326 ZOOLOGY. 



destruction. In some land insects, a nocturnal light is 

 supposed to be an amorous incentive; but this will 

 scarcely apply to the lowly organized medusa nor is it 

 altogether probable that their light is given them to 

 attract their minute prey; although such hypothesis 

 will apply well to the luminous species of Shark and 

 Scopelus, which I have had occasion to describe. On the 

 whole we are compelled to admit, that no very promi- 

 nent or indisputable purpose can at present be attri- 

 buted to this wonderful display. 



