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CHAPTER II. 
EMISSION OF LIGHT BY INFERIOR ORGANISMS. 
PHOSPHORESCENCE OF THE SEA. 
I sHALL now enter upon the subject of Phosphoric 
Animals; 7.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 hght seems, in the 
animal world, to cease with the class of msects. 
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, Meduse, 
Tunicata, Mollusks, Crustaceans, Myriapodes, and 
Insects. 
It would indeed require volumes to describe 
each luminous animal belonging to these numer- 
eus tribes. I shall not attempt it here, but I 
