THE GREAT DEEPS 131 



a cylindrical stalk, so that they are fitted for 

 making the most of a dim light. 



Two answers to the question are possible. 

 The first is, that though the animals with large 

 eyes have been dredged up from the great 

 depths, and probably spend most of their time 

 there, they may sometimes migrate far enough 

 upwards to come within the sun's influence, 

 and it is only if the eyes are never used at all 

 that they tend to dwindle away. 



The second answer is, that though there is 

 no daylight, there is some light from luminescent 

 animals. Perhaps it is this uncertain light 

 which the big eyes use. 



Perhaps one of the biggest puzzles is that 

 the ordinary activities of life, such as digestion 

 and breathing, seem to go on quite smoothly in 

 the great deeps, although the conditions of life 

 are so very different from those to which the 

 shallow-water relatives of the abyssal animals 

 are accustomed. 



ORIGIN OF DEEP-SEA ANIMALS 



Where did the deep-sea animals come 

 from ? This is a good question, but we do 

 not yet know enough to be able to answer it 



