106 A TOUR ROUND NORTH WALES. 



fervants more ftridlly, and prevent their 

 pradtifing fuch fhameful impofitions upon 

 the public. 



The River Conwy was formerly noted 

 for being a pearl fishery ; and pearls have 

 been taken here, at different times, ever 

 fince the Roman conqueft. Suetonius fays, 

 that to get thefe was one of the chief mo- 

 tives all edged for his invafion of this ifland. 

 The Britim and Irifh pearls are found in a 

 fhell-fifb, called by Linnaeus * Mya Marga- 

 ritefera y the Pearl Mufcle, peculiar to flony 

 and rapid rivers. The pearls are faid to 

 be produced from a difeafe in the fim fome- 

 what analogous to the ftone in the human 



* GEN. CHAR. Shell bivalve, gaping at one end. 

 Hinge with a broad thick tooth not let into the op- 

 pofite valve. 



SPEC. CHAR. Shape oval, bending in on one 

 fide. Shell thick, opake, and heavy. Tooth of the 

 hinge fmooth and conical. The length five or fix 

 inches, and breadth about 2$. 



body. 



