12 DEEP SEA FISHES. 



if it docs not make an addition to the supply needed for tlie support of life. 

 In fresh condition the fishes and other animals secured at great depths, 

 are tinted with pale greenish to pale yellowish green, or, somewhat rarely, 

 to pale bluish. On Plates A to N of the illustrations herewith, the colors 

 were taken by Mr. Westergren and Professor Agassiz from the fresh speci- 

 men, before it was placed in alcohol. The pale greenish tint is seen to 

 affect even such as become intense black when placed in the preserving 

 liquids, Plates B and D, and Plate F, figures 1 and 3. That the abyssal 

 light is of a pale greenish color is evident from the colors of the animals 

 living within it; this proof is not at all confined to the coloration of the 

 fishes, it obtains throughout the bathybial fiiuna. The harmony of colors 

 between the creatures of the depths and their surroundings is paralleled 

 by that obtaining between the ashy gray inhabitants of the desert and 

 the arid wastes in which they live, or between the white in pelage and 

 plumage in the Arctic fauna and in its snowy enviromnent. From the 

 general coloration of the animals of a particular region the zoologist may 

 determine the character of the light by which it has been modified. Deep 

 sea investigation has established the fnct that life is pretty generally 

 distributed on the ocean bed. From this it would appear that similarly 

 bathybial light obtains nearly everywhere in the abysses. Probably the 

 light of different localities varies in intensity since undoubtedly there are 

 sections of the bottom that are more thinly clad with sedimentary deposits 

 of organic origin, and consequently lacking in amount and activity of 

 chemical interchange, or for other and various reasons not as well adapted 

 for the existence of animal life. 



The general greenish tint in the coloration is assimilative and occulta- 

 tive, as it renders the bearer like his surroundings and as it hides or con- 

 ceals him. It is protective to the prey when it conceals the latter and 

 destructive to it when the enemy is rendered invisible. As all the deep 

 sea animals are predaceous the tint is helpful to the individual as it hides 

 the latter from the enemy or the prey, and harmful as it increases the 

 difficulty in discovering and securing the food. The story concerning the 

 light at the bottom of the ocean is the same from whatever class of animals 

 it is drawn. On the green mud and ooze the light is greenish. 



The lower belt of light, like that at the surface, is inhabited by multitudes 

 of species, represented by myriads of individuals. Between the two belts, the 

 upper and the lowei', there apparently is a belt of darkness, the Azoic belt of 



