1 82 Journal of Comparative Neurology. 



direct relation of acustic fibers (of the vestibular nerve) to the 

 cerebellum, is stated by Edinger, ('86) Sala and Brandis, but 

 disputed by Kolliker. An ascending root of the eighth nerve 

 is recognized by Goronowitsch, and by Stieda in the Axolotl. 



In addition to the fibers spoken of above, others seem to 

 end almost immediately on entering the brain, in close proxim- 

 ity to large cells situated in the lateral region, which have been 

 likened to the large cells in Petro^nyzon connected with the me- 

 dian crossed and lateral uncrossed Mullerian fibers. Similar 

 cells occur caudad as far as IX^ and may possibly represent, or 

 be closely connected with the terminal nidus for the ascending 

 acustic fibers. Osborn suggests a comparison of these with 

 Deiter's nidus of mammals. But a single acustic root was ob- 

 served in Necturus. This is contrary to certain theories of the 

 development of the ear and with results in some other, especial- 

 ly higher forms ; it agrees however with the condition found in 

 Cryptobranchiis and the Axolotl (Steida '75). Possibly the two 

 roots may be represented by the ascending and descending 

 fibers. The eighth is VHP of Osborn in CryptobrmicJms. The 

 correspondence between the two forms would seem to be close, 

 though his figures leave much to be desired. The relation to 

 the large cells is noted by him, and ascending and descending 

 fibers, though the ascending tract apparently does not have as 

 great extent as in Necturus. The derivation of the descending 

 fibers from the mesencephal after decussation in the cerebellum, 

 must seem doubtful from the relations found elsewhere. 



Facial Nerve. — This nerve is formed of two components, 

 VIIa:«, a sensory root from thQ fasciculus communis of Osborn, 

 and YWab, motor, formed by two, or in some cases three, 

 rootlets, arising from the oblongata ventrad of and at about the 

 same transverse plane as the eighth. 



VII^^^". — At about the exit of the tenth (X^) nerve, myel- 

 inic fibers begin to appear in the cinerea dorsad of a nidus of 

 large cells in the ventro -lateral portion of the floor. From here 

 to slightly cephalad of IX\ fibers spring continuously from this 

 region and unite to form a close bundle which passes mesad to 

 lie dorsad of the posterior longitudinal bundle and immediately 



