306 ALBERT KUNTZ 



2. The author finds, however, that the cells giving rise to the 

 sympathetic trunks are not derived exclusively from the spinal 

 ganglia, as His, Jr., supposes, but that they are derived, wholly 

 or in part, from the neural tube. Medullary cells migrate from 

 the neural tube into the ventral roots of the spinal nerves. With 

 similar cells which wander out from the spinal ganglia, these cells 

 migrate peripherally along the spinal nerves. At a point a little 

 above the level of the aorta, cells deviate from the course of the 

 spinal nerves and, migrating toward the aorta, give rise to the 

 primary sympathetic trunks. As migration proceeds, the cells 

 which deviate from the course of the spinal nerves no longer 

 wander into the primary sympathetic trunks, but become aggre- 

 gated at the point of origin of the communicating rami and give 

 rise to the anlagen of the secondary sympathetic trunks. 



3. The prevertebral plexuses arise as cell-aggregates lying along 

 the ventro-lateral aspects of the aorta from the suprarenals pos- 

 teriorly. They are derived directly from the primary sympa- 

 thetic trunks. 



4. The ganglion of Remak arises as an oval cell-column lying 

 in the mesentery just dorsal to the rectum. It arises from cells 

 which the author finds to migrate ventrally from the hypogastric 

 plexus. 



5. The cardiac plexus and the sympathetic plexuses in the walls 

 of the visceral organs, which the author has designated as the 

 " vagal sympathetic" plexuses in an earlier paper, arise from cells 

 which migrate from the hind-brain and the vagus ganglia along 

 the fibers of the vagi. In the posterior region of the intestine, 

 the myenteric and the submucous plexuses probably receive some 

 cells from the ganglion of Remak. 



6. The cells which migrate from the neural tube and from the 

 cerebro-spinal ganglia along the spinal nerves and the vagi are 

 the descendants of the "germinal" cells of His; viz., the "indiffer- 



