PLATE 11 



EXPLANATION OF FIGURE 



22 Drawn from a reconstruction of a chick embryo of 6 days and 22 hours, 16 

 mm. (series no. 463). Ventral view. 



I , aorta 



£, dorsal aortic root 



3, aortic arch VI 



3a, pulmonary artery 



4, aortic arch IV 



5, celiac artery 



10, precardinal vein 



II, subclavian vein 

 1°2, duct of Cuvier 

 13, vertebral vein 



15, jugular lymph sac 



15a, thoracic duct 'approach' of jugular 

 lymph sac 



16, groups of developing blood cells 

 16a, groups of blood cells dorsal to 



aortic roots and arches 



17, rudiments of thoracic duct 



18, lymphatics along aortic arches 



19, lymphatics dorsal to aortic roots 

 and arches 



21, mesenteric lymphatics 



184 



