1 8 "Journal of Comparative Neurology and Psychology. 



sagittalis, the first of these names being the one which I shall 

 adopt. This unmedullated tract is not very compact, but large, 

 as shown in Fig. xxii, which shows that it constitutes a connection 

 between the dorsal and ventral layers of the fore-brain, running 

 medially through its posterior part. 



The dorsal group of cells where this tract originates is, however, 

 merely a median local enlargement of an important dorsal mass of 

 rather large cells, which, more distally, lies in the upper layers of 

 the lateral part of the pallium. In this region there originates an 

 important tract, the tractus pallii, which Edinger has already 

 described. It lies immediately under the dorsal surface of the 

 brain and is gradually made up of short groups of fibers which 

 come perpendicularly from the depths, as shown by Figs, xxi and 

 xxii. This flat but large bundle then goes on the outer surface 

 of the fore-brain toward its base, where, however, it always 

 remains lateral to the tractus strio-thalamicus, which is still to be 

 described. A decussation of the pallial bundle takes place in the 

 'tween-brain and will be treated in the next chapter. 



So, then, we have become acquainted with the following groups 

 of cells in the dorsal and lateral regions of the fore-brain: 



1. The area oljactoria posterior, which lies in the lateral part 

 of the fore-brain and must be regarded as the terminus of the 

 secondary olfactory tracts. As a special enlargement of this 

 region there lies dorsally: 



2. The nucleus olfactorius dorsalis, from which originate the 

 decussatio inter-hemispherica and the tractus medianus. 



3. More ventro-laterally situated we found the ending of the 

 decussatio inter-hemispherica in a group of cells which also 

 receives an uncrossed bundle from the same region where the 

 decussatio inter-hemispherica originates. The terminal nucleus 

 of these tracts I have called the epistriattim, by which is indicated 

 its situation directly adjacent to the striatum and the fact that it 

 belongs to the olfactory centers. 



4. The region where a part of the decussatio inter-hemi- 

 spherica terminates has already been described by Botazzi in 

 Mustelus; it forms the fourth dorsal group of cells, the regio 

 uncinata, by which the ventricle is partially obliterated. 



5. A more important dorsal center- is the place where there 

 originate medially the tractus cortico-medialis and laterally the 

 tractus pallii and which may be called the nucleus dorsalis pallii. 



