64 



CHARLES BROOKOVER 



placed cells of the capsule. At this time the olfactory nerve has a 

 large number of fibers and its length is equal to about half the 

 diameter of the olfactory cup (fig. 5). The fibers spread peri- 

 pherally, ramifying as small bundles among the cells of the cap- 

 sule. The thickness of the capsular epithelium is not so great 

 in the middle of the mesal side of the capsule. This is opposite 



-k ? 







X»th ar inr M,M ol 



Fig. 4. Horizontal section of Amia 6 hours after hatching. Shows two rami 

 of the olfactory nerve as it arises from the placode, the migrating placodal nuclei 

 and the fiber zone devoid of neuroblasts just inside the neural tube. Stain as 

 above. X 400. 



the middle of the spread of the fibers into the nasal capsule, and 

 causes the capsule to appear flattened laterally. The thin nasal 

 epithelium at this point has more nearly its adult character 

 than the epithelium at the margins of the capsule reached by the 

 laterally spreading olfactory fibers (fig. 5). Laterally where the 

 walls of the nasal capsule are thicker there are nuclei arranged 



