Fig. 24 Ventral view of right cerebrum of Troglodytes (chimpanzee) to show 

 intracranial course of N. terminalis. 



Fig. 25 Sagittal section of nasal chamber of man from Toldt, to indicate 

 extracranial course of N. terminalis drawn in from Brookover's description. 

 The septal nerve (Vomeronasal) practically parallels the course of the terminal 

 branches. The invading branches of the trigeminus are also shown. 



Fig. 26 Six diagrams illustrative of the translation of the chemical sense 

 organs of the neuroporic territory of Amphioxus, from the exposed position on 

 the surface of the head to the inclosed condition found in Bdellostoma where 

 they are housed in the 'nasal' chamber. A. Pre-Amphioxus stage with the hypo- 

 physial organ still outside of and in front of the buccal cavity. B. Amphioxus 

 stage with the hypophysial organ inside the buccal cavity, said organ being the 

 first of the apical territory to find protection. C. Post-Amphioxus stage in which 

 the overgrowth of the trigeminal structures has housed in the remainder of the 

 apical territory of the Amphioxus head. This apical region furnishes the nasal 

 septum together with the sensory structures associated with it in the nose of the 

 higher vertebrates. D. Bdellostoma stage in which a nasopharyngeal partition 

 has appeared partly separating nasal and buccal chambers, fl. Ventral view of 

 stage C. F. Ventral view of stage D. 



337 



IHE JOURNAL OF COMPARATIVK NEtJBOLOQy, VOL. 30, NO. 4. 



