THE HAUNTS OF LIFE 97 



adapted to make use of the gleams of phosphorescent 

 light. 



The Question of Origin. As to the origin of the 

 Deep-Sea fauna, the evidence points to the conclusion that 

 the abysses have been persistently colonized age after age 

 by migrants from the shore and from the ' Mud-Line'. 

 There is a marked resemblance between certain representa- 

 tives of the Deep-Sea fauna in a given region and representa- 

 tives of an adjacent shore fauna. Quite a number of Deep- 

 Sea animals have affinities with Polar animals. It is un- 

 likely that the Deep-Sea fauna was established long before 

 the Cretaceous times, and perhaps the cooling of the Poles 

 and the setting up of a bottom-movement equatorwards 

 of cold water rich in oxygen was one of the conditions of 

 the abysses becoming a home of life. The rarity of primi- 

 tive types in the Deep Sea shows that we cannot regard 

 the fauna as made up of relics of very ancient days. 



Professor Johannes Walther calls attention to the signifi- 

 cant fact that no Palaeozoic types occur in the present Deep- 

 Sea fauna. Archaic forms like Lingula (lamp-shell), Limu- 

 lus (king-crab), Nautilus, Pkurotomaria, Mytilus, Serpula, 

 and Astropecten are littoral, not abyssal. The present-day 

 Deep-Sea animals do not date back further than the 

 Triassic period, and some of them are closely related to 

 Cretaceous types. Walther works on to the interesting 

 suggestion that the enormous elevation-movements which 

 led to the Hercynian range in Europe, the Appalachians in 

 America, and Sudanese mountains in Africa were associ- 

 ated with complementary depressions which formed the 

 great abysses of the ocean. 



The Wonder of the Deep Sea. In one of his last 

 writings Herbert Spencer complained of the unreflective 



B 



