296 THE RHOMBENCEPHALON. 



(Figs. 92 and 94). Situated between the inferior olivary nuclei, 

 it is on that account so named. Superiorly, it is continued as the 

 medial fillet. The medial fillet rises from the nucleus funiculi 

 gracilis and nucleus funiculi cuneati of the medulla and crosses 

 through the median raphe in the fillet decussation. As the fillet 

 runs brain-ward, it receives fibers from the terminal nuclei of 

 common sensory cerebral nerves and from the vestibular nuclei. 

 Along its lateral border, it is accompanied for a short distance 

 in the pons by the lateral fillet. The medial fillet is composed 

 of ascending axones which constitute a "cerebral" tract for the 

 sensory fibers of spinal and cerebral nerves. It carries ordinary 

 sensations (tactile and muscular) to the superior quadrigeminal 

 colliculus by the superior fillet, and to the thalamus by the greater 

 part of the medial fillet. 



The medial longitudinal bundle (fasciculus longiiudinalis 

 mediates) (Figs. 92 and 95) which we have studied in the mid- 

 brain and pons, constitutes a very distinct strand in the superior 

 half of the medulla ; but below the level of the olive it can be identi- 

 fied in the anterior fasciculus proprius only by a study of its 

 medullation or of its degeneration. It is continuous with the 

 anterior fasciculus proprius of the spinal cord. Its location is 

 next the median raphe and the ventricular gray substance, imme- 

 diately anterior to the hypoglossal nucleus, in the upper medulla. 

 The same position is occupied by it in the mid-brain and pons. 

 It is here in the medulla that the hypoglossal fibers are supposed 

 to enter it and run up to the colliculus facialis, where they join 

 the facial nerve at the internal genu. At the middle of the medulla 

 the decussation of the fillet pushes this bundle forward and some- 

 what away from the median plane, so that it runs between the 

 fillet decussation and the medial accessory olivary nucleus. Below 

 the level of the fillet decussation it runs between the decussatio 

 pyramidum and the isolated head of the anterior columna of gray 

 substance. Rising primarily in the gray matter of the cord, the 

 ascending part of the medial longitudinal bundle is augmented 

 in the medulla and pons by fibers from the terminal nuclei of sen- 

 sory cerebral nerves. Most of its ascending fibers cross the 

 median line and terminate in the motor cerebral nuclei on the 



