Into the Depths 301 



Its own light, or seek It out by the aid of the light that 

 they emit themselves. The luminous spots or lanterns 

 of many fishes are developed in such a way that the 

 animals can use them to light their way in the dark 

 depths, and in some form.s these shining organs serve 

 as veritable searchlights. For instance, in one {/-Etho- 

 prora) the end of the snout is covered with a phos- 

 phorescent appendage that directs the light like the 

 headlight of a locomotive; another has a pair of great 

 flat eyes covering the whole top of the head, and the 

 eyes themselves are luminous. Of these predatory crea- 

 tures, many have enormous mouths and monstrous- 

 looking teeth, giving them not only a frightful, but a 

 fantastic appearance. And, indeed, some have been 

 known actually to swallow creatures larger than them- 

 selves. This seemingly impossible feat is owing to the 

 great distention that their soft tissues can effect. 

 Also, their vertebras lack specialization, and as a result 

 their bodies are elongate, showing more or less degen- 

 eration in those characters usually associated with sur- 

 face environments. 



Although, as I have stated above, the color of deep- 

 sea crustaceans is usually crimson or pink, there is much 

 variation in the range of these shades. In truth, they 

 are very curious in this respect. The blanched appear- 

 ance that we might expect of creatures living in per- 

 petual darkness, such as is known to distinguish those 

 inhabiting caves, is relatively rare. More frequently, 

 their colors, though uniform, are- vivid, and, in some 

 cases, even approaching brilliant orange. In some 

 way not understood, the red color is associated 

 with the darkness. This has been shown by experiment. 



