Fig. 27 Transverse section of an embryo of eight somites, Columbia Collec- 

 tion 530, slide 7, row 4, section 4, X 300. Reduced \. 



1 Aorta 



2 Coelom 



3 Omphalomesenteric plexus 



4 Projections of mesoderm between 

 blood vessels 



86 



