NERVUS TERMINALIS TN AMIA 99 



trolled by nerves. However, Putter ('03) states that it has not 

 been proven that ciliary action is under the control of the nervous 

 system except perhaps in a few molluscs and annelids. 



The pineal stalk of Amia has an innervation that shows some 

 characteristics of sympathetic nerves. Cajal preparations show 

 that there are more than fifty nerve fibers joining the brain from 

 the pineal stalk. Some of these fibers pass to the habenula>, 

 but a larger number turn caudad to the region of a gland-like 

 structure beneath the superior commissure. Johnston ('01, p. 

 108) has called this structure in Acipenser the epiphysial sac and 

 shows that nerve fibers end among its cells but he tells me these 

 fibers do not come from the epiphysis. It is prominent in many 

 preparations of Amia since it stains deeply with methylen blue 



pineal stalk 

 ciliated epithelium /•'"" ) 



Fig. 29. From the same preparation as fig. 27, showing the relation of nerves of 

 the meninges to the pineal stalk. X 64. 



and with hematoxylin. Most of the nerve fibers from the pineal 

 stalk are soon lost in all of my preparations near the walls of the 

 third ventricle, after passing the glandular epiphysial sac. 



In a fortunate Golgi preparation of a young Amia about 12 mm. 

 long I was able to show the details of a neurone of the pineal 

 stalk (fig. 31), in a single section. This neurone has its cell 

 body in a position near the distal end of the stalk. Its dendrites 

 branch near the surface of the stalk, while its axone passes cen- 

 trally to be lost between the habenula and the superior commis- 

 sure. At this time the pineal stalk comes into contact with the 

 ectoderm and I have often noticed in very young specimens of 

 about this same size that there is a light spot in the skin free of 



