NERVUS TERMINALIS IN REPTILE AND MAMMAL 103 



of them more medially and in contact with one another, the 

 third twelve sections farther laterally. The three roots uniie 

 upon the ventro-medial surface of the olfactory nerve and there 

 enter a distinct small ovoid or pear-shaped ganglion terminale. 

 From the distal border of this ganglion go off strands of nerve 

 fibers which mingle with those strands of the olfactory nerve 

 which run down in the nasal septum. The ganglion terminale 

 is closely connected distally with these olfactory strands, which 

 present the appearance of a network, and the nervus terminalis 

 is lost at this point.' 



On the left side in this embryo only one root was seen, the 

 ganglion was somewhat more diffuse and more intimately con- 

 nected with the olfactory strands in the septum. 



Two other embryos in the Huber collection, vi and xxxiii, 

 each between 15 and 16 mm. in length, show the nervus termi- 

 nalis, but less clearly than the 31 mm. embryo. A drawing from 

 one of them is given in figure 7. The ganglion cells do not show 

 as clearly in these sections as in the writer's embryo of the same 

 stage (H. 16), but they supplement the latter by showing the 

 root in the usual position. 



A fourth embryo in the Huber collection, ixl, 47 mm., shows 

 the relations of the nervus terminalis clearly. It arises from the 

 hemisphere just caudal to the olfactory bulb (fig. 8), passes 

 rostrad ventro-medial to the bulb, comes in contact with the 

 rostromedial surface of the 'olfactory ganglion' on the distal end 

 of the bulb, and then joins the strands of the olfactory nerve so 

 that it could not be followed farther. 



It should be emphasized that in both the 31 mm. and 47 mm. 

 embryos it is perfectly clear that the nervus terminalis joins with 

 numerous strands of the olfactory nerve to make up the network 

 of nerve bundles in the septum nasale. The writer was unable 

 to demonstrate that the nervus terminalis was restricted to the 

 immediate vicinity of the vomero-nasal organ as is the case in 

 the pig. 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 23, NO. 2 



