SUPERIOR SURFACE OF THE CEREBELLUM. 249 



phere. Both central sulci terminate on the dorsum of the supe- 

 rior medullary lamina in the horizontal sulcus. 



(3) Predeclivil Sulcus. (S. pradeclivis, s. primarius] (Figs. 

 76 and 79). Behind the culmen and anterior part of the quad- 

 rangular lobule, a half inch from the anterior border of the ten- 

 tonal surface, there is the predeclivil sulcus. It bounds the 

 declive and posterior part of the quadrangular lobule in front. 

 It ends at the junction of the anterior and middle thirds of the 

 antero-lateral border of the hemisphere in the horizontal sulcus. 

 Embryologically it is second to appear; it is the deepest sulcus 

 of the cerebellum, hence the name, sulcus primarius, given it 

 by Kuithan. Its development begins near the end of the third 

 month in utero (Cunningham). 



(4) The postdeclivil sulcus (s. postdeclivis) (Figs. 76 and 

 79) is located in the posterior cerebellar notch, from which it 

 curves outward and forward in the superior surface of the hemis- 

 pheres. It separates the declivil lobe from the folium vermis, 

 in the worm, and from the superior semilunar lobules in the 

 hemispheres. It ends in the horizontal sulcus at the junction of 

 the posterior and middle thirds of the antero-lateral border. 

 Being behind the crescentic gyri of the quadrangular lobule, 

 this sulcus may be called the sulcus postlunatus. It appears a 

 month later than the predeclivil sulcus. 



Sulci and lobules of the upper surface of the cerebellum from 

 before backward: 



Hemisphere. Worm. Hemisphere. 



Vinculum Lingula Vinculum 



Precentral sulcus 

 Ala Lobulus Centralis Ala 



Posteentral sulcus 



Lobulus quadrangularis, Culmen Monticuli Lobulus quadrangularis, 



pars anterior. pars anterior. 



Predeclivil sulcus 



Lobulus quadrangularis, Declive Monticuli Lobulus quadrangularis, 



pars posterior pars posterior 



Postdeclivil sulcus 

 Semilunaris superior Folium Vermis Semilunaris superior 



Horizontal sulcus 



