50 The Under-Water World 



instantaneous flashes. " A marvellous 

 effect was produced by vast numbers 

 over the whole surface of the sea ; it was 

 as if we were steaming through shower 

 after shower of submarine rockets which 

 burst just below the surface/' 



The popular sea anemones and corals 

 are similar to the jelly-fish in structure, 

 the latter being small anemones with the 

 power of obtaining carbonate of lime 

 from the sea water and sometimes form- 

 ing solid masses. The anemones and 

 soft or flexible corals are represented by 

 numerous forms in British waters and 

 differ from the hydroid polyps, which 

 they often resemble superficially, in the 

 possession of a tube or gullet between 

 the mouth and the body cavity. 



The anemones, although mainly sed- 

 entary in habit, are capable of gliding 

 slowly over any hard surface. A few 

 are burrowers, anchoring themselves to 

 buried rocks, and withdrawing into the 



