142 THE AQUARIAN NATURALIST. 



tentacles,, they adhere pretty strongly to it, just as 

 the Actiniae do ; but when they are rudely touched, 

 they contract very quickly ; and, if the irritation be 

 continued, the whole soft parts sink within the cal- 

 careous cup. 



Expanding its delicately tinted arms in the quiet 

 recesses of an aquarium, the Caryophyllia is a truly 

 beautiful object, and, as it seems to be lazily enjoying 

 the sunshine, few would suspect the importance of its 

 labours few would dream that these apparently in- 

 significant animals, by the accumulations of their 

 calcareous skeletons, form the reefs and coral islands 

 of tropical seas the dread of the navigator the ad- 

 miration of the lover of the picturesque the subjects 

 of the closest and most interesting speculations to the 

 naturalist and geologist. 



That masses of rock, many leagues in extent, should 

 be founded in the depths of the ocean, and built up 

 to the height of hundreds of feet, by minute, frail, 

 gelatinous creatures such as these, is indeed a 

 phenomenon calculated to astonish the unversed 

 in zoological science, a fact which has demanded 

 the repeated observation of the most accomplished 

 naturalists and enlightened voyagers to render it 

 intelligible, and the language of poetry to describe 

 the result of their united labours. 



" Millions of millions thus, from age to age, 

 With simplest skill and toil unweariable, 

 No moment and no movement unimproved, 

 Laid line on line on terrace terrace spread, 

 To swell the heightening, brightening gradual mound, 

 By marvellous structure climbing toward the day. 



