HOLOTHURIAD^;. 201 



being alone exposed, and floating in the water above, 

 apparently as a lure for prey. Some may also be observed 

 lying on the rocks, their bodies completely encrusted with 

 coral sand, which may either have been accumulated by a 

 previous burrowing, or thus used as a disguise. It would 

 appear to be partly the instinct of the animal to take its 

 prey in ambush ; but what that prey is, as well as the 

 entire economy of these Molluscs, remains a perplexing 

 mystery. Their intestines invariably contain many hard 

 and solid masses of madreporic rock or tree-coral, some of 

 them more than an inch in length, and all moulded as 

 pellets to the calibre of the intestinal canal. It is difficult 

 to say how these stony bodies have been obtained by the 

 Trepang, though it is easy to conceive that they may be 

 rendered serviceable as nutriment by the assimilation of 

 the animal matter they contain. It is this animal which 

 the Malays of the Oriental Isles seek so diligently for the 

 supply of the China market, where it obtains a good price 

 when well preserved. It is employed by the Chinese in 

 the preparation of nutritious soups, in common with an 

 esculent sea-weed, shark's fins, edible birdVnests, and 

 other materials, affording much jelly." Jaeger says the 

 intestines are extracted, the animal then boiled in sea- 

 water, and dried in smoke. 



The chief writers on the subject of the Holotlmriadre 

 are Delia Chiagi, a distinguished anatomist of Naples ; 

 Jaeger, a German physician ; and Brandt, a Russian 

 naturalist. The two latter gentlemen have instituted 

 many genera, and added greatly to the number of species ; 

 but it seems to me that they have multiplied the genera 

 overmuch, and not always based them on the soundest and 

 most permanent characters. 



The British Holothuriadie belong to four families, viz. 



