Kingsbury, Brain of Necturus. 187 



asserted to contain motor elements (Strong '95), in which case 

 we should expect to find another origin for a portion of the 

 fibers. 



W\aa, is small and arises at the level of the eighth nerve 

 and dorsad of it, from \he fasciculus communis and a small ac- 

 cessory bundle of fibers which springs from the cinerea meso- 

 dorsad of the fasciculus communis. The fibers are small and 

 lightly meduUated, On their way to the periphery they pene- 

 trate tract b, which is well developed at this level. The gang- 

 lion of this contingent is fused with that of the eighth, and rep- 

 resents probably the geniculate ganglion, the nerve itself repre- 

 senting the/«;'^ intermedia (Strong). Strong finds that the pal- 

 atine nerve is formed by this component of the seventh. In 

 Necturus, as indeed in other urodeles, this nerve (palatine) does 

 not, as in the Anura, come into relation with the Gasserian 

 ganglion. 



Dorsal F//.— This is the VII u and 1, of Osborn ; Vllb 

 or Dorsal VII of Strong. The fibers of which it is composed 

 differ greatly in appearance from the other fibers of the facial, 

 and indeed the other cranial nerves except IX^+^ with which 

 they correspond exactly. The figures show them very inade- 

 quately ; they are large and with dense myelinic sheaths. In 

 Necturus the roots unite to form the dorsal seventh, and they 

 are here spoken of as Vllb^ and Vllb^, VIP rising dorsad and 

 slightly caudad from a region well demarcated ffom it. At 

 about one-third of the distance (going cephalad) between IX^ 

 and VIII there begins to be formed in the extreme dorsal por- 

 tion of the dorsal tracts an area of amyelinic substance of a 

 structureless appearance — ground substance. This increases in 

 amount to the region of the eighth nerve and decreases again 

 cephalad of this point, disappearing entirely half a millimeter 

 cephalad of that nerve. Into this island resting upon tract «, 

 Vllb' enters at the level of the eighth. The fibers lose their 

 myelin immediately on their entrance and disappear, turning 

 neither cephalad or caudad. The cells immediately adjoining 

 this area undoubtedly represent the terminal nidus of this root, 



Vllb^ enters the same portion of the dorsal tracts as does 



