Chapter II: Preface

The Editors feel that they owe an apology and some explanation to the readers of _The Cambridge Natural History_ for the delay which has occurred in the issue of this, the fourth in proper order, but the last to appear of the ten volumes which compose the work. The delay has been due principally to the untimely death of Professor W. F. E. Weldon, who had undertaken to write the Section on the Crustacea. The Chapter on the Branchiopoda is all he actually left ready for publication, but it gives an indication of the thorough way in which he had intended to treat his subject. He had, however, superintended the preparation of a number of beautiful illustrations, which show that he had determined to use, in the main, first-hand knowledge. Many of these figures have been incorporated in the article by Mr. Geoffrey Smith, to whom the Editors wish to express their thanks for taking up, almost at a moment’s notice, the task which had dropped from his teacher’s hand.

A further apology is due to the other contributors to this volume. Their contributions have been in type for many years, and owing to the inevitable delays indicated above they have been called upon to make old articles new, ever an ungrateful labour.

The appearance of this volume completes the work the Editors embarked on some sixteen years ago. It coincides with the cessation of an almost daily intercourse since the time when they “came up” to Cambridge as freshmen in 1880.

S. F. HARMER.
A. E. SHIPLEY.

_March 1909._

CONTENTS

PAGE

SCHEME OF THE CLASSIFICATION ADOPTED IN THIS VOLUME xi

CRUSTACEA

CHAPTER I

CRUSTACEA

GENERAL ORGANISATION 3

CHAPTER II

CRUSTACEA (_continued_)

ENTOMOSTRACA—BRANCHIOPODA—PHYLLOPODA—CLADOCERA—WATER-FLEAS 18

CHAPTER III

CRUSTACEA ENTOMOSTRACA (_continued_)

COPEPODA 55

CHAPTER IV

CRUSTACEA ENTOMOSTRACA (_continued_)

CIRRIPEDIA—PHENOMENA OF GROWTH AND SEX—OSTRACODA 79

CHAPTER V

CRUSTACEA (_continued_)

MALACOSTRACA: LEPTOSTRACA—PHYLLOCARIDA: EUMALACOSTRACA: SYNCARIDA—
ANASPIDACEA: PERACARIDA—MYSIDACEA—CUMACEA—ISOPODA—AMPHIPODA:
HOPLOCARIDA—STOMATOPODA 110

CHAPTER VI

CRUSTACEA MALACOSTRACA (_continued_)

EUMALACOSTRACA (_CONTINUED_): EUCARIDA—EUPHAUSIACEA—COMPOUND EYES—
DECAPODA 144

CHAPTER VII

CRUSTACEA (_continued_)

REMARKS ON THE DISTRIBUTION OF MARINE AND FRESH-WATER CRUSTACEA 197

CHAPTER VIII

CRUSTACEA (_continued_)

TRILOBITA 221

ARACHNIDA

CHAPTER IX

ARACHNIDA—INTRODUCTION 255

CHAPTER X

ARACHNIDA (_continued_)

DELOBRANCHIATA = MEROSTOMATA—XIPHOSURA 259

CHAPTER XI

ARACHNIDA DELOBRANCHIATA (_continued_)

EURYPTERIDA = GIGANTOSTRACA 283

CHAPTER XII

ARACHNIDA (_continued_)

EMBOLOBRANCHIATA—SCORPIONIDEA—PEDIPALPI 297

CHAPTER XIII

ARACHNIDA EMBOLOBRANCHIATA (_continued_)

ARANEAE—EXTERNAL STRUCTURE—INTERNAL STRUCTURE 314

CHAPTER XIV

ARACHNIDA EMBOLOBRANCHIATA (_continued_)

ARANEAE (_CONTINUED_)—HABITS—ECDYSIS—TREATMENT OF YOUNG—MIGRATION—
WEBS—NESTS—EGG-COCOONS—POISON—FERTILITY—ENEMIES—PROTECTIVE
COLORATION—MIMICRY—SENSES—INTELLIGENCE—MATING HABITS—FOSSIL
SPIDERS 338

CHAPTER XV

ARACHNIDA EMBOLOBRANCHIATA (_continued_)

ARANEAE (_CONTINUED_)—CLASSIFICATION 384

CHAPTER XVI

ARACHNIDA EMBOLOBRANCHIATA (_continued_)

PALPIGRADI—SOLIFUGAE = SOLPUGAE—CHERNETIDEA = PSEUDOSCORPIONES 422

CHAPTER XVII

ARACHNIDA EMBOLOBRANCHIATA (_continued_)

PODOGONA = RICINULEI—PHALANGIDEA = OPILIONES—HABITS—STRUCTURE—
CLASSIFICATION 439

CHAPTER XVIII

ARACHNIDA EMBOLOBRANCHIATA (_continued_)

ACARINA—HARVEST-BUGS—PARASITIC MITES—TICKS—SPINNING MITES—
STRUCTURE—METAMORPHOSIS—CLASSIFICATION 454

CHAPTER XIX

ARACHNIDA (APPENDIX I)

TARDIGRADA—OCCURRENCE—ECDYSIS—STRUCTURE—DEVELOPMENT—AFFINITIES—
BIOLOGY—DESICCATION—PARASITES—SYSTEMATIC 477

CHAPTER XX

ARACHNIDA (APPENDIX II)

PENTASTOMIDA—OCCURRENCE—ECONOMIC IMPORTANCE—STRUCTURE—DEVELOPMENT
AND LIFE-HISTORY—SYSTEMATIC 488

PYCNOGONIDA