580 



frem the inner part of the posterior pyramid, the outer side of the 

 latter undergoes a remarkable change of structure, and becomes the 

 chief origin of the anterior division of the auditory nerve, which in 

 its course outwards runs between the restiform body and the gelati- 

 nous substance or posterior cornu. The posterior division of the 

 nerve winds transversely inwards over the restiform body to reach 

 the auditory ganglion. 



Intimately connected with the auditory nerves and ganglia is the 

 structure which, in animals, is called the trapezium, and which the 

 author has found to enclose a remarkable vesicular sac resembling 

 that of the olivary bodies. The analogue of the trapezium exists in 

 the human medulla. 



The facial nerve, or portio dura of the seventh, after passing 

 through the trapezium, proceeds transversely inwards to the fasci- 

 culus teres, which contains a mass or column of stellate cells, and 

 through which it spreads, exchanging fibres or forming a loop with 

 the sixth or abducens nerve, which arises from the same nucleus. 

 The glossopharyngeal nerve has more than one origin. It passes 

 out in several bundles through the gelatinous substance or posterior 

 cornu, in which it forms a plexus with longitudinal fasciculi of 

 fibres which may be traced upwards to the larger root of the fifth 

 nerve. 



The connecting fibres between the anterior and posterior portions 

 of the medulla are very numerous and complicated. For convenience 

 of description, they may be divided into two parts, superficial 

 and deep. The superficial are the superior layers of the arciform 

 system, and arise from the restiform body and its ganglion : the 

 deep fibres, more or less blended with the first, arise from the 

 remains of the post-pyramidal and the restiform ganglia. Together 

 they form a complicated network, or plexus, interspersed with innu- 

 merable and variously shaped cells, which frequently communicate 

 around the longitudinal bundles of the lateral columns, through 

 which and the olivary body the fibres of the plexus proceed forwards 

 and inwards to the raphe, where they decussate with those of the 

 opposite side, and become continuous with the arciform fibres which 

 were traced to the raphe round the anterior pyramids as the super- 

 ficial set. The raphe, therefore, is the seat of a very complicated 



