Ill 



CHAPTER II. 



EMISSION OF LIGHT BY INFERIOR ORGANISMS. 

 PHOSPHORESCENCE OF THE SEA. 



I SHALL now enter upon the subject of Phosphoric 

 Animals; i.e. of the phenomenon of phosphorescence 

 in living animal organisms. And in the first place 

 I shall draw attention to a curious fact. With the 

 exception of a few more or less doubtful cases, to 

 which I shall allude at the end of this part of my 

 work, the faculty of producing light seems, in the 

 animal world, to cease with the class of insects. 

 But, on the other hand, from insects downwards, 

 there is scarcely a section of the animal world but 

 which furnishes us with some self-luminous beings. 

 Thus decided cases of phosphorescence have been 

 and are frequently observed, in Infusoria, Rhizo- 

 podes, Polypes, Echinoderms, Annelides, Medusae, 

 Tunicata, MollusJcs, Crustaceans, Myriapodes, and 

 Insects. 



It would indeed require volumes to describe 

 each luminous animal belonging to these numer- 

 ous tribes. I shall not attempt it here, but I 



