CONTENTS ( 



XIII. The thirteenth day. Stages 34 and 35 164 



The first half of the thirteenth day. 



Stage 34. External distinctive features. The abdominal, epi- 

 gastric, and umbilical veins. The diaphragm. The perineum. 

 The oral shield. The palate. Mammary anlagen. Connection 

 between thoracic duct and jugular sacs. Miscellaneous details. 

 The second half of the thirteenth day. 



Stage 35. External distinctive features. The gestation period. 

 Parturition. The migration to the pouch. The negative geo- 

 tropism. The attachment to the nipple. The respiratory 

 bronchioles. The intranarial epiglottis and the pumping of 

 milk. The 'tubular' muscle fibers. Testis cords and the urino- 

 genital organs. 'The heart and the cardiac veins. The stomach 

 and the intestines. The sensory organs. The cisterna chyli. 

 The auditory ossicles. Miscellaneous details. 



XIV. Appendix 198 



Postnatal development. Some experimental techniques. The 



evolution of the mammals. 

 Bibliography 210 



