Herrick, ISfervLis Termirialis of Frog. 17 



k-iig, stained with Delafield's liaMiiatoxylin and erjthrosiu (Fig. 

 8). ^ ^ 



In these five specimens all, or nearly all, of the intra-cerebral 

 course of this nerve was followed on both the right and the left 

 sides. In several other specimens, both larval and adnlt, smaller 

 portions of the nerve were also seen. For all of the sections on 

 which this work is based I am indebted to the skill of my assistant, 

 ]\Ir. P. S. McKibben. The findings are briefly these. 



In the series of transverse sections made by the Golgi method 

 through the brain of the adult frog first referred to, at the level 

 of the olfactory bulbs (Figs. 3 and 4), there is impregnated a com- 

 pact fascicle of a few (probably less than 40) unmedullated nerve 

 fibers on each side, lying between the meninges and the ventral 

 surfaces of the olfactory bulbs. This is the nervus terminalis. 

 When followed caudad the nerves of the right and left sides are 

 found to be similar; but rostrad they exhibit slight differences. 



On the left side at the extreme rostral end of the olfactory bulb 

 the nervus terminalis has separated from the meninges and joined 

 one of the small fascicles of fila olfactoria on the ventral border 

 or the nervus olfactorius (Fig. 2). None of the fila olfactoria 

 of this fascicle are impregnated, so that it is easy to follow the 

 nervus terminalis separately on this side. Scattered fila olfactoria 

 are impregnated in other parts of the nervus olfactorius and these 

 are indistinguishable in appearance from the fibers of the nervus 

 terminalis. Less than 1 mm. rostrad of the olfactory bulb (Fig. 

 1) the nervus terminalis passes from the ventral to the medial 

 aspect of the nervus olfactorius, still embedded in its marginal 

 layer, and here it disappears from view. At about this level the 

 impregnated fila olfactoria also lose their stain, so that it is prob- 

 a})le that the nervus terminalis continues farther rostrad in the 

 nervus olfactorius, though its fibers are not farther impregnated 

 in my preparations. 



On the right side the relations are essentially the same, but not 

 so clearly demonstrable ou account of the fact that impregnated 

 fila olfactoria mingle in some places with the fibers of the nervus 

 terminalis- and the latter is not so compact a fascicle. Its fibers 



