890 



THE NERVE SYSTEM 



older anatomists the nidus avis or "bird's nest" [Ileil and Vicq d'Azyr].) The 

 junction of uvula and tonsilla is an attenuated isthmus marked by a few shallow 

 furrows and termed the furrowed band. 



The nodular lobe comprises the nodulus (iwAulus vermis} (in the inferior vermis) 

 and the flocculus (flocculi secondarii) of each side, connected by a delicate lamina 

 of white substance, the velum medullare posterius. Each flocculus lies adjacent to 

 the ventrolateral surface of the peduncular mass, extending into the ventral ex- 

 tremity of the peduncular fissure. The flocculi of the two sides are connected 

 with each other by a band of white substance, termed the posterior medullary velum 

 in its medial portion, while its lateral expansions toward the flocculi are termed 

 the peduncles of the flocculli. 



FIG. 655. Diagram showing the origin and course of the fibres of the peduncles of the cerebellum. 



(Edinger.) 



The Internal Structure of the Cerebellum. In any section of the cerebellum we 

 may recognize the interior white substance, corpus medullare (medullary body), and 

 the peripheral gray cortex. The white substance in each lateral hemisphere is 

 more bulky than in the median vermis, while the cortex is of more uniform thick- 

 ness throughout. In a sagittal section in the mesal plane the central white core 

 is seen to divide into two main branches anterior ramus or preramus and posterior 

 ramus or postramus; these main branches divide and subdivide into a series of 



