596 'Journal of Comparative Neurology and Psychology. 



upon which they He is cut transversely the fibers are seen to pierce 

 the muscle and lie directly on the wall of a vessel or sinus. Trans- 

 verse sections through the very region shown in fig. 22 show this 

 very clearly. It is not so easy to prove whether these fibers mayor 

 may not be related to the lining of the gill sac or the epithehum 

 of the gill filaments. The fibers which supply the greatc?r part 

 if not the whole of the lining of the gill sacs, enter the sacs on their 



Fig. 22. The proximal portion of the sympathetic trunk of the right side, just behind the auditory 

 capsule and over the first gill sac, in a horizontal section. Magnification, 90 diameters. 



anterior and posterior surfaces as above described and spread 

 over the whole wall. The fibers of the sympathetic trunks arrive 

 upon the walls of the gill sacs dorsally and ventrally, but here in 

 many cases at least they mingle with the network of interlacing 

 fibers from the former source and it is no longer possible to dis- 

 tinguish them with certainty. By direct observation the possibility 

 can not be excluded that fibers from what are here called sym- 



