The Fourth \'oltiiuc of the Mannal of Couchology contains 

 nionograplis ol' four important ianiiiies, eiul>racing genei'a of 

 which many rei)resentatiA'es are included in the cabinet of every 

 collector of marine shells. It is hoped that it will he found 

 useful in lacilitating the identification of specimens, as well as 

 in correcting the hitherto ver}' confused synon3'm3^ 



The kind oflices of many correspondents in furnishing speci- 

 mens (particularlj' unfigurcd types), drawings and information 

 concerning the species, are again gratefull}- acknowledged ; and 

 I am equally indebted to others for their endeavors to promote 

 the sale of the Manual. I shall endeavor to deserve and recom- 

 pense this active interest in behalf of the work by making it 

 as thorough as circumstances will permit. 



G. W. T., Ju: 



January^ 1882. 



