90 SaUALIDES. 



ism is particularly necessary in the economy of the 

 shark, — obliged by the law of its nature to sub- 

 sist on living animals, — which, were it not for 

 the singular provision in pointing all the teeth 

 backward, and the prickly spines in the gullet, di- 

 rected the same way, would escape almost as soon 

 as swallowed. 



The same mechanical arrangement is noticeable 

 in the throats of all the serpents : the teeth are 

 not for mastication, but solely for holding and pre- 

 venting the escape of the prey. We therefore 

 place implicit confidence in the biblical account, 

 that God created a fish, expressly to accom- 

 plish the miracle of swallowing, and subsequent- 

 ly ejecting the undutiful prophet upon the dry 

 land. 



Pliny's close observation may be inferred, from 

 a statement he makes, that the shark turns on its 

 back to bite, unless it settles over the ob- 

 ject, — an observation corroborated by succeeding 

 writers. 



The tail being a powerful organ of destruction, as 

 soon as the animal is drawn on the deck of a ves- 

 sel, the seamen usually cut it off immediately, with 

 an axe. 



When the skin is nicely manufactured, a kind of 

 leather is made, called shagreen, used in covering 

 mathematical and surgical instrument cases. 



