destitute of 

 spines, or into a flat process armed on each side with 

 formidable tooth-like spines resembling teeth. Both 

 these offensive weapons are possessed by fish of a 

 gigantic size, which, from their resemblance in other 

 respects to the sharks, lead us to believe they are alto- 

 gether rapacious. The first is the sword-fish (fig. 48.), 



which frequently grows to near twenty feet long. It is a 

 most powerful fish, which frequently attacks whales : so 

 blind is its headstrong fury, that it will pierce the sides 

 of ships with its sword-like snout, probably mistaking 

 the vessel for some huge monster of the deep. A part 

 of the bottom of a large East Indiaman, with the 



