276 THE RHOMBENCEPHALON. 



path (No. 3) and the indirect path (No. 4) for tactile, pain and 

 temperature impulses. It is called Cowers' s tract. 



(5) The medial (posterior) longitudinal bundle (fasciculus 

 longitudinalis medians'} (Figs. 87 and 88) runs next the median 

 plane and just under the ventricular gray matter in a position 

 similar to the one it occupies in the mid-brain (Figs. 47 and 48), 

 see page 156. It is in the pontine portion of this bundle that 

 the fibers from the oculomotor nucleus pass to the genu of the fa- 

 cial nerve, ultimately to innervate the frontalis, corrugator and or- 

 bicularis oculi ; it is in the pons, that fibers from the abducent nu- 

 cleus join this bundle, and run upward through it to the oculo- 

 motor nucleus of the opposite side and make possible the conju- 

 gate movements of the eyeballs; it is also here, that fibers, which 

 rise in the hypoglossal nucleus, leave the longitudinal bundle and 

 enter the facial nerve at the genu to be distributed by way of 

 the facial to the orbicularis oris. As in the mid-brain, the longit- 

 udinal bundle includes the two functional tracts, the descending 

 strand and the ascending strand. 



(6) Anterior Longitudinal Bundle. This ocular-reflex bundle 

 is continued from the mid-brain down through the pons in nearly 

 the same relative position. Diverging a little from the medial 

 longitudinal bundle as it descends through the pons, it is located 

 in the formatio reticularis a short distance ventro-lateral from it. 

 The anterior longitudinal bundle can be recognized in normal 

 adult tissue only in the dorsal tegmental decussation (Meynerti) 

 of the mid-brain: lower down it can be distinguished from the 

 surrounding tissues by degeneration and medullation but in no 

 other way (Fig. 87). Having given fibers to the oculomotor and 

 trochlear nuclei above, it sends fibers to the nucleus of the abdu- 

 cent nerve at this level, and perhaps to other pontine nuclei (see 

 Mid-brain, page 158). 



(7) Rubro-spinal Tract. In the mid-brain, we have traced 

 this tract from the red nucleus, through the ventral tegmental 

 decussation (Foreli), to the opposite side, where it mingles with 

 the lateral fillet down near the isthmus (Figs. 47 and 48). It 

 occupies the same position in the upper half of the pons; it is close 

 to the posterior surface of the corpus trapezoideum in the lower 



