•2 



In order to escape the censure that attends such undertakings, from 

 many having never been properly finished, the ' Conchologia Syste- 

 matica ' is now publishing in the exact order in which it is ultimately 

 to stand. A Tabula Methodic a, showing the distribution of the genera 

 at one view, is given at the commencement ; every genus, which is then 

 faithfully described in detail, is accompanied with one or more plates of 

 as many species of shells as are considered of interest ; whilst its origin 

 and distinguishing characters, the various situations to which it has 

 been assigned in the system by different authors, and the peculiarities 

 of habit and organization of the animals referred to it, are at the same 

 time fairly discussed. Amongst the genera adopted, are included nearly 

 the whole of those advocated by Lamarck ; the author has at the same 

 time carefully abstained from introducing any new ones of his own, and 

 only such of those proposed by modern authors are admitted as have re- 

 sulted from positive discovery ; genera which it may be fairly estimated 

 would have been as readily acknowledged by Lamarck, had his life 

 been miraculously prolonged. It has, however, been considered useful to 

 notice the majority of these genera in the places to which they refer, and 

 to include them in an index of nomenclature at the end of each volume. 



The Work, which is now publishing in tw T elve parts, is divided into 

 two volumes ; the first, containing the Lepades and Bivalve Mollusks, is 

 illustrated with 130 plates of shells, and the second, containing the 

 Univalve Mollusks, is illustrated with 170 plates, including in all above 

 fifteen hundred figures of more than a thousand species. Nine parts 

 out of the twelve are already published, and the remaining three, which 

 are in active preparation, will appear at intervals of a month, completing 

 the entire work in October. The size, which is demy quarto, has been 

 generally approved of for its convenience ; the engraving has been en- 

 trusted to Mr. G. B. Sowerby, Jun., our first conchological draughts- 

 man ; and the text cannot fail to be admired as a most elaborate spe- 

 cimen of modern printing. 



When the liberal and expensive style in which this work has been 

 got up is considered, it is obvious that the low price at which it is 

 published could not have been attained without having recourse to 

 some already published plates. In many instances, where little novelty 

 occurs, an arrangement has been effected with the Messrs. Sowerby for 

 the use of some of the best plates of ' The Genera of Recent and Fos- 

 sil Shells ' and the ' Conchological Illustrations,' but nearly one hun- 

 dred new plates have been engraved for the purpose of illustrating those 

 genera which have been more materially enriched by modern discovery ; 

 they include several hundred species comparatively new to science, and 

 are of the greatest interest to collectors. Nearly the whole of these 

 occur in the second volume, and may be alone considered adequate to 

 the price of the whole work. 



