ILLUMINATING THE OCEANS 



extraordinary luminous gland which they use to lure 

 their prey. This gland, possessed solely by the females, is 

 at the end of an appliance which can only be described 

 as a fishing rod. The base of the rod is firmly fixed in the 

 snout of the fish. Along the rod are two sets of muscles 

 which are used by the fish to raise and lower the luminous 

 bait. 



It is certain that the lights are often used as warning 

 signals to other fish. Some of the coelenterates, before 

 resorting to pitched battles with other sea creatures, in 

 which their weapons are their poisonous stings, use their 

 phosphorescence in this way : it not only illuminates the 

 surrounding region and enables them to see their foes, 

 but also warns away others of their kind, particularly 

 females who need to be kept out of the battles. 



According to August Brauer, who made a special study 

 of the luminescent organs of certain fish, the chin barbels 

 of certain stomiatid groups are used as light lures. The 

 barbels (slender tactile appendages around the mouth) 

 are very diversified. Some are whip-like, some tassel- 

 shaped, and the luminous organs are also of many kinds. 

 Some have bulbs attached, which light up, others have 

 their luminous organs within the barbels; others again 

 have luminous traceries besides bulbs. 



Brauer believed that many fishes having light organs 

 arranged in systematic groups use their light organs in 

 patterns to identify themselves to other creatures of their 

 own kind — signalling, in fact, in codes known only to the 

 members of the particular species. Such manoeuvres 

 would have special significance in the breeding season. 

 Such signals may also be used to signal information 

 regarding food to other fishes — the finding of food at a 

 distance being of vital importance to deep-sea fishes. 



Astronomical research had a start of thousands of 

 years over oceanic investigation for men had been 

 studying the stars for centuries, and had learned how to 

 interpret the light signals from suns separated from our 



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