INTRODUCTION. XI 



of the Voluta papalis with the Voluta turbinella, 

 and of the Buccinum maculatum with the Buccinum 

 patulum. How far these objections may be tenable it 

 is not our purpose to enquire, being* ourselves per- 

 suaded that the Linnsean system, though capable of 

 considerable improvement, presents the most simple 

 and concise method of aiding the investig-ation of this 

 branch of natural history. 



The striking dissimilarity of the species in some of 

 the genera is certainly an obstacle to the attainment of 

 the science; we have, therefore, with a view to facili- 

 tate its acquirement, and at the same time not materi- 

 ally to depart from the system we have adopted, formed 

 divisions of the genera, when any marked dissimilarity 

 was observable in the species. And if any of the di- 

 visions retained one leading character throughout, to- 

 gether with some other characters only partially, we 

 have again divided it into families, distinguished by 

 those variations. It is possible that the characters of 

 many of the divisions will be deemed sufficiently dis- 

 tinct to allow of their being" formed into additional ge- 

 nera, without departing from the original system. 



We have been indebted to other writers on Concho- 

 logy for the addition of many new species, and parti- 

 cularly to Mr. Dillwyn's valuable Catalogue of Recent 

 Shells. 



Those species which were not found described or 

 figured in the works of any author to which we had 

 access, are distinguished by an asterisk ; we have also 

 named them, considering them to be new species; 

 and have endeavoured in the catalogue, to place each 



