148 ROLLO E. McCOTTER 



medial surface of the olfactory peduncle where it appears to enter 

 the brain substance some distance from the olfactory bulb. In 

 one specimen, however, instead of entering the brain wall on the 

 medial surface of the olfactory peduncle the nerve passed across 

 this surface and apparently entered on the ventral surface of the 

 peduncle. A few small filaments which seem to be connected 

 with the olfactory nerves join the nervus terminalis just after 

 its separation from the vomeronasal nerves. 



Upon microscopical examination of the specimen of the vomero- 

 nasal nerves and the nervus terminalis, stained in mass, there 

 were observed large oval, fusiform and cone-shaped nerve cells 

 with granular cytoplasm and large spherical nuclei with promi- 

 nent nucleoli. These cells were present in considerable numbers 

 and were found either grouped around the nerve or embedded 

 between its fibers causing a fusiform enlargement of the nervus 

 terminalis immediately after its fibers have separated from the 

 vomeronasal nerves. 



The examination of the transverse sections of the olfactory 

 bulb of the dog confirmed the above mentioned observations. 

 The vomeronasal nerves were easily recognized and followed to 

 the vomeronasal formation. The filaments of the nervus termi- 

 nalis can be seen separating from the vomeronasal nerves. A 

 group of ganglion cells enclosed in a capsule and attached to the 

 combined filaments was followed through eight consecutive sec- 

 tions. In this particular series, the filaments having been slightly 

 torn in the preparation of the block, the ner\'e could not be traced 

 into the brain substance. 



The vomeronasal ner\-es of the cat (fig. 2) course upward and 

 backward in three separate bundles on the medial surface of the 

 olfactory bulb to the caudal border of this surface where they 

 unite into a loose plexus and turn outward to end in the vomero- 

 nasal formation. Several small filaments separate from the above 

 mentioned plexus and unite into a single strand which courses 

 caudalward on the medial surface of the olfactory peduncle where 

 it apparently enters the brain substance in the region of the arcu- 

 ate fissure. The nervus terminalis gradually decreases in size from 

 its connection with the vomeronasal nerves to its termination 



