FIGURE 154 



154 Transverse section through ventral portion of upper thoracic region in 

 a 20 mm. cat embryo (series 241, slide, XIX, section IS), X 225. 



3 Right jirecaval vein. 



7 Aorta. 



8 Oesophagus. 



9 Trachea. 



10 Pulmonary artery. 



IS Peritracheal venous plexus. 



22 Vagus. 



37 Broncho-mediastin.il iluct. 



