NoRRlS, Nei'ves of Amphiuma. 537 



bians. The other two rootlets (Fllb {2) and VIIb{^)) enter the 

 sensory column ventral to the dorsal island. 



In the second and more ventral group of rootlets we find true 

 facialis and acusticus fibers. There may be recognized five 

 rootlets, three belonging to the auditory and two to the facial 

 nerve (figs, i, 7 and 8). Of the auditory fibers there are four 

 groups: (i) medium and large fibers that pass posteriorly into 

 the spinal VIII tract {VIII (/)); (2) medium fibers that pass 

 anteriorly in the so-called (incorrectly) "descending VIII" tract 

 (Fill (2)); (3) medium and small fibers that pass into "tract b" 

 (Necturus, Kingsbury) {FIII{j));(4.) large fibers forming a tract at 

 first distinct from (i) but posteriorly passing into the spinal VIII 

 tract or into very close proximity to it {Fill {/f)). (i) forms an 

 anterior roodet; (2) and (3) form a larger posterior rootlet; (4) 

 forms a rootlet dorsal and intermediate to the other two (figs. 

 I and 23a). Of these rootlets (i), (2) and (3) supply the sacculus, 

 lagena, macula neglecta and the posterior canal; (4) supplies the 

 utriculus and the anterior and horizontal canals. The peripheral 

 divisions of the auditory branches will not be considered here. 



The two facial rootlets consist of a dorsal one of communis 

 fibers {Fllaa) entering the brain at the anterior dorsal border of 

 (4) above mentioned, and passing into the fasciculus communis, 

 and a ventral motor rootlet {Fllab). The relative positions of 

 these rootlets of the facial and auditory nerves are subject to some 

 variation. 



h. Lateral line components of the facial nerve. — From the points 

 of entrance of its fibers into the brain the root of the lateral fine 

 portion of the seventh nerve passes anteriorly as a flattened band 

 closely compressed between the brain and the ear capsule. Most if 

 not all of the fibersof its dorsal rootlet, together with partofthe fibers 

 of the ventral rootlet, pass ventrally into the acustico-facial ganghon 

 and thence out in the main trunk of the ventral portion of the 

 seventh nerve. The fibers of the middle rootlet and part of those 

 of the ventral rootlet pass anteriorly as the "dorsal VII" into the 

 lateral line ganglion lying dorsal to and confluent with the gasse- 

 rian ganglion. Passing anteriorly from this dorsal lateralis ganglion 

 the lateral line fibers are joined by general cutaneous fibers from 

 the gasserian ganghon (the third group of fibers mentioned under 

 the head of the trigeminal nerve). These general cutaneous fibers 

 are in two distinct bands, one of which is applied to the ventral 



