SURFACES. 



159 



cord. In function the anterior longitudinal bundle is reflex; 

 it is connected with all ocular reflexes which are excited by impulses 

 from the retinae, such as, accommodation for distance, pupillary 

 contraction and dilatation. 



The Fillet or Lemniscus (Figs. 46, 47 and 48). Near the 

 upper end of the pons, in the ventral part of the formatio reticu- 

 laris, the fillet, or lemniscus, forms "a very broad band of fibers 



Fig. 47. Section of the mid-brain through superior colliculi and the apparent 

 origin of the oculomotor nerve. (Original.) 



a. Sulcus laternlis of mid-brain, b. Red nucleus, c. Medial longitudinal bundle, d. Oculo- 

 motor nucleus, e. Stratum griseum centrale. f. Colliculus superior of corpora quadrigemina. 

 g. Formatio reticularis. h. Medial fillet, i. Medial geniculate body. j. Optic tract, k. Basis 

 pedunculi. 1. Dorsal tegmental decussation (Meynerti). m. Ventral tegmental decussation 

 (Foreli). n. Fossa interpeduncularis. o. Substantia nigra. p. Fronto-pontal tract, q. ad. N. 

 r. Pyramidal tract, s. Intermediate tract, t. Temporo-pontal tract. 



on either side of the median raphe. The fillet is equal in width 

 to half the transverse diameter of the mid-brain. It continues 

 into the ventral portion of the tegmentum, but immediately divides 

 into two fasciculi, viz., the medial fillet, and the lateral fillet. 

 Farther forward a small bundle leaves the lateral part of the 

 medial fillet and runs up to the superior quadrigeminal colliculus. 

 That bundle is called the superior fillet. 



