98 Journal of Comparative Neurology, 



postvermis and their lateral prolongations. For the extent and 

 relative mass of these in man consult Figs. 64, 66 and 67, and 

 in the cat Figs. 20, 23 and 44. 



Simunary. 



The following points are believed to be new or little 

 known. 



1. Some ideas about the epencephal as a definitive brain 

 segment. 



2. The mammalian cerebellum is developed from the cau- 

 dal part of the epicoelian roof. 



3. The definition of the cerebellum as "that part of the 

 epicoelian roof which is clothed v/ith ectocinerea. " 



4. The existence of paired notches in the caudal part of 

 the epicoelian roof. See Fig. 6. 



5 An explanation of the shifting of the ripa ventrad. 



6. The non-appearance of the cerebellum on a mesal sec- 

 tion of the early embryo brain. 



7. That the lateral parts are formed first, although, as 

 stated by previous observers, they do not receive their adult 

 foliation till after the mesal sulci have appeared. 



8. That mesal sulci appear before the vermis, as a dis- 

 tinct lobe, is formed. 



g. The late appearance of the vermis. 



10. A new topographic terminology for the cerebellum. 



11. The recognition of new sulci : 



a. The floccular sulci, paired at first, but fused at 

 the meson later. 



b. The parafloccular sulci, paired, but not fusing. 



c. The interfloccular sulci, paired, but not fusing. 



d. The interpilear sulci, paired, but not fusing. 

 These are best seen in the embryo. 



1 2. The first sulci appear on the lateral parts, not on the 

 vermis, as has been previously stated. 



13. The existence of the interpileum marking the mesal 

 limit of the interpilear sulcus. 



