5. 



34 



as if the animal was conflantly throwing off part of its 

 Ihell, both externally and internally. Teeth llrong; in 

 one valve a fingle tooth, locking into a bifurcated tooth 

 in the oppofite valve. Length two inches and a half, 

 breadth hve inches. 



Inhabits only the rapid rivers, particularly thofe of the 

 mofl mountainous parts, and rocky torrents: not uncom- 

 mon in the northern parts, and in Wales: is alfo common 

 in the rivers of DevonJJnre, which take their fource from 

 the mountains of Dartmoor, particularly the Aim or 

 Avon. 



This fpecies has long been famous for producing 

 pearls, of a good colour, and of confiderable lize: and 

 was formerly fought after for that purpofe. Conzoay was 

 noted for them : and we are informed by Camden that 

 Sir John Hawkins had a patent for fifhing them in the 

 river Irt, in Cumberland. 



Ov/VLis. Mya Ovalis. Pi/It. Cat. Dorfd. p. 27. 



Mya Piaorum. Br. ZooL t. 43. f. 17. 



Lijicr. Conch, t. 146. f. 1.— t. 147. f. 2. 3. 

 Id. Arr^J. t. 2. 30. 



Da Cojh. \^.22?> t. 15 f.4.— Do;/. Br Shells. 

 iii. t. ?,9.—Shrcet. Fliifscon. i. 3. f. 2. 3. 



M. with a Rrong oval fhcll, of a dulky-grecn colour, 

 almofl black at the fmaller end, marked with fe\'eral con- 

 centric 



