194 BIVALVES. 



slowly over it, and being twisted round the shell, 

 it is easily drawn out. When a sufficient number 

 have been caught, the silk is cut off, and after 

 being twice soaked in tepid water, and once in 

 soap and water, it is spread out to dry in some 

 cool and shady place. Whilst it is yet moist, it 

 is softly rubbed and separated with the hand, 

 and then spread out again. When thoroughly 

 freed from moisture, it is drawn through a comb 

 with the teeth wide apart, and afterwards through 

 a similar instrument, with finer and closer teeth. 

 The more common silk is thus prepared, but that 

 which is destined for finer works, is afterward s drawn 

 through still closer iron combs or cards. When 

 spun, two or three of the threads are mixed with 

 one of real silk, and then it is knitted into gloves, 

 stockings, and even whole garments. When the 

 piece is knitted, it is washed in clean water mixed 

 with lemon juice, gently beaten between the 

 hands, and smoothed with a warm iron. The 

 shells of the Pinna are often ornamented with 

 elevated longitudinal ribs, crossed by striae, some- 

 times terminated by imbricated arched scales, or 

 prominent tubular spines. Some of the young 

 shells of this genus are less than an inch in 

 length, whilst the adults often exceed three feet. 

 The Pinna as well as the Muscle, was much 

 celebrated by the ancients ; they supposed it to 

 harbour within its shell a small crustaceous 

 animal, a kind of shrimp, which was said to be 

 of the greatest use to its companion, by warning 



