6 OLOF LARSELL 



minalis is a mixed nerve, containing in some fishes peripheral 

 sympathetic fibers distributed to the blood-vessels. These ef- 

 ferent fibers make their exit in a dorsal root (N. terminalis) as 

 the viscero-motor fibers typically do in the spinal region of 

 lower vertebrates." 



Belogolowy ('12), from a study of young selachian embryos, 

 concludes that the nervus terminalis is derived from the terminal 

 portion of the neural crest. This was also claimed by Locy ('99) 

 and ('05 a). 



McKibben ('14) studied the histological structure of the gan- 

 glion terminale of Mustelus by intravitam methylene-blue stain- 

 ing. He found the great majority of the cells to be multipolar 

 and "few if any bipolar cells." Landacre ('16), from observa- 

 tions on Squalus embryos, holds that the tenninalis is combined 

 with the olfactorius as a possible general cutaneous component 

 of the latter. 



b) Ganoids. Through the studies of Brookover ('08 and '10) 

 we have very complete reports of the ierminalis for the ganoid 

 fish Amia. He concludes that the ganglion of the terminalis 

 arises from the olfactory placode a little later than do the 

 fibers of the olfactory nerve. He doubts its independence 

 and is disposed to consider it a part of the olfactor}^ system. 

 In histological observations he finds ganglion cells chiefly of sym- 

 pathetic type. He also finds fibers along the blood-vessels and 

 a connection between the terminalis fibers and the ciliary gan- 

 glion, and suggests that the circumstantial evidence leads one to 

 ascribe to it a vasomotor function, in part. The same author 

 gets similar results from Lepidosteus ('14) where the ganglion 

 terminale appears to arise from the olfactory placode after the 

 formation of the olfactory fibers. ''The disposition of the cells 

 in Lepidosteus in a more compact central and a diffuse peripheral 

 ganglion allows of its falling quite naturally into the morpho- 

 logical relations of the typical autonomic system." 



This shows the tendency toward interpreting the terminalis 

 as sympathetic in nature (or at least as containing sympathetic 

 fibers) which becomes more marked in studies of the maimiials. 



