46 LIVING LIGHTS. 



The highest forms of the Mollusca, the Cephalopods, cuttle- 

 fishes, are probably at times luminous. I have noticed what 

 I presumed was a delicate, sensitive, luminous glow about an 

 Octopus in a semi-darkened tank, but I am not satisfied to 

 make the statement as fact. These forms are so remarkable 

 for the waves of color that pass over them, and which seem to 

 make them transparent, that one could readily be deceived. 



The little Cranchia (Plate IV., Fig. 2) is a light-giver, its 

 phosphorescence having been distinctly observed. It is an 

 ally of the giant squids, which have been found fifty-five 

 feet in length, and which, if luminous like their pygmy rela- 

 tive, would present a marvellous spectacle, darting veritable 

 living arrows through the depths of the sea. 



Giglioli refers to the phosphorescence of Loligo saggitatus> 

 and to that of several small Octopods observed by him at 

 Callao and Valparaiso. Their bodies gave out a pale whitish 

 light, uniformly distributed. 



