

PEARL MUSCLE. 371 



was thrown up on the coast, at above thirty miles distance from the 

 spot where he descended. With respect to the animal inhabiting the 

 pearl-shell, it is (we know) popularly called the pearl-oyster ; but in 

 reality belongs to the Linnaean genus Mytylus. It is furnished with a 

 lengthened tubular tongue or soft trunk, by the assistance of which 

 it deposits a small drop of a glutinous fluid on whatever place or 

 substance it wishes to attach itself to, and then, suddenly withdraw- 

 ing the trunk, forms, in consequence, a thread or ligament ; and re- 

 peating this operation a great many times, fastens itself 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 ceconomy of the animal, is perhaps still in a great degree un- 

 known. The idea of Reaumur is not improbable : viz. that the 

 pearls are formed like the concretions called bezoars in quadrupeds, 

 and some other animals. It is said that between one and two hun. 

 dred 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 farther observable, that a pearl, when cut through, frequently 

 exhibits some extraneous body, as a grain of gravel or other sub- 

 stance in the centre, round which the several lamellae or concentric 

 concretions have been formed*. Besides those found in the body 

 of the animal, several are often observed rising from the internal 

 surface of the shell, to which they are closely attached, so as not to 

 be completely round, and are therefore considered as of little value. 

 The largest pearl-shells, and such as are most encrusted with ex. 

 traneous marine substances, as Serpulae, Corals, &c. are in general 

 observed to be most productive of pearls; while the smaller and 

 smoother shells afford but few, or so small as to be of no import- 

 ance in commerce. 



In addition to what has been said relative to Pearls, we may add, 

 that irregular or grape.shaped pearls sometimes occur, which seem 

 to be owing to a coalescence of several smaller ones into one mass. 

 One of the noblest pearls on record is that which Cleopatra is ab- 

 surdly said to have dissolved in vinegar, during au entertainment 



* According to ,Cuvier, pearls may be considered as formed by an extrava* 

 sation of the calcareous matter with which the animal is furaiihed, for the aug- 

 mentation of its shell. 



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