THE SYMPATHETIC NERVOUS SYSTEM. 219 



side. Of the various modes of origin of this nerve among 

 the bony fishes enumerated by Stannius (p. 138) the 

 arrangement here conforms most closely to that of Belone. 

 The commissural nerve as figured (ij. c.) is the left root 

 of the splanchnic nerve. 



The "head part" of the sympathetic trunk may be 

 regarded as beginning from the same ganglion {sy. 7), 

 which gives rise to the root of the coeliac ganglion (Stan- 

 nius' usage). It runs cephalad, as before, along the dorsal 

 surface of the head kidney, and under the ganglion of the 

 first spinal nerve there is found the last ganglion of the 

 "head part," the sixth from in front {sy. 6), not counting 

 the ciliary ganglion. This ganglion is much larger than 

 any of the preceding. It lies close under the ganglion of 

 the r. lateralis vagi and may send some fibres into it. In 

 front it fuses broadly with the caudal part of the vagus 

 ganglion, being particularly intimately united with that 

 portion which I have termed the jugular ganglion. As in 

 the preceding cases, some of the fibres pass through the 

 ganglion without losing their medullary sheaths. 



The sympathetic trunk now separates from the vagus 

 ganglionic complex slightly and runs along its inner and 

 ventral aspect between it and the lower outer edge of the 

 vagus foramen. Just cephalad of the closure of that fora- 

 men ganglionic cells reappear in the trunk. This small 

 ganglion {sj-j) lies between the vagus ganglion and the 

 emerging root of the glossopharyngeus, but does not com- 

 municate with either. The trunk now fuses with the IX 

 root in which it can be separately followed to the IX gan- 

 glion. Just before reaching the latter it withdraws from 

 the IX root, but follows along its dorsal surface as a sepa- 

 rate round bundle and here there is another minute 

 sympathetic ganglion {sy. 4). 



