Kappers, Teleosteati and Selachian Brain. 83 



of the lateralis center. Johnston states positively, "The lobus 

 lineae lateralis is shown by its structure to be an integral part of the 

 acusticum," and "the central relations of the lateral line and 

 VIII nerves add support to the hypothesis that the ear is derived 

 from canal organs." In his work on Chimaera monstrosa Cole 

 says, "doubtless all the lateral line nerves arose primitively by a 

 single root from the tuberculum acusticum," and in his descrip- 

 tion of the Gadidee, "There can be little doubt that the primitive 

 lateral line organs gave rise both to the recent lateral line system 

 and also to the vertebrate auditory organ"; and C. J. Herrick 

 also considers the organs which end in the acustico-lateral center 

 as "kindred structures." 



The radix anterior and posterior of the so-called nervus lateralis 

 must be considered as the foremost and hindmost roots of the 

 static system, of which I shall now briefly describe the only root 

 which has remained in man — the nervus octavus. 



This nerve, of which in fishes only the vestibularis is clearly 

 visible, enters into its terminal region under the radix anterior 

 lateralis. A small number of its large medullated fibers end at 

 the place of entrance into the octavus nucleus, composed of large 

 cells placed ventrally. A larger part end more dorsally in the 

 chief nucleus, composed of small cells. The greater part of the 

 vestibularis fibers, however, take a longitudinal course in the 

 oblongata, part forward to reach the cerebellum, as described by 

 C. J. Herrick, Edinger and Johnston, but a larger part back- 

 ward as far as the most posterior region of the tuberculum acus- 

 tico-laterale, which is always covered by the cerebellar crest. 

 Here the tr. descendens N. VIII (according to C. J. Herrick's 

 statement containing a great many secondary eighth fibers) 

 gradually goes along the side of the oblongata higher up, ending 

 at the same level as the descending fibers of the lateral system. 



As stated above, I cannot confirm for the teleosts Johnston's 

 observation on Acipenser that fibers of the octavus end along with 

 the descending quintus root in the nucleus Rolandi, although the 

 terminal regions of these lie quite near to each other and both 

 are evidently the continuation of the cornu posterior of the 

 spinal cord. I could nowhere find a decussation of acusticus 

 fibers in the oblongata. Yet, as mentioned in the description 

 of the external form of the oblongata, the tubercula join 

 and at their frontal end and especially their caudal end are 



