2

PREFACE.

hand, I have had but few opportunities of examining original specimens from Englandand America . My present work therefore certainly ought not to he considered as complete ;it will unquestionably admit of much improvement, and for this purpose I should gratefullyreceive any assistance, especially of original specimens of species hitherto unknown to me,even if it were only for temporary inspection. Indeed I should be satisfied with goodfigures of such specimens, provided they were accompanied by explanatory descriptions.Such illustrations being rare, I have made it my principal object to render the plates containedin this work as perfect as possible. I have had the good fortune to meet with an artistin the person of Mr. A. Andorff, of Berlin, whose talents and whose execution of theengravings are such, that I can, without the slightest hesitation, recommend the plates, whichwere executed by him, as patterns for imitation to all artists. Every person acquaintedwith the subject will undoubtedly agree with me, that better and more beautiful representa-tions of Trilobites, or figures more true to nature in every respect, are not in existence.

Halle ; May 8 th, 1843.