ECHINODERMATA 25 



echinoderms. Several dozen species are used as food, especially 

 by the Chinese, and other orientals, under the name trepang; they are 

 also called b$che-de-mer. Some species bring very high prices, others 

 seem less desirable. 



The animals, some of which may reach a length of two feet, are 

 eviscerated, the leathery walls are then boiled, soaked in fresh water, 

 smoked, and dried. The result is an irregular mass of rubber-like 

 substance which can be transported easily and is made into soup and 

 other articles of diet, which are said to be very palatable. 



FIG. 1 8. A crinoid, Pentacrinus madearanus. Xi. Only a part of the 

 stem shown. (From Hegner, College Zoology, after Cambridge Natural History, 

 from Thompson.) 



Trepang is prepared by the Chinese of California and Hawaii, 

 but the chief centres are in the Orient; for example 600 tons annu- 

 ally are collected from the north coast of Australia, and the annual 

 trade amounts to hundreds of thousands of dollars. Considerable 

 quantities are also collected in the West Indies. 



The Ophiuroidea have practically no economic importance and 

 the same is true for the Crinoidea except for their aid in forming lime- 

 stone beds and in enabling geologists to determine geological horizons. 



