CONTENTS. 



MM 



PREFACE, 3 



INTRODUCTION : THE GENERAL PRINCIPLES OF BIOLOGY, . 9 



CHAP. I. THE DISTINCTIVE CHARACTERS OF ANIMALS, . ... 44 



II. THE PROTOZOA, 78 



III. THE PORIFERA AND THE CffiLENTERATA, 102 



IV. THE TURBELLARIA, THE ROTIFERA, THE TREMATODA, AND Tmt 



CESTOIDEA, 157 



V. THE HIRUDINEA, THE OLIGOCH.ETA, THE POLYCH^TA, THE 



GEPHYREA, 189 



VI. THE ARTHROPOD A, 219 



VII. THE AIR-BREATHING ARTHROPOD A, 820 



VIIL THE POLYZOA, THE BRACHIOPODA, AND THE MOLLUSCA, . . 389 



IX. THE ECHINODERMATA, 466 



X. THE TUNIC ATA OR ASCIDIOIDA, 510 



XL THE PERIPATIDEA, THE MYZOSTOMATA, THE EXTEROPNEDSTA, 

 THE CH.ETOGNATHA, THE NEMATOIDEA, THE PHYSEMARIA, 



THE ACANTHOCEPHALA, AND THE DlCYEMIDA, . . . 584 



XH. THE TAXONOMY OF INVERTEBRATED ANIMALS, .... 561 

 INDEX, 589 



