LIGHT PRODUCTION IN CEPHALOPODS. 143 



"Origin" might have been enriched by many examples as start- 

 ling in their way as any of the classical ones. The complex 

 cephalopod chromatophore, the inter-playing system of exactly 

 balanced musculature with scarcely any hard skeletal parts to 

 give it support and leverage which goes to make up the arms and 

 each single sucker, the delicate adjustment between eye, sucker 

 and chromatophore through the mediation of the nervous 

 system to result in one of our most perfect demonstrations of 

 concealing coloration, the innumerable types of hectocotylus 

 often involving the most astonishing modifications in sexual 

 behavior, the amazing and still insufficiently understood mech- 

 anism of the spermatophore, the eyes, and, without attempting 

 to prolong the list further, the photogenic organs, each is in 

 its own way a triumph of adaptive development, how much so 

 we may perhaps infer to some extent from the widespread 

 occurrence of these structures in one form or another among 

 nearly all the now-surviving cephalopods. Continuing with the 

 structures last named, for instance, I think it can be truly said 

 that no other class of animals can compare with the cephalopods 

 in the complexity, diversity, beauty, brilliancy, in brief, the 

 high specialization of organs devoted to the production and utili- 

 zation of that form of energy which to our human faculties finds 

 expression as light. 



It has been said with considerable show of truth that the 

 generation of light by the plasm of animals and plants is really 

 far less to be marveled at than the transformation of their 

 energy into motion. But motion is practically a general prop- 

 erty of protoplasm in all its forms, without which it could scarcely 

 exist as living substance at all. The reason why the production 

 of organic light appears so remarkable to most of us is more 

 special: it is partly of course because of the apparent economy 

 of this light so far as the dissipation of heat energy is concerned, 

 but mainly to the average observer because of its evident highly 

 specialized adaptation to certain particular ends. 



Dubois wrote in I8Q5: 1 'The most resplendent of all animals 

 are insects, of which class the glowworm, beloved of the poets, is 

 one of the most brilliant examples." Cephalopods were scarcely 



Smithsonian Report, 1895, p. 418. 



