152 



NOSE 



FIG. 194. A, HEAD OF AN EMBRYO ABOUT THIRTY-FOUR DAYS OLD, FROM BELOW. B, THE ROOF OF 



THE PRIMITIVE MOUTH OF THE SAME EMBRYO AFTER REMOVAL OF THE MANDIBLE. (His.) 



i.m., placed on the fronto-nasal process, and just above its intermediate depressed part ; l.n.pr., lateral 

 nasal process; m.n.pr., mesial nasal process; other letters as in fig. 192. The nasal laminae of the 

 processus globular es and the palatine projections of the maxillary processes are seen in B. 



olfactory nerve-fibres 



septum 



v:.*;^,v--;.^-.c--:.viV;/,at.?t4:.-&iv->,vr.v^* 



ol. ves. 



inf. m. 



/ongue 



FIG. 195. SECTION THROUGH THE OLFACTORY VESICLES IN A HUMAN EMBRYO OF 15'5 MM. 



(T. H. Bryce.j 



ol.ves., olfactory vesicle : on the right the vesicle is still separated from the mouth by the bucco- 

 nasal membrane, b.n.m. ; on the left this membrane has disappeared, and the section passes through the 

 primitive choana ; J.o., groove which will become Jacobson's organ ; inf.m., groove which will become 

 the inferior meatus ; pal., palatal folds. 





