FROM TWELVE TO THIRTY-SIX SOMITES 163 



Metenc 7st/i. cr.fj. 



"'' .^@""\ 



Md. VSy' 



K/i J ''- 





S.2. 

 D.C. 



S.27 





FIG. 93. Entire embryo of 27s viewed as a 

 transparent object from above. W 



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. 



