FIGURES 198 AND 199 



198 Transverse section of middle tlioracic rejiion of 12 mm. cat embryo, 

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



199 Same, section 28. 



1 Sympatlictic nerve. 



2 Intersegmental arteries. 



3 Right azygos vein, thoracic portion. 



6 Left azygos vein, thoracic portion. 



7 Aorta. 



34 Ventro-medial azygos piexu.'^. 



