Sect. I. THE GEOWTH OF COKAL-KEEFS. 87 



species of coral in the circumtropical seas must be 

 very great; in the Eed Sea alone, 120 kinds, accord- 

 ing to Ehrenberg, 1 have been observed. 



The same author has observed that the recoil of 

 the sea from a steep shore is injurious to the growth 

 of coral, although waves breaking over a bank are 

 not so. Ehrenberg also states, that where there is 

 much sediment, placed so as to be liable to be moved 

 by the waves, there is little or no coral ; and a col- 

 lection of living specimens placed by him on a sandy 

 shore died in the course of a few days. 2 An experi- 

 ment, however, will presently be related, in which 

 some large masses of living coral increased rapidly in 

 size, after having been secured by stakes on a sand- 

 bank. That loose sediment should be injurious to 

 the living polypifers, appears at first sight probable ; 

 and in sounding off Keeling atoll and Mauritius, the 

 arming of the lead invariably came up clean, where 

 the coral was growing vigorously. A strange belief, 

 which, according to Captain Owen, 3 is general amongst 

 the inhabitants of the Maldiva atolls, namely, that 

 corals have roots, and therefore grow up again if 

 merely broken down to the surface, but if rooted 

 out, are permanently destroyed, — I am inclined to 

 believe arises from the fact that loose sand injures 

 the polypifers. For it is probable that sand would 



1 Ehrenberg iiber die Natur, &c. &c. p. 46. 



2 Ibid. p. 49. 



3 Captain Owen on the Geography of the Maldiva Islands, Geograph. 

 Journal, vol. ii. p. 88. 



