Fig 18 Transvci'sc section of m\ ciiiln-vo of twelve somites to sliow the 

 amniotic, position of the candal anlages of tlir uml:>ilical vein. Columliia ('ollec- 

 tion No. 547, slide 5, row 'J, section 7, X •il'O. Ueduceil \. 



1 TTmbilical an^liocyst I I'unnel-like diverticnhnn of eoelom 



2 .\mnion l)etw<'en vessels of tlu^ splanchno- 

 o .Mesosti'onia pleine 



73 



