FROM TWELVE TO THIRTY-SIX SOMITES 



163 





';-,_!^DJenc. 



3.J0. 



— ' — •'^-'^^^SsSt-- '■■--■ 



v5.2C 



^.27 





■— i/?//: 



^/77. 



r^.^y^ 



Fig. 93. — Entire embryo of 27 s viewed as a 



transparent object from above. 



a. a. 1, a. a. 2, a. a. 3, First, second, and third 

 aortic arches. Car., Carotid loop. Ret., Retina. 

 V. C. 1, V. C. 2, First and second visceral clefts. 

 Other abbreviations as before, x 20. 



