3IO The Commercial Products of the Sea. 



portion to the depth of the water ; for, notwithstanding the 

 extreme delicacy of the individual threads, they form such 

 a compact tuft that considerable strength is necessary in 

 separating the shells from the rocks to which they are 

 attached. The tuft of silk is broken off and sold to the 

 country women, who wash it in soap and water. They 

 then dry it in the shade, straighten it with a large 

 comb, cut off the useless root part by which it adhered to 

 the animal, and card the remainder. By these means a 

 pound of coarse filaments is reduced to about three ounces 

 of fine useful thread. This is fabricated into various 

 articles for the person, such as shawls, stockings, caps, 

 waistcoats, gloves, purses, etc. The web is of a beautiful 

 yellow brown, resembling the burnished gold hue which 

 adorns the backs of some splendid flies and beetles. 



A very large mollusc, the giant clam (Tridacna gigas), 

 found in the seas of the Eastern Archipelago, has a byssus 

 formed of many tough threads, but slightly elastic, spun 

 by the animal, or rather cast in a mould, thread by thread ; 

 a gelatinous fluid being secreted in a long groove or canal, 

 formed by the foot, which in the air rapidly acquires 

 solidity. When complete, the united threads form a strong 

 cable, adhering by the other extremity to the rock so 

 firmly as to resist the agitation of the sea, and so tough as 

 to be severed only by an axe. Marsden mentions one 

 of these shells which was more than 3 ft. 3 in. long, and 

 2 ft. I in. wide ; and specimens have been seen which had 

 attained the enormous length of four feet. 



