150 UNIONISE. 



writers who have treated of pearls, have all taken it for 

 granted that those mentioned by the ancient authors quoted 

 were derived from the Unio. This, however, is by no 

 means clear, and Caesar's buckler was more probably 

 covered with pearls from Mytllus edidis, very much in- 

 ferior in quality and size to those from the fresh-water 

 Pearl Mussel, and agreeing better with the disparaging 

 account of them in Pliny. Those mentioned by Camden* 

 as occurring at the mouth of the Irt, in Cumberland, seem 

 to have been of the same nature. The pearl-fishery at the 

 mouth of the Conway, to which we shall have hereafter to 

 refer, also concerns the Mytllus and not the Unio. Higher 

 up the latter river, however, and in many rivers of all parts 

 of the kingdom, especially in the neighbourhood of moun- 

 tainous districts, the Unio has been at various times fished 

 to a great extent for pearls, and, in all probability, the fame 

 of British pearls that attracted the Roman conqueror was 

 due to the products of the shell before us. The best account 

 of any of these fisheries of the freshwater Pearl Mussel is 

 contained in a curious paper in the seventeenth volume of the 

 " Philosophical Transactions ,, (1693), written by Sir Ro- 

 bert Redding, and communicated by Dr. Martin Lister. 

 This paper has been often referred to by subsequent writers, 

 who, however, seem to have made use of Pennant's short 

 notice of it only, which itself was taken from the abridg- 

 ment, and not from the original. It is a remarkable paper 

 on account of the correctness of observation displayed in the 

 personal statements of the author, who seems to have been 

 a person with considerable natural history powers. His de- 

 scription of both shell and animal is curiously correct as far 

 as it goes. He states that they were fished in the rivers of 

 Tyrone, Derry, Donegal, near Dundalk, near Waterford, 

 * Britannia ; Gough's edition. Vol. iii. p. 189. 



