BIVALVES. 29 
and hung it in her temple at Rome; he further 
adds that they (probably from Mytilus edulis) 
were small and ill-coloured, and Tacitus says the 
same; but the Venerable Bede, on the other 
hand, states that the British pearls were excellent 
and of all colours—reddish, pale violet, and 
green. In an old translation of Boetius, by 
Bellenden (1541), the following allusion is made 
to British pearls :—“ In the horse mussillis are 
generit perlis. Thir mussillis airlie in the 
morning, when the lift is clear and temperate, 
openis thair mouthis a little aboue the watter, 
and maist gredelie swellis the dew of heaven, 
and aftir the measure of the dew they swell, 
they conceive and bredis the perle.”? Camden, 
still later, in his ‘Britannica,’ speaks of the 
shell-fish of the little river Irt, in Cumberland, 
“that they, by a kind of irregular motion, take 
in the dew and produce pearls.” 
The Pearl Mussel was formerly an object of 
considerable fisheries in our own country, as it 
is now in some parts of Germany. So, also, the 
common mussel, a pearl fishery of which con- 
tinued to exist up to a very recent period at the 
mouth of the river Conway, in North Wales. 
A patent was also granted early in the present 
century to fish for pearls at the mouth of the 
river Irt, in Cumberland. Higher up both 
rivers, however, the Unio has been at various 
