IV PREFACE. 



The plan followed in the present undertaking has been to give 

 one characteristic figure of each species, and the arrangement 

 adopted has been that of LinnaBus. The Author is well aware 

 that in this age of general novelty he shall be censured by the 

 young, and perhaps by the experienced conchologist, for adhering 

 too tenaciously to the principles of his early master ; but let it be 

 remembered, that all systems built on artificial foundations must 

 be liable to objection, and that it still remains to be proved 

 whether the present innovators had not better have trusted to the 

 Linnean method, with such additions and divisions as its great 

 author might be supposed to have made had he now been living, 

 than by an extreme multiplication of the genera, rather to increase 

 than remove the difficulty of determining the species. 



With a desire in some measure to accommodate those who 

 have adopted the French arrangement, the Author has added the 

 divisions of Lamarck, referring his genera to the figures in the 

 Index Testaceologicus. 



It may not be improper to remark that all the plates (with the 

 exception of the first six by that excellent artist the late Mr. 

 Sowerby) have been executed under the immediate inspection of 

 the Author, and every attention paid to make the figures as accu- 

 rate as possible. To accomplish this purpose recourse has always 

 been had to the shells whenever they could be procured, so that the 

 figures are for the most part original. And here the Author has 

 great pleasure in acknowledging his obligation to JVI rs. Mawe, 

 Mr. J. and Mr. G. B. Sowerby, who with their usual liberality 

 have allowed him the free use of their extensive collections towards 

 the completion of his task. 



