Fig. 2'J Ventral view of a model of Ihe luesodcviu twliitc), splanchnopleuric 

 mesenchyme (green), vasofactive cells (yellow) and endothelium (red) of an 

 embryo of two soniit<<s. 2, Anlages of dorsal aorta: 3, First intersomitic cleft; 

 4. second intrrsomitic cleft. 



78 



