Mussel and Coclcle. 97 



Mussels, so called from the ITaiades, fabulous 

 divinities of the streams and rivers. The shells of 

 many of these, which are of considerable thickness, 

 are lined with the most brilliant nacre, and in these, 

 as might be expected, pearls are sometimes found. 

 One species, abundant in some English rivers, called 

 the Ml/ a Margaritifera, or, as some say, TJno eJon- 

 gates J has long been celebrated for this valuable 

 production. It was most likely with pearls from 

 this mollusk that Julius Caesar adorned a breast- 

 plate, which he dedicated to Yenus, and hung up 

 in her temple. The rivers Esk and Conway were 

 formerly celebrated as British pearl fishing-grounds; 

 a Conway pearl was presented by her chamberlain, 

 Sir Eichard Wynn, of Gwyder, to Catherine, Queen 

 of Charles the Second ; and in the royal crown of 

 Britain this jewel is said still to occupy a place. Sir 

 John Hawkins, the circumnavigator of the globe, 

 held a patent for the pearl-fishery of the River Irt, 

 in Cumberland. The rivers of Tyrone and Donegal, 

 in Ireland, have, or had, their pearl-bearing Mus- 

 sels; we read of one which weighed thirty-six 

 carats (a carat is nearly four grains), but not being 

 of perfect shape and colour, it was only valued at 

 forty pounds. We also read of another purchased 

 by Lady Glenlealy, for ten pounds, and found to 



