1 88 STRONG. [Vol. X. 



{B and C), which belong more especially, apparently, to the 

 fasciculus communis component, would correspond to the two 

 outer ganglia on the IX and X in the higher vertebrates, 

 namely, those usually designated the ganglion petrosum IX 

 and ganglion trunci vagi. They would be partially, at least, 

 homodynamous with the ganglion geniculi. 



[c) Comparison with the Fishes. — It is evident that so 

 important a tract as the fasciculus communis must be rep- 

 resented among the forms below Amphibia, and it is tolerably 

 certain that the homologue is the lobus vagi of fishes. 



In Goronowitsch's article on the brain and cranial nerves of 

 Acipenser (22,) is the following: "In der Gegend des Calamus 

 scriptorius ist, wie gesagt, die graue Substanz des Hinterhornes 

 breiter entfaltet. Sie hat dieselbe Struktur wie im Riacken- 

 mark. Medial vom Hinterhorne erscheint allmahlich eine neue 

 Lage von grauer Substanz. Sie besteht aus feinkornigem 

 Grundgewebe, in welchem viele kleine Nervenzellen eingebettet 

 liegen (Fig. 45 L v.). Zwischen diesen Zellen verlaufen die 

 feinsten Fasern in verschiedenen Richtungen. In proximalen 

 Abschnitten wachst die Querschnittsoberflache dieser Sub- 

 stanz. Sie verbreitet sich in dorsaler Richtung und verdrangt 

 lateral den Hinterhornkopf. In proximalen Ebenen bildet 

 diese graue Substanzlage einen Vorsprung im ventriculus IV. 

 Es ist das der Lobus vagi." Goronowitsch mentions, as do 

 other writers, the series of swellings visible in the wall of the 

 ventricle, and caused by the lobus vagi, and says they corre- 

 spond to the bundles making their exit from it. They form the 

 dorsal source of the Vagus and Glossopharyngeus roots, exclu- 

 sive of the N. lateralis, and are fine-fibred. Goronowitsch also 

 finds that a bundle is given off from the lobus vagi to the 

 Facialis. 



In all accounts there is a remarkable agreement, — the situa- 

 tion in which it appears, in the vicinity of the opening of the 

 fourth ventricle, its peculiar appearance and composition 

 there which leads to its description as " eine lichte Stelle," 

 "ein rundlicher Fleck," "eine runde Gewebsinsel," "ein Langs- 

 biindel feiner Fasern eingelagert in einer dichten grauen 

 Masse," "eine neue Lage von grauer Substanz," consisting of 



