424 'Journal of Comparative Neurology and Psychology. 



Fig. 3. Section a little farther cephalad than the last. At this level the funiculus dorsalis has been 

 almost entirely replaced by the spinal V tract and the fasciculus dorso-lateralis has begun to move 

 upward along the outer side of the spinal V tract to reach the lateral funicular nucleus farther cephalad. 

 Extensive tracts also pass from this fasciculus inward to reach the median funicular nucleus and forma- 

 tio reticularis. Bundles of secondary fibers appear between the spinal V nucleus and the median funic- 

 ular nucleus, which pass downward into the formatio reticularis. The dorsal commissure has con- 

 siderably enlarged, its fibers passing chiefly between the formatio reticularis of the two sides. From 

 this point cephalad this commissure is known as the commissura infima Halleri. In the dorso-lateral 

 fasciculus there is a separate bundle, designated x in Figs. 3 and 4, which ascends into the oblongata 

 beyond the level of the funicular nuclei, joining itself to the ventral part of the spinal V tract. I have 

 designated it provisionally the tractus spino-cerebellaris. The most dorsal part of the fasciculus is desig- 

 nated w and termed tractus bulbo-spinalis. It arises in the lateral part of the formatio reticularis 

 in the region of the funicular nuclei (Figs. 6 and 5), and appears to be a descending tract for the 

 spinal cord. X 35- 



com.inf., somatic part of commissura infima; f.d.L, fasciculus dorso-lateralis; /./., fasciculus lateralis; 

 f.l.m., fasciculus longitudinalis medialis; f.r., formatio reticularis; f.v., fasciculus ventralis; n.fn.m., 

 median funicular nucleus; n.5/>.r., spinal V nucleus; j., secondary tracts from spinal V nucleus and 

 median funicular nucleus; sp. V. tr., spinal V tract; tr.sp. tect., tractus spino-tectalis (lemniscus); w., 

 tractus bulbo-spinalis; *■., tractus spino-cerebellaris y., secondary tracts from lateral funicular nucleus 

 (c/. Fig. 4). 



Fig. 4. Section through the funicular nuclei at their widest part. The lateral funicular nucleus 

 appears external to the spinal V tract and its nucleus, receiving many fibers from the fasciculus dorso- 

 lateralis and sending large tracts to the formatio reticularis and the commissura infima. This com- 

 missure receives also a large mass of fibers from the median funicular nucleus and probably also from 

 the spinal V nucleus. This section shows the somatic portion of the commissura infima at its greatest 

 extent. Fibers are seen passing from the spinal V tract into its nucleus, and some pass through this 

 nucleus to end in the median funicular nucleus. X 35- 



com.inf., somatic part of commissura infima; f.d.L, fasciculus dorso-lateralis; /./., fasciculus lateralis; 

 f.l.m., fasciculus longitudinalis medialis; /.r., formatio reticularis; /.i'., fasciculus ventralis; n.cmh., caudal 

 end of nucleus ambiguus; n.fn.l., lateral funicular nucleus; n.fn.m., median funicular nucleus; n.sp.V., 

 spinal V nucleus; s., secondary tracts from spinal V nucleus and median funicular nucleus; sp.V.tr., 

 spinal V tract; tr.sp.h.tect., tractus spino- et bulbo-tectalis (lemniscus); w., tractus bulbo-spinalis; x., 

 tractus spino-cerebellaris; y., secondary tracts from lateral funicular nucleus. 



