18 THE FAUNA OF THE DEEP SEA 



The absence of any evidence obtained by accurate 

 systematic researcb, together with the consideration 

 of the physical character of the ocean bed, were quite 

 sufficient to lead scientific men of that period to 

 doubt the existence of any animal life in water deeper 

 than a few hundred fathoms. 



We now know, however, that there is a very 

 considerable fauna at enormous depths in all the 

 great oceans, and we have acquired, moreover, con- 

 siderable information concerning some of those 

 peculiar physical conditions of the abyss that fifty 

 years ago were merely matters of speculation among 

 scientific men. 



The relation between animals and their environ- 

 ment is now a question of such great interest and 

 importance that it is necessary in any description of 

 the fauna of a particular region to consider its 

 physical conditions and the influence that it may be 

 supposed to have had in producing the characteristics 

 of the fauna. 



The peculiar physical conditions of the deep seas 

 may be briefly stated to be these : It is absolutely 

 dark so far as actual sunlight is concerned, the 

 temperature is only a few degrees above freezing 

 point, the pressure is enormous, there is little or no 



