394 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



mid in the superficial border of the medulla, and 

 finally enter the restiform body and the cerebellum 

 through the inferior cerebellar peduncle. Others 

 become superficial in the antero-lateral groove lateral 

 to the anterior pyramid, passing also to the cerebel- 

 lum, through the inferior cerebellar peduncle. 



The posterior group originate in the nuclei gracilis 

 and cuneatus and pass directly forward and up- 

 ward in the cerebellar peduncle of the same side to 

 terminate in the cerebellum. All the arcuate fibers 

 carry sensory impulses. 



The arcuate nucleus is a collection of nerve cells 

 interposed in the anterior superficial arcuate fibers at 

 a point just anterior to the pyramids of the medulla. 



SUMMARY OF TRACTS, THEIR ORIGIN AND TERMINA- 

 TIONS. 



Columns. Origin of Axones. Terminations. 



The sensory tracts are Nos. i, 2, 3, 4, 5, 6. The motor tracts are Nos. 7, 9, 10. 

 The mixed tracts are Nos. 8, n. 



THE PONS. 



The pons represents the anterior basal portion of 

 the hind-brain. It is an oval body, one inch long, 

 one inch thick, and about one and one-half inches 

 broad. It is a junctional piece between the medulla 



