54 THE FAUNA OF THE DEEP SEA 



the problem of the origin of this fauna presented 

 itself. 



Whence came the curious creatures that live 

 mostly in total darkness and can sustain without 

 injury to their delicate and complicated organisation 

 the enormous pressure of the great depths ? Are 

 they the remnants of the fauna of shallow prehistoric 

 seas that have reached their present position by the 

 gradual sinking of the ocean basins ? Or, are we to 

 look upon the abysmal region as the nursery of 

 the marine fauna, the place whence the population 

 of the shallow waters was derived ? Neither of these 

 answers is supported by the facts with which we 

 are now well acquainted. The fauna of the abysmal 

 region does not show a close resemblance to that of 

 any of the past epochs as revealed to us by geology, 

 nor are we justified in assuming without much 

 stronger evidence than we now possess, that the 

 oceans have undergone any such great depression as 

 this first theory presupposes. 



Nor can we consider for a moment that the abyss 

 was the original source of the shallow-water fauna ; 

 for not only do we find but few types that can be 

 considered to be, in any sense of the word, ancestral 

 in character ; but on the contrary most of the animals 



