FIGT'RK 1 



1 Transve^^^e section of 10 mm. cat embryo Cserios 111. slide \'III, section 4), 

 X 17")- -'I'opojrr.-iphical ])ifture of site of earliest lympliatie space development. 



1 Sympathetic iier\ c 



S Oesophagus, 



•is JA'ft postcaidiiial \ciii. 



69 Lungs. 



72 l{ight dorsal aorta. 



7:5 Left dorsal aorta. 



77 .Meseiidiymal intercellular I y.'iij)hatic aidages. 



7'^ f'oeloin. 



