Chapter I: Preface: To the Mollusca

The general plan of classification adopted in this work is not that of any single authority. It has been thought better to adopt the views of recognised leading specialists in the various groups, and thus place before the reader the combined results of recent investigation. This method may, perhaps, occasion a certain number of small discrepancies, but it is believed that the ultimate effect will be to the advantage of the student.

The classification adopted for the recent Cephalopoda is that of Hoyle (‘Challenger’ Reports, _Zoology_, vol. xvi.), for the fossil Cephalopoda (Nautiloidea) that of Foord (_Catalogue of the Fossil Cephalopoda in the British Museum_, 1888–91), and (Ammonoidea) P. Fischer (_Manuel de Conchyliologie_, 1887). In the Gasteropoda the outlines are those adopted by Pelseneer (_Mém. Soc. Malacol. Belg._ xxvii. 1894), while the details are derived, in the main, from P. Fischer. The Amphineura, however, have not been regarded as a separate class. The grouping of the Nudibranchiata is that of Bergh (Semper, _Reisen im Archipel der Philippinen_, ii. 3). The Pelecypoda are classified according to Pelseneer’s most recent grouping.

Acknowledgment of the principal sources of information has been made in footnotes, and a short list of leading authorities has been appended to the chapters on anatomy, for the use of students desirous to pursue the subject further. In the case of geographical distribution the authorities are too numerous and scattered to admit of a list being given.

A special word of thanks is due to Mr. Edwin Wilson for his patient care in preparing the illustrations, the majority of which are taken from specimens in the University Museum of Zoology. Mr. Edgar Smith, besides affording the kind help which visitors to the British Museum always experience at his hands, has permitted me to use many specimens for the purposes of illustration.

A. H. COOKE.

KING’S COLLEGE, CAMBRIDGE,
_20th December 1894_.

CONTENTS

SCHEME OF THE CLASSIFICATION ADOPTED IN THIS BOOK.

MOLLUSCA

CHAPTER I

INTRODUCTION--POSITION OF MOLLUSCA IN THE ANIMAL
KINGDOM--CLASSIFICATION--ORIGIN OF LAND AND FRESH-WATER
MOLLUSCA 1

CHAPTER II

LAND AND FRESH-WATER MOLLUSCA, THEIR HABITS AND GENERAL
ECONOMY 23

CHAPTER III

ENEMIES OF THE MOLLUSCA--MEANS OF DEFENCE--MIMICRY AND
PROTECTIVE COLORATION--PARASITIC
MOLLUSCA--COMMENSALISM--VARIATION 56

CHAPTER IV

USES OF SHELLS FOR MONEY, ORNAMENT, AND FOOD--CULTIVATION
OF THE OYSTER, MUSSEL, AND SNAIL--SNAILS AS
MEDICINE--PRICES GIVEN FOR SHELLS 96

CHAPTER V

REPRODUCTION--DEPOSITION OF EGGS--DEVELOPMENT OF THE
FERTILISED OVUM--DIFFERENCES OF SEX--DIOECIOUS AND
HERMAPHRODITE MOLLUSCA--DEVELOPMENT OF FRESH-WATER
BIVALVES 123

CHAPTER VI

RESPIRATION AND CIRCULATION--THE MANTLE 150

CHAPTER VII

ORGANS OF SENSE: TOUCH, SIGHT, SMELL, HEARING--THE
FOOT--THE NERVOUS SYSTEM 177

CHAPTER VIII

THE DIGESTIVE ORGANS, JAW, AND RADULA: EXCRETORY ORGANS 209

CHAPTER IX

THE SHELL, ITS FORM, COMPOSITION, AND GROWTH--DESIGNATION
OF ITS VARIOUS PARTS 244

CHAPTER X

GEOGRAPHICAL DISTRIBUTION OF LAND AND FRESH-WATER
MOLLUSCA--THE PALAEARCTIC, ORIENTAL, AND
AUSTRALASIAN REGIONS 277

CHAPTER XI

GEOGRAPHICAL DISTRIBUTION OF LAND MOLLUSCA
(_continued_)--THE ETHIOPIAN, NEARCTIC, AND
NEOTROPICAL REGIONS 328

CHAPTER XII

DISTRIBUTION OF MARINE MOLLUSCA--DEEP-SEA MOLLUSCA AND
THEIR CHARACTERISTICS 360

CHAPTER XIII

CLASS CEPHALOPODA 378

CHAPTER XIV

CLASS GASTEROPODA--AMPHINEURA AND PROSOBRANCHIATA 400

CHAPTER XV

CLASS GASTEROPODA (_continued_): OPISTHOBRANCHIATA AND
PULMONATA 427

CHAPTER XVI

CLASSES SCAPHOPODA AND PELECYPODA 444

BRACHIOPODA (RECENT)

CHAPTER XVII

INTRODUCTION--SHELL--BODY--DIGESTIVE SYSTEM--BODY
CAVITY--CIRCULATORY SYSTEM--EXCRETORY
ORGANS--MUSCLES--NERVOUS SYSTEM--REPRODUCTIVE
SYSTEM--EMBRYOLOGY--HABITS--DISTRIBUTION--CLASSIFICATION
463

BRACHIOPODA (FOSSIL)

CHAPTER XVIII