68 



EMBRYOLOGY 



the olfactory pits, which indent the fronto-nasal process and divide it into a, 

 medial and two lateral nasal processes (Fig. 45). The rounded lateral angles of 

 the medial process constitute the globular processes of His. The olfactory pits form 





Future apex of nose 

 Medial nasal process 



Olfactory pit 

 Lateral nasal process 

 Glcbular process 

 Maxillary process 

 Stomodeum 

 Mandibular arch 



Future apex of nose 



Medial nasal process 

 Olfactory pit 

 Lateral nasal process 



Globular process 

 Maxillary process 



Rocf of pharynx 

 Hypophyseal diverticulum 

 Dorsal wall of pharynx 



Fia. 45. Head end of human embryo of about thirty 

 to thirty-one days. (From model by Peters.) 



Fio. 46. Same embryo as shown in Fig. 45, with front 

 wall of pharynx removed. 



the rudiments of the nasal cavities, and from their ectodermal lining the epithe- 

 lium of the nasal cavities, with the exception of that of the inferior meatuses, is 

 derived. The globular processes are prolonged backward as plates, termed the nasal 

 laminae : these laminae are at first some distance apart, but, gradually approach- 



Lateral nasal pro- 

 cess 

 Globular processes 



FIG. 47. Head of a human embryo of 

 about eight weeks, in which the nose and 

 mouth are formed. (His.) 



Fio. 48. Diagram showing the regions of the adult face and neck 

 related to the fronto-nasal process and the branchial arches. 



ing, they ultimately fuse and form the nasal septum; the processes themselves 

 meet in the middle line, and form the premaxilla? and the philtrum or central 

 part of the upper lip (Fig. 48). The depressed part of the medial nasal process 



