PLATE LXXIII. 



Mya Margaritifera : testa ovata anterius coarctata, cardinis dente 



primario conico, natibus decorticatis. Linn, 



Fn. Suec. 2130. — Gruel. Linn. Sijst. Nat. 



3219. sp. 4. 

 Mya nigrescens crassa & ponderosa margaritifera. Margaritifera. 



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



fg. 3. 3. 

 Musculus niger omnium crassissima et ponderosissima testa. Conchs 



longas species. Gesn. &" Aldrov. List. App. 



11. An. Angl. p.W. tit. 31. tab. I. fig. I. &' 



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



fab. 1 . fig. 1 . 

 Musculus niger omnium longe crassissimus. Conchse longae species. 



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

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



Martin's West. Isles, p. 7. 6(c. 



Pearl Muscles. Leigh Lancashire, p. 134. 

 Mytulus major margaritiferus. Wallis Northumb. p. 403. No. 42. 

 Mya margaritifera. Pearl. Pejtn. Br. Zool. No. 18. tab. 4:3. fig. 18. 



*' This sliell," 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 fifh 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 

 noti(^n also prevails that Sir Richard Wynne, of Gwydir, chamber- 



