FIGURES 160 AND 161 



160 Transverse section of dorsal portion of upper thoracic region in a 13.5 cat 

 embryo (series 189, slide VII, section 20), X 225. 



161 Same, section 21. 



1 Sympathetic nerve. 



16 Dorso-medial somatic venous tributaries. 



17 Prevertebral venous plexus. 

 22. Vagus. 



25 Internal jugular vein. 



77 Mesenchymal intercellular lymphatic anlages. 



