NERVUS TERMINALIS: MAMMALS 21 



fixation over night in amnioniuni-picrate, the mucosa was re- 

 moved from the bony septum and was mounted whole. This 

 was done with the mucosa from both sides of the septum. The 

 two sides showed essentially the same- picture, but the right 

 side was somewhat clearer, and is illustrated in figure 4. 



In this specimen the vomeronasal nerves {n.vom.) consist of 

 three principal bundles in their proximal course on the septum. 

 About midway toward the organ of Jacobson, which could not 

 be removed with the mucosa without too great danger of injury 

 to the latter, two of these bundles divide into secondary strands. 

 These strands continue to the vomeronasal organ. Parallel 

 with the vomeronasal bundles and in close proximity to them 

 for some distance are the main strands of the nervus terminalis. 

 These strands pass through the cribriform plate, as previously 

 shown in the dissections and as verified by pyridin-silver prepa- 

 rations, in company with the vomeronasal bundles. They con- 

 tinue parallel with them for some distance (fig. 4, n.ter.) and 

 then divide, forming an intricate plexus in the deeper part of 

 the mucosa (fig. 4, p.pL). Comparison with silver preparations 

 of the nasal septum makes it evident that only a portion of the 

 plexus was stained in this specimen. This portion was- derived 

 chiefly from the most dorsal (d.n.ter.) of the principal terminalis 

 strands present. The median of these strands (m.n.ter.) gives 

 off some small twigs of fibers which anastomose with the main 

 trunk of the dorsal bundle, and more rostrad it breaks up into 

 branches, one of which (r.nied.) forms a portion of the plexus. 

 A larger branch of this median bundle continues parallel with 

 the median branch of the vomeronasal bundle, but could be fol- 

 lowed for only a short distance rostrally. The most ventral 

 bundle of the terminalis (v.n.ter.), which is also the largest, was 

 lost distally because of the idiosyncrasy of the stain. A small 

 twig (r. ven.) given off in the more proximal part of its course 

 passes beneath the ventral vomeronasal bundle and is soon lost 

 in the mucosa ventral to this bundle. A large branch (r.dor.) 

 from the dorsal terminalis bundle also courses ventrally, but 

 this could not be traced beyond the dorsal ramus of the ventral 

 vomeronasal bundle. All other branches which were stained 



