THE ROMANCE OF NATURAL HISTORY. 



tached to the land at a shallow depth, and that, 

 to whatever depth below they now extend, it is 

 only in a dead condition, and has been effected by 

 the subsidence of the supporting land carrying- the 

 coral with it ; while the successive generations of 

 the living polypes, ever working upwards on the 

 old dead foundation, have maintained a living 

 coral structure near the surface, and that nearly 

 in the same outline and form as the original 

 foundation. 



It does not accord with my purpose to enter 

 into the details of this beautiful theory, but rather 

 to present my readers with some vivid pictures of 

 the wonderful structures themselves, as sketched 

 by those who have seen them. In coasting along 

 a tropical reef, the extreme clearness of the water 

 permits the coral shrubs and groves to be dis- 

 tinctly seen, which rise from the blue transparent 

 depths. They take various forms — some massive, 

 with meandering channels over the rounded sur- 

 face; some forming honey -combed blocks formed 

 by the union of thin plates at various angles; 

 many growing like trees or shrubs with leafless 

 branches, more or less ramified, and with the 

 twigs more or less slender and pointed, or thick 

 and rounded. Under water, the whole surface is 

 covered with a layer of jelly-like flesh, of many 

 brilliant colours, formed by the crowding together 

 of the myriad tiny polypes, which protrude their 

 slender tentacles and expanding disks from the 

 individual cells. Even when severed, the branches 

 are exquisitely beautiful so long as they retain the 

 faint purple halo that plays around their ivory 

 tips, but which soon vanishes. A rude touch be- 

 neath the water will cause the lovely tints — 

 brilliant crimson, orange, and emerald green — to 

 disappear, by the withdrawal of the alarmed 

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