NERVUS TERMINALIS IN AMIA 55 



ing there are three points of correspondence : (a) same structure, 



(b) same peripheral ending in the nasal mucous membrane, and 



(c) same termination in the prosencephalon. He thinks we can- 

 not say anything definite as to its function at present. John- 

 ston ('06, p. 106) suggests that it is probably a general cutaneous 

 nerve. Allis ('97) noted that the ganglion in Amia develops at 

 the same time as the ciliary ganglion and suggested that, since 

 its cells resemble those of the sympathetic rather than cerebro- 

 spinal ganglia, the nerve is probably a sympathetic nerve. 



Allis ('97) described each olfactory nerve of Amia as being 

 made up of three bundles, of which the smaller, ventro-median, 

 constitutes the nerve "n" of Pinkus. He states that there is an 

 interchange of fibers between all three of the bundles in the young 

 as well as in the adult. He says, 



In the adult the ventro-median bundle of the olfactorius is distributed, 

 so far as macroscopic observations can show, to the nasal epithelium at 

 the extreme anterior end of the nose. In embryos such is also its 

 apparent distribution, though I have never been able in my preparations 

 to trace it definitely to that tissue. During the larger part of its course, 

 in 30 mm. to 50 mm. specimens, it is easily distinguished from the lateral 

 bundles by the presence of the large round cells which Pinkus describes 

 in Protopterus. Near the anterior end of the olfactorius, however, these 

 cells disappear, and the fibers into which the bundle breaks up cannot 

 be distinguished from the other terminal branches of the main nerve. 



He continues by saying that centrally, 



The fibers of this bundle enter, in large part, with the fibers of the lateral 

 bundles into the anterior end of the lobus. 



A few of its fibers were traced by him in one series of sections 

 caudally ventral of the brain membranes to enter the brain 

 lateral to the recessus interolfactorius, which latter term he 

 explains by saying, 



in Amia, in front of the lamina terminalis, or sulcus olfactorius, and 

 hence into the lobus olfactorius and not into the forebrain proper 



(p. 512). 



