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X. On two new British Species of Mytilus, in a Letter to tin 

 Rev. E. J. Burrow, F.R.S. and L.S. Bij the Pa,. Revett 

 Sheppard, F.L.S. 



Read January 18, 1820. 

 Dear Sir, 

 The publication of the Transactions of the Linnean Society 

 has been attended with great benefit to the concerns of natural 

 history. Many important discoveries are there registered which 

 would not otherwise have become generally known ; and every 

 new discovery adds a fresh link to a chain of wonders, which 

 ought to inspire us with admiration of Him, who by a word called 

 them into existence. Nothing of this kind should be lost ; where- 

 fore I am now desirous of transmitting, by your hands, to the 

 Society an account of two new species of British Fresh-water 

 Mytili. 



So great has been the influx of new species within a few years, 

 that the existence of a necessity for making alterations in the 

 characters of such subjects as have been described by Linnaeus, 

 must be readily allowed by all. Doubtless that great man would 

 have done so himself, had he been in the vigour of life at this 

 time ; or he would have had the mortification of seeing his works 

 rendered of little utility, owing to the inconvenience of the cha- 

 racters given to one species often answering to several others. 

 Thus, Mytilus cygneus, M. incrassatus, M. anatinus, and M. Ma- 

 cula, I consider as distinct species : yet Linnseus's specific cha- 

 racter of M. anatinus will answer to them all. He adds indeed 

 to his character of M. cygneus, " cardine lateralis which he does 



M 2 not 



