FIGURP;S 270 AND 271 



270 Same, section 18. 



271 Transverse section of anterior thoracic region in R a 15.5 mm. cat embryo 

 (series 143, slide XII, section 22), X 200. 



1 Sympathetic nerve. 



2 Intersegmental arteries. 



3 Right azygos vein, thoracic portion. 



6 Left azygos vein, thoracic portion. 



7 Aorta. 



8 Oesophagus. 



15 Interazygos venous plexus. 



35 Thoracic duct, preazygos segment. 



36 Thoracic duct, azygos segment. 

 51 Mesenteric lymphatics. 



