CONTENTS xiii 



The Outer Ear 560 



Anomalies 561 



References for Further Study 562 



CHAPTER XIX 



FOETAL MEMBRANES 563 



Foetal Membranes in Birds and Reptiles 563 



The Amnion 563 



The Yolk Sac 567 



The Allantois 570 



The Chorion or Serosa 571 



Fcetal Membranes in Mammals 571 



Amnion, Chorion, Yolk Sac, Allantois, Umbilical Cord 572 



Further Development of the Chorion 575 



The Fcetal Membranes in Man . . 579 



The Amnion 579 



The Yolk Sac 581 



The Allantois 582 



The Chorion and Decidua 583 



The Decidua Parietalis 587 



The Decidua Capsularis . 587 



The Decidua Basalis 588 



The Umbilical Cord 596 



The Expulsion of the Placenta and Membranes 598 



Anomalies 598 



References for Further Study 599 



CHAPTER XX 



TERATOGENESIS 601 



Malformations Involving More Than One Individual 601 



Classification, Description, Origin 601 



Symmetrical Duplicity 602 



Origin of Symmetrical Duplicity 607 



Asymmetrical Duplicity . 608 



Origin of Asymmetrical (Parasitic) Duplicity 610 



Malformations Involving One Individual 612 



Description, Origin 612 



Defects in the Region of Neural tube 612 



Origin of Malformations in the Region of Neural Tube. . . .615 

 Defects in Regions of the Face and Neck, and their Origin . .616 



Defects in the Thoracic and Abdominal Regions, and their Origin 618 



Causes Underlying the Origin of Monsters 620 



The Production of Duplicate (Polysomatous) Monsters . . ... . 621 



