H4 The Outline of Science 



life. Wherever the long arm of the dredge has reached, animals 

 have been found, e.g. Protozoa, sponges, corals, worms, starfishes, 

 sea-urchins, sea-lilies, crustaceans, lamp-shells, molluscs, ascid- 

 ians, and fishes a very representative fauna. In the absence of 

 light there can be no chlorophyll-possessing plants, and as the 

 animals cannot all be eating one another there must be an extrane- 

 ous source of food-supply. This is found in the sinking down of 

 minute organisms which are killed on the surface by changes of 

 temperature and other causes. What is left of them, before or 

 after being, swallowed, and of sea-dust and mineral particles of 

 various kinds forms the diversified "ooze" of the sea-floor, a soft 

 muddy precipitate, which is said to have in places the consistence 

 of butter in summer weather. 



There seems to be no bacteria in the abysses, so there can be 

 no rotting. Everything that sinks down, even the huge carcase 

 of a whale, must be nibbled away by hungry animals and digested, 

 or else, in the case of most bones, slowly dissolved away. Of the 

 whale there are left only the ear-bones, of the shark his teeth. 



Adaptations to Deep-sea Life 



In adaptation to the great pressure the bodies of deep-sea 

 animals are usually very permeable, so that the water gets 

 through and through them, as in the case of Venus' Flower 

 Basket, a flinty sponge which a child's finger would shiver. But 

 when the pressure inside is the same as that outside nothing 

 happens. In adaptation to the treacherous ooze, so apt to 

 smother, many of the active deep-sea animals have very long, 

 stilt-like legs, and many of the sedentary types are lifted into 

 safety on the end of long stalks which have their bases embedded 

 in the mud. In adaptation to the darkness, in which there is only 

 luminescence that eyes could use, there is a great development of 

 tactility. The interesting problem of luminescence will be dis- 

 cussed elsewhere. 



As to the origin of the deep-sea fauna, there seems no doubt 



