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CHAPTER XXII. 



LIFE ON THE OCEAN" SUEFACE 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. Pela- 

 gonemertes described. Phosphorescence of Pelagic Animals. Giant 

 Pyrosoma. Uncertainty as to Range in Depth of Pelagic Animals. 

 The Depth of the Oceans and Depression on the Earth's Surface. 

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

 periment showing this made by Mr. Buchanan. Conditions under 

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

 Food of Deep-Sea Animals. Experiment on Rate of Sinking of a 

 Salpa. Vegetable and Animal Debris Dredged from Great Depths. 

 The Deep Sea, a High Road for Distribution of Animals. Deep- 

 Sea Faunas and Alpine Floras Compared. Nature of 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, Mosquitos, 

 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. Smallness 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 peculiar 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, 



