CONTENTS 



XIX 



PAGE 



{(l) From the Branchial Arches — 



7. Thymus . . . . .602 



8. Parathyreoids . .... 603 

 (e) From the Mesothelium of the Genital Ridge — 



9. Gonads . . . . .605 

 10. Inter-renals ..... 609 



The Interaction of the Endocriuetes . . .611 



The Mode of Action of the Internal Secretions . .611 



Protective Modifications of Metabolism — Immunity . . 612 



PART IV. 



THE ANIMAL AS PART OF THE SPECIES. 



A. Reproduction. 



I. Determination of Sex 

 II. The Gonads 



III. The Secondary Sexual Organs 



IV. The (Estrous Cycle 

 V. Impregnation 



617 

 618 

 621 

 622 

 623 



I. 



II. 



III. 



IV. 



V. 



VI. 



VII. 



VIII. 



B. Development. 



Early Stages of Development 

 Attachment of Embryo to Mother 

 The Nourishment of the Foetus 

 Growth of the Fcctus 

 Metabolism in Pregnancy 

 The Voung Animal at Birth 

 Foetal Circulation 

 Gestation and Delivery . 



IX. Lactation 

 Appendices 

 Index 



624 

 626 

 628 

 630 

 631 

 631 

 631 

 633 

 634 



641 



655 



