422 



The left sixth arch is large, and of somewhat greater size than 

 the right, and a separation has taken place in the truncus arteriosus 

 dividing the pulmonary from the aortic channel. The pulmonary 



"~', / ,-' 



Fig. 13. Reconstruction of Aortic arches in Pig embryo of 22nd (?) day. 

 X about 22. 



