CHAPTER X 



MADREPORES, CORALS, AND 

 SPONGES 



PLATE XLIII 

 MADREPORES (i) 



JN some ways these curious creatures are very 

 much like sea anemones, and if you were to 

 find one with its tentacles spread you would be 

 almost sure to think that it was a small anemone. 

 But if you touched it you would find that you 

 had made a mistake, for instead of closing itself 

 up into an almost shapeless lump of jelly, as 

 the anemones do, it would just draw back its 

 tentacles, and leave a kind of flinty skeleton 

 still standing up. For madrepores are really 

 much more like the wonderful little creatures 

 which make coral. They suck lime, in some 

 strange manner which nobody quite understands, 

 out of the sea-water, and build it up round and 

 underneath their own bodies. And if you startle 

 them in any way they draw themselves down 

 inside this shelly covering, and disappear from 

 sight altogether; so that all that you can see 



is a number of thin plates standing upright on 



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