FIGURES 124 AND 125 



124 Same, section 5. 

 126 Same, section 6. 



3 Right precaval vein. 



4 Atrophying embryonal vein, forming kernel in interior of developing 



and replacing lymphatic space. 



5 Extraintimal or perivenous lymphatic space surrounding degenerat- 



ing embryonal vein. 



7 Aorta. 



9 Trachea. 



10 Pulmonary artery. 



18 Peritracheal venous plexus. 



22 Vagus. 



32 Ventral mediastinal venous plexus. 



