STRUCTURE OF CORAL ISLANDS. 161 



two feet or more. They live just under the sand in the shal- 

 low waters, with the head projecting and bearing a beautiful 

 feathery rosette or flower which is branchial in nature. To 

 fit them for exportation, the holothuria, of which half a dozen 

 different kinds are taken, are slit open, boiled, and then dried, 

 in which last state they look like "smoked sausages. Dr. S. 

 "Wells Williams says, in his " Middle Kingdom," that " when 

 soaked in water, the material resembles pork rind, and is like 

 that in taste when stewed." They are brought to China by the 

 Malays from Macassar, and elsewhere. There are also large 

 drying-houses at the Feejees, and ships from America make 

 their occasional visits to collect them, with the aid of the Fee- 

 jees, and to dry and load up for China. The term biche de mar, 

 and also the French form of it, beclie de m,er, are corruptions of 

 the Portuguese bicJio do mar, which means sea-worm or sea-dug. 



II. STRUCTURE OF CORAL ISLANDS. 



I. FORMS AND GENERAL FEATURES. 



Coral islands resemble the reefs just described, except that 

 a lake or lagoon is encircled instead of a mountainous island. 

 A narrow rim of coral reef, generally but a few hundred yards 

 wide, stretches around the enclosed waters. In some parts 

 the reef is so low that the waves are still dashing over it into 

 the lagoon ; in others it is verdant with the rich foliage of the 

 tropics. The coral-made land, when highest, is seldom more 

 than ten or twelve feet above high tide. 



When first seen from the deck of a vessel, only a series of 



dark points is descried just above the horizon. Shortly aftei 



the points enlarge into the plumed tops of cocoa-nut trees, and 



a line of green, interrupted at intervals, is traced along the 



water s surface. Approaching still nearer, the lake and its belt 

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