CONTENTS 



CHAPTER I 



INTRODUCTION 



Scope of Embryology Growth, maturation, and conjugation of the germ-cells Sex- 

 chromosomes and their bearing on theories of heredity Recapitulation theory 

 of development and the evidence in its favour Embryonic and larval phases of 

 development and their mutual relationship Factors modifying the course of 

 development ........ Page 1 



CHAPTER II 

 PRACTICAL HINTS 



Methods of preserving embryos Methods of embedding embryo for section- 

 cutting and of orientating them so that the sections shall be cut in a known 

 direction ........ Page 32 



CHAPTER III 



PORIFERA 



The development of Sycandra raphanus as a type of the Calcarea : the Blastula, 

 Amphiblastula, and Ascon stages in its development The development of other 

 sponges (Oscarella, Plakina, Esperia, Spongilla, Clathrina, Leucosolenia) 

 The development of the gemmule of Ephydatia The ancestral history of 

 sponges . . , . . . . . . Page 37 



CHAPTER IV 



COELENTERATA 



The development of Tubularia as a type of the Hydrozoa The development of the 

 eggs of free-swimming medusae The development of the gonophore of Tubularia 

 and of the medusa of Podocoryne Other gonophores The development of 

 Siphonophora, Narcomedusae, and Trachymedusae The development of Aurelia 

 as a type of the Scyphozoa The development of Pelagia The development of 

 Urticina as a type of the Actinozoa -The development of Actinia bermudensis 

 The larvae of Zoanthidae and Cereanthidae The development of Alcyonaria The 

 development of the skeleton of Caryophyllia The development of Beroe as a type 



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