GRAY MATTER OF THE PONS. 279 



superior) is situated in the lateral part of the formatio retic- 

 ularis in the dorsal portion of the corpus trapezoideum (Fig. 88). 

 It lies just ventral to the nucleus of the facial nerve and ventro- 

 lateral to the olivary bundle of fibers. The nucleus contains small 

 bodied nerve cells; and, in this respect, resembles the olive of the 

 medulla. Its outline is crescentic, convex toward the median 

 line. In size it is microscopic. According to Bruce and Cun- 

 ningham it is continuous with the nucleus of the lateral fillet. 

 The superior olive constitutes a subordinate relay in the auditory 

 path, receiving fibers from the cochlear nuclei of both sides and 

 contributing fibers to both lateral fillets (Fig. 89). 



The superior olivary nucleus gives off a small strand of fibers, 

 called the olivary pedicle, which runs dorso-medially, between the 

 recurrent and emergent parts of the root of the facial nerve, to 

 the nucleus of the abducent nerve; there some of its fibers end, 

 the remainder join the medial longitudinal bundle and run to the 

 trochlear and oculomotor nuclei. The pedicle forms part of an 

 auditory-ocular reflex arc. 



A small accessory nucleus, called the nucleus prceolivaris, is 

 situated just a little ventral to the superior olivary nucleus; and a 

 second one embraces the convexity of the nucleus olivaris superior, 

 lying on the medial side of it. The latter is the nucleus semi- 

 lunar is. 



Nucleus of the Trapezoid Body (N. Corporis Trapezoldei}. 

 This nucleus is deeply imbedded in the trapezoid body ventro- 

 medial to the superior olivary nucleus (Fig. 88). Its cell-bodies 

 are scattered and, like the other nuclei of the olivary group, it 

 forms a partial relay for the auditory path. This nucleus is pecu- 

 liar; the fibers it receives terminate in the form of cup-shaped discs, 

 acustic cups, which are in direct contact with its cell-bodies (Held). 



(2) The nuclei of the reticular formation contained in the 

 pons are the n. centralis superior, n. centralis medius, n. centralis 

 inferior and n.. later alls medius. All are microscopic. They are 

 made up of large scattered cell-bodies whose axones, dividing T- 

 like, are both ascending and descending in direction (Tschermak). 

 We may divide these axones into two groups, a crossed and an 

 uncrossed. The crossed fibers pierce the median plane and become 



