The Treatise on the Organization and Classification of Triloljites, 1)y Professor 

 BuRMEiSTER, HOW presented to the members of the Ray Society, is not merely a translation 

 of the orij^final German edition published at Berlin in 1843, but a new edition, revised, 

 augmented, and in part rewritten by the distinguished Author himself, who has most 

 kindly endeavoured to render the Ray version as complete as possible by embodying all 

 the information which had accumulated since the publication of the German edition. 

 Through the aid of Professor Burmeistcr the Society has been enabled to procure impressions 

 from the original and very beautifid plates. These have also been revised by the Author, 

 and several important figures added. 



The translation has been executed, under the superintendence of the Editors, by 

 Dr. Hermann MLx. In the revision of the first section of the work, they have been kindly 

 assisted by Professor Ansted. 



The translation, especially of the systematic part, is nearly a literal one ; such being, 

 in the opinion of the Editors, most likely to convey the sense of the Author, although 

 elegance of expression may occasionally have thereby been sacrificed. They have carefully 

 abstained from altering any expression of the Author's meaning, and even where they 

 might dissent from his Aaews, have preferred silence to the intrusion of their own opinions. 

 The notes they have added are all of an explanatory or supplementary nature, and especially 

 such as may prove useful to the English reader. 



The Editors feel that they need not dwell on the great importance of the volume 

 which has been committed to their charge. As a dissertation on a most- diflicult tribe 

 of fossil Articidata by an eminent Zoologist, deeply versed in the organization of the great 

 class to which it belongs, the work assumes an importance which can rarely be accorded 

 to palffiontological essays treating of the remains of Invertebrate Animals. 



THOMAS BELL, 

 EDWARD FORBES. 

 London: December 18-16. 



