CHAPTER XXII. 



LIFE ON THE OCEAN SURFACE AND IN THE DEEP 

 SEA. ZOOLOGY AND BOTANY OF THE SHIP. 

 CONCLUSION. 



Plants of the Ocean Surface. Fauna of the Sargasso Sea. Protective 

 Colouring of Pelagic Animals. Variety of Pelagic Animals. 

 Flight of the Albatross. Flight of Flying-fish. A Pelagic Insect. 

 Pelagonemertes described. Phosphorescence of Pelagic Animals. 

 Giant Pyrosoma. Uncertaint3' as to Range in Depth of Pelagic 

 Animals. The Depth of the Oceans and Depressions on the Earth's 

 Surface. Deep-Sea Dredging. Vast Pressure existing in the Deep 

 Sea. Experiment showing this made by Mr. Buchanan. Conditions 

 under which Life Exists in the Deep Sea. Range of Plants in 

 Depth. Food of Deep-Sea Animals. Experiment on the Rate of 

 Sinking of a Salpa. Vegetable and Animal Debris Dredged from 

 Great Depths. The Deep Sea, a High Road for the Distribution of 

 Animals. Deep-Sea Faunas and Alpine Floras Compared. Nature 

 of the Deep-Sea Fauna a source of Disappointment. Remarkable 

 Deep-Sea Ascidian. Localities' specially Rich in Deep-Sea Forms. 

 Relations of Deep-Sea Animals to One Another. Phosphorescent 

 Light in the Deep Sea. Colours of Deep-Sea Animals. Cockroaches, 

 Moths, Mosquitoes, House-flies, Crickets, Centipedes and Rats on 

 board the "Challenger." Plants on Board the Ship. Pet Parrot, 

 Cassowary, Ostriches, Tortoises, Spiders, Fur-Seal, and Goat on 

 Board. Adaptation to Sea Life. Small ness of the Earth's Surface. 

 Slow Rate of Travelling. Man and possibly Protoplasm existent on 

 the Earth alone. Necessity for Immediate Scientific Investigation of 

 Oceanic Islands. 



Plants and Animals of the Ocean Surface. — The three- 

 fourths of the surface of the earth which is covered with sea is 

 thickly tenanted by its own pecuUar forms of vegetable and 

 animal life. These forms of life are termed " Pelagic," to 

 distinguish them from the Marine animals and plants which 

 inhabit the shores and sea-bottoms ; they inhabit the surface 

 waters of the open ocean and reach the shores only when 

 washed thither accidentally by the waves and currents. Some 

 of these forms, such as the Pteropods, Ctenophora, and Siphotio- 

 phora, belong to groups peculiar to the sea surface, and have, 

 no doubt, a most ancient connection with it, whilst others are 



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