572 



THE NEKVOUS SYSTEM. 



Horizontal fissure of cerebellum 

 Tuber vermis I Supra-pyramidal fissure 

 Pyramid \ N ! / Fissura secunda 



Postero-inferior 

 lobule ~ 



Parapyramidal 

 sulcus "" 



Post-tonsillar 



sulcus~ 

 Peduncle of_ 

 flocculus 



Paraflocculus 

 Flocculus 



Post-nodular fissure 



Uvula 



median bridge, which can now be called the vermis, leads to the appearance c 



a transverse depressio 

 upon the superior sui 

 face. This is the fissur 

 prima (Fig. 507, B, ( 

 and D), which become 

 the deepest and mos 



Biventral lobule COmpleX of all the mult 1 



Tonsil of tude of fissures th^ 



r cerebellum 



--Fioccuiar fissure ultimately cut into tt 

 cerebellum (Fig. 519 

 Soon afterwards the fi 

 sura secunda makes i * 

 appearance (Fig. 507,0 

 FIG. 505. INFERIOR SURFACE OF THE CEREBELLUM OF A HUMAN FCETUS and with the fissura prin 



WHICH HAS REACHED THE END OF THE FlFTH MONTH OF DEVELOPMENT. Subdivides the Verm 



into anterior, media 

 and posterior lobes. 1 



Other transverse fi 

 sures appear in rap 

 succession until tl: 

 vermis becomes cut i 

 into the following par 

 named from above (& 

 the velum medulla 

 anterius) downward 

 lingula, lobulus central 



Nodule 



Clivus monticuli 



Culmen 



| Fissura prima 



Fissura postlunaris 



Postero-superior lobule 



Supra-pyramidal fissure 



Horizontal fissure 

 Postero-inferior lobule 

 Infra-pyramidal fissure 



FIG. 506. CEREBELLUM OF A HUMAN FCETUS WHICH HAS REACHED THE END culmen declive Dvram 

 OF THE FIFTH MONTH OF DEVELOPMENT. Viewed from above and behind. ,' , 



uvula, and nodule. 



Quite unnecessary importance is usually attached to the subdivisions of the part here cal 



i/elu 



lobus ant. 

 velum med. /fiss. prima 



- fiss. postnoduk 



- nodulus 

 plx. choroid. 



B 



..-fiss. postnodul. 



nod ulus 



plx. chor.oid. 



lobus anterior 



lobulus centralis 



lingula 



fiss. praeculminata velum medullare ant.' 

 fiss. prima 



/culmen 



s lobus posterior 



V 

 riss. postnodul. 



pnma 



.-declive 



fiss. suprapyr. 



_- pyramis 

 - - fiss. secunda 

 fiss.postnodularis " uvula 



FIG. 507. MEDIAN SAGITTAL SECTIONS OF FCETAL CEREBELLA IN FOUR STAGES OF DEVELOPMENT. 

 A and B, third month ; C, fourth month ; D, fifth month. 



declive, which is described as consisting of three parts (declive, folium vermis, and tuber 



1 The term median is used advisedly because, the anterior and posterior lobes having quite insigni 

 lateral connexions, the rest of the vermis is virtually the medial continuation of (or bridge between] 

 lateral lobes. 



