INTRODUCTION. XUl 



sively to the shells. The naked MoUusks of all tribes 

 were but seldom sought for. Montagu and Leach, it is 

 true, called attention in England to the beauty and pecu- 

 liarities of these animals ; Jameson and Fleming did the 

 same service for these and still less attractive tribes in 

 Scotland, but until within the last twenty years neither the 

 Mollusks without shells, nor the soft parts of the testaceous 

 families could be said to be estimated at their due impor- 

 tance, or to be regarded with systematic attention. How 

 much has been done since, and how much is being done 

 now, we have endeavoured to record, as far as our limits 

 would admit, in the following history. 



In like manner, but little was known of the habits, range, 

 and distribution, geographical and bathymetrical, of the 

 Mollusks indigenous to our seas. They were looked upon 

 too frequently as objects of mere elegant curiosity, to be 

 made the subjects of laborious research and observations 

 conducted amid their native haunts. The importance of 

 a knowledge of the facts of their mode of life, and the 

 physical conditions affecting their diffusion, was not under- 

 stood, nor indeed, until geology called loudly for information 

 so necessary to the progress of that world-dissecting science, 

 was the inquiry deemed of sufficient interest to attract the 

 attention of more than some half a dozen observers. British 

 naturalists can now boast of having investigated the phe- 

 nomena of the molluscous fauna of their native islands 

 more thoroughly than has been done by their colleagues in 

 any foreign country. The number of facts now recorded 

 respecting the distribution of the species inhabiting our 

 seas is very considerable, and sufficient to warrant ex- 

 tensive generalizations. We offer the following brief 

 review of the principal results of our present acquaint- 

 ance with this peculiarly interesting branch of inquiry. 



