176 MYTILID^. 



states, the fishermen huilt up piles of stones among the 

 rocks to keep their mussels safe. 



We have alluded to the pearls procured from this species 

 when treating of the Unio margariti/erus.* They are com- 

 monly small, ill-coloured, and of little value, yet have been 

 at various times much sought for. The following passage in 

 Camden-f- about the pearls in Cumberland, evidently refers 

 to these. " Higher up the little river that runs into the 

 sea, in which the shell-fish having by a kind of irregular 

 motion taken in the dew, which they are extremely fond 

 of, are impregnated and produce pearls, or to use the poet's 

 phrase, hacca. cochleeB, shell berries, which the inhabitants, 

 when the tide is out, search for, and our jewellers buy of 

 the poor for a trifle, and sell again at a very great price.^^ 

 A very curious account of a recent pearl fishery in North 

 Wales is given by a correspondent in Loudon's Magazine 

 of Natural History, for ] 830. The writer has confounded 

 the Mytilus edulis with the Unio. To the latter his re- 

 mark on pearls " found up the river " only applies. We 

 quote the letter nearly entire : — 



" The pearl mussel is found in abundance in the river 

 Conway, in North Wales, and is collected by many of the 

 natives, who obtain their livelihood entirely by their in- 

 dustry in procuring the pearls. When the tide is out they 

 go in several boats to the bar at the mouth of the river, 

 with their sacks, and gather as many shells as they can 

 before the return of the tide. The mussels are then put 

 into a large kettle over a fire to be opened, and the fish 



* Since our account of that shell was printed, Dr. Knapp has communicated 

 information respecting the pearls found in it in Scotland. He saj-s, " they are 

 now rare, the price of fine "pearls of good lustre and water varying from two 

 shillings to ten or twelve pounds, according to size. Round pearls, perfect in 

 every respect, about the size of a pea, are worth three or four pounds." 



t Camden's Britannia, Gough's edition, vol. iii. p. 189. 



