266 THE DEEP-SEA CRUSTACEA 



of the deep-sea fishes. Their colours are not dull or 

 obscure, indeed they are usually very vivid ; but they 

 are uniformly laid on, and there is the same paucity 

 of spots and stripes and variegated patterns. Of the 

 Indian species whose living colours have been noted, 

 27 per cent, are some decided shade of red, 22 per 

 cent, are some shade of pink, and 22 per cent, are 

 orange or yellow ; a few are brown, a few purple, a 

 few are cream-coloured or grey, and a few quite white ; 

 but in only 17 per cent, can any sort of spots or 

 stripes be made out, and even then the patterns are very 

 simple ones, composed of red and white, or orange and 

 white, or red and orange. Never do we see those 

 freaks of colour, or those labyrinthine mottlings and 

 dapplings, that excite our curiosity when handling the 

 crabs and shrimps of the reefs, and this, I think, is a 

 fact which has not always been adequately considered 

 in our endless discussions on warning and protective 

 colouration. In several cases where the adult is 

 red or orange, the unhatched young are blue or 

 peagreen, which seems to show that the red and 

 the orange uniforms of the nether waters have been 

 brought about, probably by natural selection, since 

 the exodus into the abysses, and must therefore be of 

 some service. 



That at certain depths below the surface there 

 must be some peculiarity about the supply of oxygen 

 is indicated by the facts that in many of the deep-sea 



