174 
LECTURE XI. 
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, 3'et some have been found of a 
deep red, and others of a pink colour. It is far- 
ther observable, that a pearl, wdien 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- 
