LECTURE XL 



It is furnished with a lengthened tubular tongue 

 or soft trunk, by the assistance of which it depo- 

 sits a small drop of a glutinous fluid on whatever 

 place or substance it wishes to attach itself to, and 

 then, suddenly withdrawing the trunk, forms, in 

 consequence, a thread or ligament ; and repeating 

 this operation a great many times, fastens it- 

 self by a short silken tuft. In the soft or pulpy 

 part of the body of the animal are found the 

 pearls ; the real nature and production of which, 

 as to the oeconomy of the animal, is perhaps still 

 in a great degree unknown. The idea of Reau- 

 mur is not improbable : viz. that the pearls are 

 formed like the concretions called bezoars in qua- 

 drupeds and some other animals. It is said that 

 between one and two hundred pearls have been 

 sometimes found within a single pearl-muscle. 

 Though the general colour of the shell and the 

 pearl is silvery, yet some have been found of a 

 deep red, and others of a pink colour. It is far- 

 ther observable, that a pearl, when cut through, 

 frequently exhibits some extraneous body, as a 

 grain of gravel or other substance in the centre* 

 round which the several lamellae or concentric con- 



