Handbook of Paleontology 83 



Here are new types of creatures, among them jelly- 

 fishes, crustaceans, squids, fishes etc. of strange aspect. 

 These animals are small or of medium size and most 

 of them have phosphorescent lights. Animals become 

 fewer and fewer in number with increasing depth. 

 The greatest depth from which animals have been 

 dredged is 3% miles, in the North Atlantic (a fish), 

 and the greatest depth known in any ocean is that of 

 6.08 miles in a spot in the neighborhood of the Philip- 

 pines. The creatures of each level in the depths feed 

 upon the life of the level above, all therefore being 

 supported by the creatures of the twilight zone, which 

 in turn feed upon the plants at night. Since condi- 

 tions at these levels are uniform in all oceans, the 

 animal life is found to be practically the same every- 

 where and its variety lessened rapidly below the twi- 

 light zone. 



The reason why marine animals are most abundant 

 nearer land is that they are ultimately dependent upon 

 the plant life, which in turn subsists upon the nutri- 

 tive material which the rivers and streams bring down 

 to the sea or the rains wash from the land. Thus we 

 find that the deep waters of precipitous coasts have 

 more deep-sea creatures than the same depths farther 

 from the shore. It appears that the deep-sea forms are 

 not so fundamentally different from the types of the shal- 

 lower waters, but rather all seem to be migrants from 

 shallow water habitats which have become adapted to 

 life in the depths. There are no examples known of any 

 new race of animals which dwells exclusively in the 

 abyssal realm. Except for a few minor types all the 

 groups represented in the deeps also are found in the 

 shallow waters. The mud-eating echinoderms probably 



