296 



LEIGH HOADLEY. 



surrounding it. In the thickened .ire. is, however, the boundary 

 becomes indistinct, and in many plures, cells may be seen which 

 appear to be migrating from the epithelial layer into the mesen- 

 chyme. These areas represent the sensory epithelium and from 

 them the olfactory nerve arises. A short distance from the nasal 



FIG. 6. Cross section of graft of nasal region of chick embryo of thirty-six 

 hours of incubation, 41 B i. (X 140.) All., allantoic border of membrane sur- 

 rounding graft. B.C., blood corpuscles. Br., brain. Epderm., epidermis. Mesen., 

 host mesenchyme. N.Epith., nasal epithelium. .V.5., nasal sacs. Nas.Cart., 

 prenasal cartilage. O//..V., olfactory nerve. 



epithelium may be seen a small group of ganglion-like' cells 

 (Marshall, 1879) and toward these the nerve cells appr.n to be 

 migrating. From the ganglionic group, nerve hlu-r bundles o>n- 



