102 CHARLES BROOKOVER 



In fig. 33 there is a transverse fiber that runs across the 

 stalk of the epiphysis at a higher level than the longitudinal 

 fibers and appears to leave the confines of the pineal stalk. This 

 seems to provide for connection with the nerves already de- 

 scribed among the tubes of the paraphysis. Also, in a number of 

 Golgi impregnations the fibers of the nerves of the meninges 

 reach the basement membrane of the pineal stalk (fig. 29), 

 if indeed, they do not pass into it. This provides a nervous 

 mechanism capable of correlating the blood supply or the fluid 

 secretions of the paraphysis and the pineal stalk. 



In the diagram of the intra-cranial course of the sympathetic 

 system of Amia (fig. 25), I have connected the fibers from the 

 profundus nerve with the pineal stalk on the above evidence. 

 The pineal structures of vertebrates are generally considered 

 atavistic remnants of a former eye. If such an eye had a sympa- 

 thetic component, the nerve supply to its stalk in Amia might 

 perhaps be considered as remaining after sight degenerated. 

 Or there might have been a complete change of function resulting 

 in the present nervous structure of the pineal stalk. However 

 that may be, it can be seen (fig. 25) that there is provision for 

 a longitudinal connection between the supposed ancient nerve, 

 the hypothetical thalamic, and the post-optic sympathetic system. 

 It should be explained in this connection that point "b" is anterior 

 to point a (fig. 25) in young specimens of Amia so that the sym- 

 pathetic chain runs forward instead of bending posteriorly. The 

 brain is carried farther caudad in its cavity as the fish comes to 

 maturity. The above described sympathetic chain furnishes 

 connections with the posterior part of the sympathetic system for 

 two of the three supposed neuromeres which Johnston ('05) and 

 others have assigned to the forebrain. The last link in the for- 

 ward extension of the sympathetic chain is probably represented 

 in the connection of the intra-cranial sympathetic just described 

 with the nervous terminalis, now to be considered more fully than 

 before. 



In discussing the central connections of the nervus terminalis 

 I have pointed out the fact that non-medullated fibers were found 

 along the arteries ventral of the olfactory bulbs and that this 



