1 78 Journal of Comparative Neurology and Psychology. 



lie somewliat more deeply embedded in the nerviis olfactoriiis than 

 those of the left nerve. They curve dorsad and mesad before dis- 

 appearing, as on the other side. 



Passing caudad, the fila olfactoria enter the bulbus olfactorius, 

 but the fibers of the nervus terminalis separate from them ven- 

 trally and constitute a small compact bundle of fibers lying in the 

 meninges ventrally of the olfactory bulbs (Figs. 3 and 4). This 

 position is maintained until they have passed caudad of all of the 

 formatio bulbaris (glomerular formation) of the olfactory bulbs, 

 where they turn abruptly dorso-mesad and enter the substance of 

 the cerebral .hemisphere at its ventro-medial border. The point of 

 entrance of these fibers varies somewhat in different specimens. It 

 is in the adult aways farther caudad than any of the formatio bul- 

 baris of the ventral and medial aspects of the olfactory bulbs, and 

 in all but one of the observed cases farther caudad than the for- 

 matio bulbaris of the bulbulus accessorius on the lateral aspect of 

 the olfactory bulb. 



Having entered the brain, the nei-vus terminalis passes caudad 

 (Fig. 5), turning slightly dorsad and laterad in its course, embedded 

 in the ventral part of the hemisphere about midway between the 

 ventral border of the lateral ventricle and the medial wall of the 

 hemisphere. The fibers of the tractus olfactorius medialis lie ven- 

 trally and medially of it and those of the median forebrain bundle 

 dorsally of it. Upon reaching the lamina terminalis (Fig. 6), it 

 ascends more rapidly between the lateral forebrain bundle and the 

 crossed portion of the medial forebrain bundle to enter the middle 

 part of the anterior commissure complex dorsally of the pre-optic 

 recess, where it decussates (Fig. T). The fibers can be clearly 

 traced across the meson in a compact bundle, but their exact place 

 of termination has not been determined. These relations were con- 

 firmed in every detail in the transverse Weigert series, and in every- 

 thing except the decussation in the anterior commissure in the 

 sagittal Golgi series. 



In one of my series of transverse sections through the brain of 

 the adult R. pipiens prepared by the method of Cajal the nervus 

 terminalis can be followed in its course through the cerebral hemi- 



