398 CORAL AND CORAL REEFS 



to the shells of oysters or creatures of that kind ; for it is 

 the hardening of the internal tissue of the creature, of its 

 internal substance, by the deposit in the body of a material 

 which is exceedingly common, not only in fresh but in sea 

 water, and which is specially abundant in those waters 

 which we know as " hard," those waters, for example, 

 which leave a " fur " upon the bottom of a tea-kettle. 

 This " fur " is carbonate of lime, the same sort of 

 substance as limestone and chalk. That material is con- 

 tained in solution in sea water, and it is out of the sea 

 water in which these coral creatures live that they get 

 the lime which is needed for the forming of their hard 

 skeleton. 



But now what manner of creatures are these which form 

 these hard skeletons ? I dare say that in these days of 

 keeping aquaria, of locomotion to the sea-side, most of 

 those whom I am addressing may have seen one of those 

 creatures which used to be known as the " sea anemone," 

 receiving that name on account of its general resemblance, 

 in a rough sort of way, to the flower which is known as the 

 " anemone " ; but being a thing which lives in the sea, 

 it was qualified as the " sea anemone." Well, then, you 

 must suppose a body shaped like a short cylinder, the top 

 cut off, and in the top a hole rather oval than round. All 

 round this aperture, which is the mouth, imagine that there 

 are placed a number of feelers forming a circle. The cavity 

 of the mouth leads into a sort of stomach, which is very un- 

 like those of the higher animals, in the circumstance that it 

 opens at the lower end into a cavity of the body, and all 

 the digested matter, converted into nourishment, is thus 

 distributed through the rest of the body. That is the 

 general structure of one of these sea anemones. If you 

 touch it it contracts immediately into a heap. It looks at 

 first quite like a flower in the sea, but if you touch it you 

 find that it exhibits all the peculiarities of a living animal ; 

 and if anything which can serve as its prey comes near its 

 tentacles, it closes them round it and sucks the material 

 into its stomach and there digests it and turns it to the 

 account of its own body. , 



These creatures are very voracious, and not at all parti- 

 cular what they seize ; and sometimes it may be that they 

 lay hold of a shellfish which is far too big to be packed 

 into that interior cavity, and, of course, in any ordinary 

 animal a proceeding of this kind would give rise to a very 





