xii CONTENTS 



CHAPTER VIII 



PAGE 

 THE FRESH-WATER MUSSEL 'CHARACTERS OF THE PHYLUM 



MOLLUSCA -ENUMERATION OF THE CHIEF PHYLA OF THE 



ANIMAL KINGDOM . 396 



PRACTICAL DIRECTIONS ^ I2 



CHAPTER IX 



CHARACTERS OF THE PHYLUM VERTEBRATA -THE LANCELET 418 



PRACTICAL DIRECTIONS 426 



CHAPTER X 



> 



CHARACTERS OF THE CLASS PISCES -THE DOGFISH .... 430 

 PRACTICAL DIRECTIONS 472 



CHAPTER XI 



CHARACTERS OF THE CLASS MAMMALIA -THE RABBIT . . 482 

 PRACTICAL DIRECTIONS . . 542 



CHAPTER XII 



THE MINUTE STRUCTURE OF CELLS -CELL-DIVISION -STRUC- 

 TURE OF THE OVUM -GAMETOGENESIS -(SPERMATO- 



GENESIS AND OOGENESIS) -MATURATION AND FERTILISA- 

 TION OF THE OVUM -DIFFERENT TYPES OF OVA AND OF 



SEGMENTATION -EFFECT OF FOOD-YOLK ON DEVELOP- 

 MENT 558 



PRACTICAL DIRECTIONS 575 



CHAPTER XIII 



DEVELOPMENT OF THE LANCELET I EARLY DEVELOPMENT OF 

 OTHER TYPES, INCLUDING THE CHICK AND RABBIT 



FORMATION OF THE CHIEF ORGANS OF VERTEBRATES, 

 AND OF THE AMNION, ALLANTOIS, AND PLACENTA . . . 577 

 PRACTICAL DIRECTIONS 615 



INDEX 619 



