48 MYA. 



and the shell is only to be classed by other points 

 of generic resemblance. It would perhaps be bet- 

 ter if this genus were recast ; for, as it at present 

 stands, it includes, most palpably, several stolen 

 species. The inhabitants of the Mya burrow in 

 the sand or mud, leaving a channel, through which 

 they occasionally thrust their retractile proboscis. 



Mya ma?'garitifera, a species which is found 

 chiefly in the large rivers of northern latitudes, is 

 known to produce pearls, partial secretions of the 

 same matter which forms the inner coatinp; of the 

 shell, in considerable abundance. The British 

 islands, especially Ireland, have been considered 

 famous for their fisheries of the Mya, and a few 

 pearls of great value have at different periods been 

 obtained from these sources ; but the quality of 

 British specimens in general is by no means held 

 in the highest estimation. 



The Greek original //-uag, from /^jw, to compress, 

 (whence the word Mya is derived,) was formerly 

 applied to the Genus Mytilus. 



