Section 122. the Cerebellum (metencephalon) Consists of a Central

mass, the vermis (v.cbm.), and it also has lateral lobes (l.l.), prolonged into flocculi (f.cbm.), which lastare -em-bedded in pits, the periotic bone, and on that account render the extraction of the brain from the cranium far more difficult than it would otherwise be. The roof of the hind-brain, before and behind the cerebellum, consists of extremely thin plates of nervous matter. Its floor is greatly thickened to form the mass of the medulla, and in front a great transverse track of fibres is specialized, the pons Varolii (p.V.). Its cavity is called, the fourth ventricle.