THE BRANCHIAL REGION 



69 



tween the globular processes forms the lower part of the nasal septum or 

 columella; while above this is seen a prominent angle, which becomes the future 

 apex (Figs. 45, 46), and still higher a flat area, the future bridge, of the nose. 

 The lateral nasal processes form the alse of the nose. 



Continuous with the dorsal end of the mandibular arch, and growing forward 

 from its cephalic border, is a triangular process, the maxillary process, the ventral 

 extremity of which is separated from the mandibular arch by a > shaped notch 



Nares 



Primitive 

 palate 



Nasal 

 cavity 



FIG. 49. Primitive palate of a human embryo of thirty-seven to thirty-eight days. (From model by Peters.) 

 On the left side the lateral wall of the nasal cavity has been removed. 



Fig. 44). The maxillary process forms the lateral wall and floor of the orbit, 

 and in it are ossified the zygomatic bone and the greater part of the maxilla; it 

 meets with the lateral nasal process, from which, however, it is separated for a 

 time by a groove, the naso-optic furrow, that extends from the furrow encircling 

 the eyeball to the olfactory pit. The maxillary processes ultimately fuse with the 

 lateral nasal and globular processes, and form the lateral parts of the upper lip 



Globular process 



Mouth of olfactory 

 pit, or naris 



Palatine process of 

 globular process 



Palatine part of 

 maxillary process 



Maxillary process 



Lens 



Eye 



Pharynx 



FIG. 50. The roof of the mouth of a human embryo, aged about two and a half months, showing the mode of 



formation of the palate. (His.) 



and the posterior boundaries of the nares (Figs. 47, 48). From the third to 

 the fifth month the nares are filled by masses of epithelium, on the breaking down 

 and disappearance of which the permanent openings are produced. The maxillary 

 process also gives rise to the lower portion of the lateral wall of the nasal cavity. 

 The roof of the nose and the remaining parts of the lateral wall, viz., the ethmoidal 

 labyrinth, the inferior nasal concha, the lateral cartilage, and the lateral crus of 

 the alar cartilage, are developed in the lateral nasal process. By the fusion of the 



