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CHAPTER IV 



THE CHARACTERS OF THE DEEP-SEA FAUNA 



THE general characters presented by animals living 

 in deep water may be considered under several 

 headings. The most important are those that are 

 directly or indirectly related to the fact that the 

 animals live either in total darkness or in the faint 

 and probably intermittent light emitted by phos- 

 phorescent animals ; namely, the colour of the skin 

 and the peculiarities of the eyes. 



The colours of the skin of the deep-sea animals 

 vary to a very remarkable extent in the different 

 groups. It cannot be said that there is any one 

 colour at all predominant, and it is only in certain 

 classes that black, white, or dull-coloured animals are 

 more numerous than others. The colours are how- 

 ever usually very evenly distributed, and we find but 

 few examples of animals with spots, stripes, or other 

 pronounced markings. 



The majority of the fish are dark brown or black, 

 but many other colours are represented. Thus 



