i] THE CATEGORIES OF LIFE 17 



at the same level as itself. The colour is usually a 

 monochrome a black or dark red: in the deep, in 

 the absence of red light, such a coloured fish would 

 appear black ; if indeed one can speak at all of colour 

 in such surroundings. 



The great majority of abyssal animals are phos- 

 phorescent : they possess luminous organs similar to 

 eyes in structure, and often the fishes of moderately 

 deep water have rows of such ocelli along their sides. 

 Sometimes deep-sea animals secrete a sort of phos- 

 phorescent slime. Why they should produce light it 

 is hard to guess : we must remember that it is only 

 to our eyes that they appear luminous. Very strange 

 indeed would be the appearance of these animals if 

 we could see them in the deep. In the absolute 

 darkness of the abyss they would appear as ghostly 

 silver-blue shapes glimmering like an electric lamp 

 through dense fog on a dark moonless night. Of 

 all the characters of the deep-sea fauna this almost 

 universal phosphorescence is the strangest. 



All the animals and plants which we have so far 

 examined belong to the category of life called the 

 Benthos a collective term applied to those organisms 

 living at the sea-bottom attached to stones or 

 other fixed objects; or burrowing in the sand or 

 mud ; and which may also be extended so as to include 

 all those animals which, though free to move about, 

 0>v? sluggish and inert, and which frequent only a 



