58 Walther — Origin and Peopling of the Deep Sea. 



rare or very frail. Some are blind, others distinguished by 

 telescopic eves or wonderful concave mirror-like sight organs. 

 Many live on decaying deep sea ooze and have therefore lost 

 their organs for the mastication of food, others are robbers 

 with Btrongly developed jaws. Many forms show wonderful 

 contrivances for the care of the young, while others seem to 

 multiply with extraordinary rapidity ; but almost all are pro- 

 vided with phosphorescent, light organs which unite with their 

 gay, soft radiance, that in some cases can he photographed after 

 capture, to transform the dark depths into a magic garden. 



If we inquire into the conditions of existence of this ani- 

 mal world so rich in forms, a peculiar problem arises : we know 

 that organic life is only maintained by the constant introduc- 

 tion of inorganic elements into the cycle of life and that the 

 force which in great measure is able to maintain life is the car- 

 bon dioxide consumption by the plants. Only when sunlight 

 falls on brightly colored plant parts are carbonic acid and 

 water separated into their elements and from these the com- 

 plex protoplasmic molecule built up. Where sunlight and 

 green plants are wanting, there can no new life arise and no 

 organic life be maintained. So the animal life in the deep sea 

 of to-day could not be maintained if a stream of cold south 

 polar water did not pour oxygen and food down into the 

 abyssal depths. 



The deep sea resembles, speaking in terms of national ecol- 

 ogy, a purely industrial state without agriculture dependent 

 for its existence upon lands pursuing agriculture and stock- 

 raising. Hence it follows as a necessary consequence that 

 the fauna of the deep sea cannot have originated there, but 

 must have wandered down into the dark depths from the sun- 

 lit strata rich in plants. ■ 



As soon as we have made clear this indisputable fact, a very 

 significant geological problem confronts us. We ask, When 

 did the deep sea become peopled ? and when did the deep sea 

 basin originate ? 



To be able to solve these questions, we must describe in few 

 words the character of the sediments of the present deep sea, 

 for only by knowing these well is it possible to examine an 

 old rock as to the history of its origin. 



All deposits of the coast region and the shallow continental 

 shelf had their origin on the mainland of the continental areas. 

 The bowlders on the rocky shore, the sand of the dune regions, 

 and the blue or green ooze of the shallow sea are either 

 washed from the strand by the sea waves or borne into the 

 ocean by rivers. The mighty delta masses of the Nile, Ganges 

 or Mississippi bear witness to the vast quantities of continental 

 muds that are carried into the sea. 



