250 THE RHOMBENCEPHALON. 



Lobes of Superior Surface (Figs. 76, 77 and 79). The lobes 

 of the superior surface of the cerebellum should be studied first 

 in a median section, where the branches of the medullary body 

 (lamina medullares) will guide the student and where the sulci 

 are most easily identified. These lobes include the divisions 

 of the worm and of the hemispheres, and are five in number. 



Lingula and Vincula, Lobus Lingulae. The lingula is a 

 very small lobule of the vermis entirely concealed in the anterior 

 cerebellar notch by the overhanging central lobule. It is a tongue- 

 shaped group of four or five rudimentary transverse gyri. It 

 rests upon the superior medullary velum, with which its white 

 center is continuous. Laterally, the lingula tapers off and is 

 sometimes represented in the hemisphere by a very thin gyms 

 called the vinculum lingulas. The vinculum is bounded by the 

 brachium conjunct! vum cerebelli in front, and by the precentral 

 sulcus behind. The precentral sulcus separates the lobe of the 

 lingula from the central lobe. 



Central Lobule and Alae, Lobus Centralis (Figs. 77 and 

 79). The lobulus centralis is situated between the precentral and 

 posteentral sulci, in the anterior cerebellar notch. It covers the 

 lingula and in turn is overhung by the culmen. Four or five 

 small transverse gyri make it up. On sagittal section, it is seen 

 to form a single branch of the corpus medullare (arbor vitse). 

 The gyri of the central lobule, continuing along the anterior cere- 

 bellar notch into either hemisphere, form a triangular or wing- 

 like lobule, the ala (ala lobuli centralis). 



Culmen and Anterior Part of Quadrangular Lobules, 

 Lobus Culminis (Figs. 76 and 79). In the culmen monticuli the 

 surface of the cerebellum reaches its highest elevation. It is a 

 large lobule and occupies half of the tentorial surface of the worm. 

 It is made up of three or four prominent gyri, which extend 

 laterally into the hemispheres; and, in each, forms the anterior 

 part of the quadrangular lobule. The pars anterior lobuli quad- 

 rangularis occupies about one-third of the tentorial surface of 

 the hemisphere. The predeclivil sulcus separates the culmen 

 and the pars anterior of either side (the lobe of the culmen) from 

 the declivil lobe. 



