PLATE LXX1II. 



Mya Margarittfera : testa ovata anterius coarctata, cardinis dente 



primario conico, natibus decorticatis. Linn. 



Fn. Suec. 2130. — GmeL Linn. Si/st. Nat. 



3219. sp. 4. 

 Mya nigrescens crassa & ponderosa margaritifera. Margaritifera. 



Da Costa Br. Conch, p. 225. sp. 53. tab. 15. 



fig. 3. 3. 

 Musculus niger omnium crassissima et ponderosissima testa. Concha 



longae species. Gesn. SC Aldroii, List. App. 



II. An. Angl. p. 11. tit. 31. tab. 1. fig. 1. K 



App. H. An. Angl. in Goed. p. 15. tit. 31. 



tab. I. fig. 1. 

 Musculus niger omnium longe crassissimus. Concha? longse species. 



Gefn. & Aldr. Hist. Conch, tab. 149. fig. 4. 

 Musculi marcaritiferi. Bede Hist. Ecclesiast. I. I.e. 1. 



o 



Martin's West. Isles, p. 1. Kc. 



Pearl Muscles. Leigh Lancashire, p. 134. 

 Mytulus major margaritiferus. Wallis Nor thumb, p. 403. No. 42* 

 Mya margaritifera, Pearl. Perm. Br. Zool. No. 18. tab. 43, fig. 18. 



" This shell," says Pennant, " is noted for producing quantities 

 of pearl. There have been regular fisheries for the sake of this pre- 

 cious article in several of our rivers. Sixteen have been found in one 

 shell. They are the disease of the fi£h 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 Conway was noted for them in the days of Camden. A 

 notion also prevails that Sir Richard Wynne, of Gwydir, chamber- 



D9 



