STRUCTURE OF CORAL ISLANDS. 16] 
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, béche de mer, are corruptions of 
the Portuguese bicho do mar, which means sea-worm or sea-slug. 
Il. 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 after 
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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