FIGURE 14S 



148 Transverse section throu<!;h ventral portion of upper thoracic region in 

 a 16 mm. cat embryo (series 222, slide X, section 2), X 225. 



1 Sym])alhet ic nerve. 



3 Right Azj'gos vein, thoracic jjortion. 



(i Precardinal or jirecava of left side. 



7 Aorta. 



8 Oesophagus. 



9 Trachea. 



10 Pulmonary artery. 



22 Vagus. 



36 Thoracic duct, azygos segment. 



37 Bi-(tnclio-iiicdiastinal duct. 



