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HUMAN PHYSIOLOGY 



the anterior corpora quadrigemina, and a mesial fillet, which 

 passes on to the optic thalamus, and there ends by forming 

 synapses. 



2. The direct cerebellar tract passes up into the restiform 

 body, and so on to the superior vermis of the cerebellum. Its 

 fibres form synapses round cells chiefly on the opposite side. 



3. The ascending antero-lateral tract passes up beside 

 the last, but it leaves it in the restiform, and courses forward, 

 to arch back into the cerebellum round the superior cere- 



FIG. 83. Cross Section through Medulla Oblongata above the decussation of the 

 Pyramids. P.M. and, P.L., Postero-median and Postero-lateral tracts of the 

 Cord ; N.G. and N.C., Nucleus Gracilis and Cuneatus. giving off the Fillet 

 Fibres crossing at F. ; V., Ascending Root of Fifth Nerve; G. t Nucleus of 

 Glossopharyngeal Nerve ; A.H., Anterior Horn of Spinal Cord ; P., The 

 Anterior Pyramids; Z>.(7., Direct Cerebellar Tract; A. and D. Ant. L., 

 Ascending and Descending Antero-lateral Tracts. (After BRUCE.) 



bellar peduncle and to form synapses with the cells of the 

 superior vermis. 



B. Outgoing. 1. The fibres from the cerebral cortex, 

 which form in the cord the crossed and direct pyramidal 

 tracts, pass down in the middle part of the crusta (Fig. 

 90, P.) of the crura cerebri, and coursing between the super- 

 ficial and deep transverse fibres of the pons (Fig. 86, P.), 

 come to lie in the anterior pyramids of the medulla (Fig. 

 83, P.). At the lower end of the medulla most of these 

 fibres cross over to the lateral column of the cord; some, 



