Bedford, Olfactory Nei-ve in Siuvie. 



401 



veloping nerve cells are seen to be located at different levels 

 within the epithelium. B and B' , Fig. 6, represent neuro- 

 blasts whose cell bodies are located upon the margin of the 

 epithelium bordering the lumen of the nasal pit. N, Figs. 4, 



Ftg. 6. A, Sagittal section through head of an embryo 17 millimeters in 

 length. Br., wall of forebrain. X S. B, Portion of olfactory epithelium 

 (X 933^) indicated in A^ by brace (x), showing developing nerve cells (A'') and 

 supporting cells (5). A' represents a neuroblast that has migrated partially in- 

 to the mesoderm. GoLGl preparation. 



Fig. 7. Developing nerve cells from the 

 olfactory epithelium of a 15 mm. swine embryo, 

 one with central process directed into an elevation 

 of the epithelium. AL P., Nasal pit. X 140. 

 GoLGi preparation. 



5 and 6 represents developing nerve cells whose cell bodies are 

 considerably removed from the margin of the epithelium bor- 

 dering the lumen of the pit. N', Figs. 4 and 5 represents 

 nerve cells whose cell bodies are located nearer the mesodermal 

 margin of the epithelium. A' of Fig. 6 represents a develop- 

 ing nerve cell that is partially outside of the olfactory epithe- 

 lium, lying partially within the mosoderm. The Golgi prep- 

 arations were made from embryos of thirteen millimeters and 

 upward in length, 



Begimitng of Outgrowth from the Nasal Epithelium to- 

 zvard the Brain Wall. — In embryos from nine to twelve milli- 

 meters in length, the median wall of the olfactory pit becomes 

 relatively thicker than the lateral wall. At the same time, the 



