54 IIFSSEL AND COCKLE. 



have very beautiful shells. We give a representation of one 

 of each, on Plate YIII. Fig. 2 is the Magellanic Mytilus, {M. 

 Magellanicus,) found chiefly in the Straits of Magellen; it is 

 generally four or five inches long, the shells when polished 

 are , very brilliant, the deep purple colour changing into rich 

 violet, as they are held in different lights. In most cabinets 

 the large fan-like delicate shells of the genus Pinna may be 

 observed; the largest species is that called Pinna fiahellum, 

 taken in the Mediterranean; it sometimes exceeds two feet 

 in length. The first of these names is a Latin word signifying, 

 besides a shell-fish, the fin of a fish, or the wing feathers of 

 a bird — hence the term pinion; it refers to the fin-like or wing- 

 like shape of this shell. Fiahellum means a fan, referring 

 probably to the bissus of the moUusk, which is fine and glossy, 

 like silk, and very abundant. 



Many pretty specimens for figuring might be selected from 

 the Naidm, a family of Fresh -water Mussels, so called from 

 the Naiades, fabulous divinities of the streams and rivers. 

 The shells of many of these, which are of considerable thick- 

 ness, 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 Mya Mar gar it if era, 

 or, as some say, JJno elongates, 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. Tlie 

 rivers Esk and Conway were formerly celebrated as British 

 pearl-fishing grounds; a Conway pearl was presented by her 

 chamberlain. Sir Kichard Wynn, of Gwyder, to Catharine, 

 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 Mussels; 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 £10, 

 and found to be so perfect and admirable, that £80 was 

 afterwards offered for it, and refused. 



