( 93) 



If one will call lliis part of the chord hoinolog;ons to the Nerviis 

 sphiiieiiiiicns major of phicental inanunals, it must be pointed out 

 that in this group llie Nervus splanehnicus is the entire sympathetic 

 nerve. So the segmental caudal limit of this nerve falls in the region 

 of the thirteenth or fourteenth thoracic nerve. 



In the abdominal part some difïerences appear between Echidna 

 and Ornithorhynchus. In the former the sympathetic nerve divides 

 under the diaphragm into two branches of very unequal dimension. 

 The larger of the two passes in medial direction and disappears in 

 the corpus suprarenale (Fig. J g. s. r.) after having sent some small 

 branches to the kidney. The second, much smaller branch passes in 

 caudal direction and is the continuation of the sympathetic chord. 



Into the latter tirst passes a branch, springing from the sympathetic 

 ganglion of the fourteenth thoracic nerve, after that the rami viscerales 

 of the succeeding thoracolumbar nerves. 



In Ornithorhynchus the sympathetic chord passes under the dia- 

 phragm into an oblong ganglion. From the medial side of this some 

 fibres arise, that pass to the suprarenal body (Fig. 2 g. s. r.) and 

 the kidney (Fig. 2 n.). With this ganglion communicate moreover 

 the rami viscerales of the sixteenth and partly that of the seventeenth 

 thoracic nerve. 



In Ornithorhynchus 1 did not find a ran uis visceralis of the fifteenth 

 thoracic nerve. 



In Echidna there were separated ganglia where the rami viscerales 

 of the fifteenth and sixteenth thoracic nerves join the sympathetic 

 nerve. A ganglion splanchnicum (Arnold), which occurs in mammals 

 in the course of the Nervus splanehnicus major, Monotremes do not 

 possess. Probably this ganglion is still contained in the corpus supra- 

 renale ; this organ we may therefore call in these animals "ganglion 

 suprarenale". 



Following the sympathetic nerve further in the abdomen we see 

 that it receives the rami viscerales of the nerves in regularly arranged 

 ganglia of which sometimes two are joined to a single one. (e. g. in 

 Ornithorhynchus those of the seventeenth and eighteenth thoraco- 

 lumbar nerve). Here and there I found double rami viscerales which 

 then pass through the M. psoas in a curve. 



On account of what I found in the lumbar part of the sympathetic 

 chord in other mammals I am inclined to ascribe the splicing of 

 the rami viscerales to mechanical influences, i. e. to the development 

 of the processus trans versi of the vertebrae and the M. psoas. 



A division of the rami viscerales in grey and white rami, embracing 



7* 



