NERVUS TERMINALIS: MAMMALS 7 



c) Teleosis. The presence of the nervus terminalis in bony 

 fishes was first reported by Sheldon and Brookover ('09) in the 

 carp (Cyprinus carpio). Sheldon ('09) independently takes up 

 the central course of the nerve. The tract is composed of un- 

 myelinated fibers. Numerous scattered ganglion cells were 

 found on the ventromedial aspect of the olfactory nerve, from 

 some of which coarse fibers were traced to the olfactory epithel- 

 ium where they were distributed with the olfactory nerve fibers. 

 Centrally the fibers for the most part decussate at the anterior 

 commissure, but no exact nuclear connection could be found. 



Brookover and Jackson ('11) studied the development of the 

 terminalis in Ameiurus, and also its adult relations by means of 

 the silver-impregnation methods. They find the nerve to be 

 closely related in its development to the olfactory nerve and 

 are inclined to consider it a part of this rather than as an inde- 

 pendent nerve. They point out the proximity of fibers of the 

 nervus terminalis to blood-yessels, but find only a single in- 

 stance where the blood-vessel definitely appeared to be inner- 

 vated by terminalis fibers. A vasomotor functon is suggested. 



Amphibia. C. Judson Herrick ('09) found in larval and adult 

 frogs a bundle of unmyelinated fibers corresponding so. closely 

 to the nervus terminalis of the fishes in its central course that he 

 considered it to be homologous with the latter. He was unable 

 from his material to determine peripheral terminations. The 

 nerve is not exposed as in selachians. It runs along the ventral 

 border of the olfactory nerve and becomes imbedded in the brain 

 substance just caudad to the glomerular formation. Within the 

 brain substance it passes caudally (in one case showing arboriza- 

 tions in the lamina terminalis) and the fibers cross in the middle 

 part of the anterior commissure. 



McKibben ('11) traces the course of the nervus terminalis in 

 Necturus and a number of .other tailed amphibians. As in the 

 frog, it is mainly imbedded in the brain substance. The principal 

 central distribution is to the preoptic nucleus. The central 

 bundle undergoes a partial decussation in the anterior commis- 

 sure, but groups of direct fibers extend further backward from 

 this point, giving off branches at intervals. The continuity of 



