CONTENTS 



Introduction 5 



Part I. The development of the systemic lymphatic vessels in their relation 



to the blood-vascular system 9 



Historical review of theories of lymphatic development 10 



Material used in present investigation 16 



Comparison of haemal and lymphatic vascular development 19 



Ontogeny of mammalian systemic lymphatic vessels 24 



Mutual relations of developing systemic lymphatic vessels and em- 

 bryonic veins 27 



Phylogenetic relations of the abdominal veins and axial lymphatics in 



mammals 33 



Development of systemic lymphatic vessels in the mammal independ- 

 ent of topographical association with embryonal veins 49 



Summary and conclusions of Part I 53 



Figs. 1 to 28 



Part II. The development of the preazygos and azygos segments of the thor- 

 acic ducts 55 



1. The thoracic duct approach of the jugular lymph sacs 60 



Figs 29 to 91. 



2. The preazygos segment 83 



Adult conditions 84 



Figs. 92 to 99. 



A. The development of the broncho-mediastinal trunk 91 



Figs. 100 to 158. 



B. The development of the preazygos segment of the thoracic duct 107 



Figs. 159 to 169. 



C. Junction of preazygos segment of thoracic duct and broncho- 



mediastinal trunk with each other and with the thoracic duct 



approach of the jugular lymph sac 113 



Figs. 170 to 187. 



3. Azygos segment 121 



A. General analysis of the development of the thoracic duct in the 



azygos region 123 



Figs. 188 to 193. 



B. Detailed consideration of the individual stages in the development 



of the azygos segment of the thoracic duct 129 



Junction of azygos and preazygos segments of the thoracic duct 150 



Figs. 194 to 275. 



Summary and conclusions of Part II 153 



