FIGURES 10 AND 11 



10 Transverse section of anterior thoracic region of 12 mm. cat embryo (series 

 "217, slide X. seetion 12). X 225 — showing early extraintimal lymphatic develop- 

 nienl. 



1 1 Transver.se .section of anterior thoracic region in a 12 mm. cat embryo (series 

 211, slide X. seetion l.">). X 225. 



■^ riccaiilinal or precava. resp. azygos of right side. 

 I At ropliying einhryonal vein, forming kernel in interior of developing 



and replaeing lymphatic space. 

 5 Kxtraintinial or perivenous lymphatic space surrounding degenerating 



einhryonal vein. 

 <> I'recardinal or i)recava, resp. azygos of left side. 

 7 -Vorta. 

 S Oesopji.-itius 

 !» Trachea. 

 Id i'lihnonary artery. 

 22 Vagus. 



