Class VI. MYA. GAPER. 163 



Lin. Syst. 1112. Gm. Lin. Scheffer Lapland, 145. 10. marga- 



32ig. Faun. Suec. No. Lin. Tr. viii. 40. ritifera. 



1)6GLTl 



2130. Mont. Test. Br. 33. 



List. Angl. App. tab. \.Jig. 1. 



M. with a very thick coarse opake shell ; often 

 much decorticated ; oblong, bending inward on 

 one side, or arcuated ; black on the outside ; 

 usual breadth from five to six inches ; length 

 two and a quarter. Tab. xlvi. Jig. Q. 



Inhabits great rivers, especially those which 

 w r ater the mountanous" parts of Great Britain. 



This shell is noted for producing quantities 

 of pearl. There have been regular fisheries 

 for the sake of this pretious article in several 

 of our rivers. Sixteen have been found within 

 one shell. They are the disease of the fish, 

 analogous to the stone in the human body. 

 On being squeezed, they will eject the pearl, 

 and often cast it spontaneously in the sand of 

 the stream. 



The Conwy was noted for them in the days 

 of Camden. A notion also prevales, that Sir 

 Richard JVynn, of Gwydir, chamberlain to 

 Catherine queen to Charles II. presented her 

 majesty with a pearl (taken in this river) which 

 is to this day honored with a place in the regal 



M 2 



