FIGURES 198 AND 199 



198 Transverse section of middle thoracic region of 12 mm. cat embryo, 

 (series 217, slide XI, section 27 ( X 225. 



199 Same, section 28. 



1 Sympathetic nerve.- 



2 Intersegmental arteries. 



3 Right azygos vein, thoracic portion. 



6 Left azygos vein, thoracic portion. 



7 Aorta. 



34 Ventro-medial azygos plexus. 



