INTRODUCTION. 



The object of this Catalogue has been to give the Family, 

 Generic and Specific characters of the different species of 

 Bivalve Shells, accompanied with their chief Synonyms. 

 The species in the British Museum are marked with the 

 letters B.M. on the outer margin. 



This part has been prepared by M. Deshayes of Paris, 

 who is now occupied on the succeeding Famihes. 



JOHN EDWARD GRAY. 



Jiine 27, 1853. 



