CCELENTERATA . 1 9 



the Gauls ornamented their weapons with the material until the 

 oriental demand became so great as to use up the entire supply. 



A cheap variety of precious coral is collected in Japan; it is also 

 found off the coasts of Ireland and Australia. There is a black coral 

 dredged in the Persian Gulf. The African fisheries have changed hands 

 several times but are now under French control, so that non-French 

 dredgers have to pay a heavy royalty. Previous to the French 

 Revolution, Marseilles was the chief centre for collecting and work- 

 ing the coral; now Naples, Genoa and Rome are the chief centres. 



FIG. 12. A small atol. A sketch of Whitsunday Island in the South Pacific- 

 (From Hegner, College Zoology, after Sedgwick and Darwin.) 



The Algerian reefs are divided into 10 regions, only one of which is 

 dredged each year, 10 years being considered time enough to allow the 

 beds to recuperate. They are dredged in waters from 25 to 1000 feet, 

 though mostly in the shallower depths. 



The value varies according to color, size and current demand, 

 the last fluctuating greatly with the changes of fashion. The finest 

 tints may bring $400 to $600 per ounce. Ordinary reds in small 

 pieces, $10 per ounce. Fine pieces called " collette, " used for children's 

 necklaces, etc., bring $i per ounce. Very large pieces are much in 

 demand in China for the official buttons of the mandarins. 



