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