38 'JoiirunJ of Comparative Neurology and Psychology. 



region of the lobi anteriores with its posterior parts without 

 decussation (Figs, xlvi to xlviii). 



(2) An equally short but stronger tract (Figs, xlviii, il) gathers 

 around the nucleus rotundus proprius and passes over into the 

 mass of cells situated immediately under this nucleus. I call this 

 the tractus rotundo-loharis, which has been already correctly 

 figured as far as its origin is concerned by Bellonci, to which, 

 however, no special name was given either by him or by David, 

 who gives an excellent figure of it without mentioning it. 



(3) The last intralobular connection is formed by the conimis- 

 sura supra-mfiujdibularis, or com. post-injundihularis. This very 

 slight commissure connects the subventricular as well as the supra- 

 ventricular parts of the inferior lobes (Fig. xlv). 



A few words now about the fifth group of our scheme, comprising 

 the tr. strio-thalamicus and tr. olfacto-lobaris lateralis et medialis. 



(i) As I have already given the course of the tractus strio- 

 thalamicus in the thalamus, I can now confine myself to the de- 

 scription of its ending in the lobi inferiores. Gradually the fibers 

 of this bundle pass more ventrally and toward the median line 

 from the nucleus pr^erotundus backward (Fig. xliv) and finally 

 lie close to the median line (Fig. xlvii). After this they bend 

 laterally at a sharp angle and end in the cell masses of the back 

 part of the lobus partly' in the nucleus rotundus but chiefly in the 

 nucleus subrotundus. The terminus of the tr. strio-thalamicus 

 is caudad to the ending of both tractus olfacto-lobares, the lateral 

 of which ends somewhat more caudad than the medial. 



(2) The tr. olfacto-lobaris lateralis ends at the point where the 

 tr. strio-thalamicus runs as a circular bundle along the nucleus 

 praerotundus (Fig. xlvi). This tract for the greater part ends 

 decussated, but not above the ventriculus lobi inf., like the tr. 

 strio-thalamicus, but below it. 



(3) Of this group of frontal tracts, the one which ends most 

 frontally is the tr. olfacto-lobaris medialis, which passing quite 

 sharply laterally under the tr. strio-thalamicus, terminates in front 

 of the nucleus rotundus, as represented in Figs, xliii and xliv. 



It now remains to describe the sixth group, containing the 

 caudal tracts of the lobi. 



(i) Tractus lobo-cerebellaris. The region of origin of this tract 

 extends over the whole pars posterior lobi. The fibers arise in 

 the center and gather chiefly in the upper lateral angle where the 



