NERVUS TERMINALIS IN AMIA 95 



on the right side of the specimen. As the cells are very much like 

 those of the profundus nerve outside the cranial cavity, it was at 

 first inferred that they migrate into the cranial cavity along the 

 fibers from the profundus nerve. This seemed all the more prob- 

 able because the cells inside the cranial cavity were not found 

 in sections of young specimens, but the number of cells is very 

 small in the adult and might be overlooked very easily in the 

 young among so many blood vessels. There is an interesting 

 observation to be mentioned here as having a possible bearing 

 on the origin of the posterior group of cells within the cranial 

 cavity. This group lies not far from the position of the evanescent 

 thalamic nerve described by Miss Piatt ('91) in Acanthias. In 

 fact, in one Cajal preparation of adult Amia, it was thought that 

 a few fibers of the thalamic nerve were found entering the brain 

 laterally anterior to the habenular bodies. For some reason there 

 was a break in the continuity of the fibers at the brain wall. Inside 

 the brain, fibers were seen running from this point. As no evi- 

 dence of a nerve in this location has been found in any other 

 specimen the presence of a thalamic nerve in Amia is in doubt. 



When the nerve cells at this point (b in fig. 25) are examined in 

 surface views of total mounts, they are found to be well scattered. 

 Fig. 26 shows five cells in their natural relation to one another 

 in the most crowded portion of the ganglion of nearly twenty 

 cells. Some of these cells are closely applied to the membranous 

 pallial wall of the forebrain. In Cajal preparations I have found 

 one or two nerve cells lying near the median line among the para- 

 physis tubes situated between the dorsal sac and the pallium of the 

 forebrain. Fibers were often found here among the paraphysis 

 tubes establishing what may be considered as a commissure 

 between the two halves of the intra-cranial sympathetic system. 



As already mentioned, Golgi impregnations show that the blood 

 vessels everywhere within the cranial cavity have nerve fibers 

 branching on their walls, but it is not so easy to determine whether 

 the paraphysis and the ciliated epithelium of the dorsal and dien- 

 cephalic sacs have their intrinsic nerves or not. The paraphysis 

 is a glandular structure with tubes gathering to a duct which 

 pours its secretion into the brain ventricle just beneath the middle 



