Plate L 



Fig. 31. Reconstruction of the ectal surface of the epithehum of the left buccal 

 sulcus in a 13 millimeter embrj'o. Columbia Collection, No. 107, X 300. 

 Dorsal view, reduced to 5. 



la. Secondary buccal sulcus. 

 2. Angulus oris. 



4. Postangular bend. 



7. Orbital inclusion, pars lata. 



5. Orbital inclusion, pars cylindrica. 

 //. Separating sulcus. 



12. Parotid anlage. 



15. Orbitoparotid interval. 



