304 HUMAN ANATOMY. 



The inferior peduncles., or restiform bodies, connect the 

 medulla and cord with the cerebellum. 



The superior peduncles connect the cerebellum with the 

 cerebral cortex. After decussating some of the fibres pass to the 

 red nucleus in the tegmentum of the crura cerebri; others pass 

 through the optic thalamus to end in the Eolandic region, and 

 some end in the optic thalamus. 



The cerebellar cortex consists of two layers : an outer, 

 molecular layer, and an inner, granular layer. Between these 

 two layers is a single layer of large cells, the cells of Purkinje. 



THE STRUCTURE OF THE MIDBRAIN. 



The midbrain consists of a dorsal part, the corpora quad- 

 rigemina, and a ventral part, the crura cerebri. 



It is tunneled by the aqueduct of Sylvius, which connects 

 the fourth ventricle with the third ventricle. 



The upper end of the crura cerebrisis encircled by the optic 

 tract. 



On section the crura cerebri show a ventral and lateral 

 portion, the tegmentum, and a dorsal portion, the lamina 

 quadrigemina. The ventral portion contains the substantia 

 nigra. The fissure of Sylvius is surrounded by gray matter, 

 from which the third, fourth, and a portion of the fifth cranial 

 nerves take origin. 



The inferior quadrigeminal bodies receive the fibres of the 

 lateral fillet. 



The superior quadrigeminal bodies consist of four strata: 

 stratum zonale, stratum cinereum, stratum opticum, and stratum 

 lemnisci. The mesial fillet in part ends in the latter. 



The lateral fillet also gives a few fibres. 



Some fibres from the occipital lobe and fibres from the 

 retina, conveyed by the superior brachium, end in the superior 

 quadrigeminal bodies. 



The superior cerebellar peduncles have been described ; they 

 connect the cerebellum with the cerebral cortex. 



The red nucleus is found in the tegmentum. Some of the 

 fibres of the superior cerebellar peduncles end there. 



The posterior longitudinal bundle lies in the tegmentum and 

 is the continuation upward of the tract of the same name in 

 the medulla and pons. It is connected with the nuclei of the 

 motor nerves of the muscles of the eyeball. 



The lateral fillet is continued upward from the pons in the 

 tegmentum. Its connections with the superior olivary nuclei 

 and the nuclei of the eighth nerve have been described. 



