HUMAN EMBRYOLOGY AND MOEPHOLOGY. 



maxillary processes (Fig. 15 A) and lined by the covering 

 epithelium of the skin— epiblast. It is blind at first, the floor 



stomodaeum 

 max. proc. 



somatopteure 

 mandibular arch 



Fig. 15 A.— Sagittal Section showing the Stomodaeum and position of the Oral Plate 

 in the 3rd week. (Schematic.) 



Eustach. 

 (1st cleft). 



tonsil 

 (2nd cleft )f£ 



rom max. proc. 

 ■^position of oral plate . 



i'Yl I f rom man dib- P roc - 



Fig. 15 B.— Showing the parts of the Buccal and Nasal Cavities formed from the 

 Stomodaeum. The relative position of the Oral Plate is indicated. 



or fundus being formed by the oral plate, which separates it 

 from the primitive pharynx (Fig. 15.4). The mesial nasal 

 and palatal plates of the maxillary processes divide it into an upper 

 part — the nasal cavities — and a lower, which forms part 



