CONTENTS. 



PAGE 



Preface ........ ] 



Introduction ....... 3 



CHAPTER I. 



On the Visible Structure of the Body of the Trilobites . . 13 



CHAPTER II. 



Affinity of the Trilobites to the Existing Articulata . . .31 



CHAPTER III. 



Systematic Arrangement of the Species .... 53 



Appendix . . . . . . . .112 



Supplementary Appendix by the Editors .... 121 



Description of the Plates . . . . . .129 



Index of Genera and Species enumerated by the Author . . 133 



