. Cunningham's Text-book of anatomy. Anatomy. 516 THE NERVOUS SYSTEM. FORE ^. CEREBfMt cerebellum becomes linked to the mesencephalon to co-ordinate the movements of the body which are excited by this part of the encephalon; and later how it becomes associated with the prosencephalon, when the latter becomes respons- ible for the acquisition and control of the most highly skilled actions. For the latter purpose a great pathway of nerve-fibres is laid down to connect the fore-brain with the cerebellum: the terminal stage of this connexion is situated upon the ventral (anterior) aspect of the me
. Cunningham's Text-book of anatomy. Anatomy. 516 THE NERVOUS SYSTEM. FORE ^. CEREBfMt cerebellum becomes linked to the mesencephalon to co-ordinate the movements of the body which are excited by this part of the encephalon; and later how it becomes associated with the prosencephalon, when the latter becomes respons- ible for the acquisition and control of the most highly skilled actions. For the latter purpose a great pathway of nerve-fibres is laid down to connect the fore-brain with the cerebellum: the terminal stage of this connexion is situated upon the ventral (anterior) aspect of the metencephalon in the form of a great mass of transverse fibres. At one time these strands of nerve-fibres were looked upon as a bridge between the two lateral parts of the cerebellum: hence the name pons was applied to them. This term is now applied not only to the fibres themselves, but also to the upward prolongation of the medulla oblongata, to the surface of which they are applied. The subdivision of the rest of the encephalon into mesencephalon and prosen- cephalon develops later and is less fundamental than the primary demarcation between them and the rhombencephalon. The visual apparatus is connected both with the mid-brain and the fore- brain, but at first more intimately with the former, to which nerve pathways are established to convey from the spinal medulla and medulla oblongata sen- sory impressions of touch and hearing. From the alar laminae of the mesen- cephalon there are developed four little hillocks (col- liculi)—corpora quadri- gemina—to receive these Fig. 458.—The Brain of a Human Embryo in the Fifth Week varied impressions and to (from His). enable them to influence A, Brain as seen in profile. B, Median section through the same brain, the actions of the whole M, Mamillary eminence ; Tc Tuber cinereum; Hp, Hypophysis body. Special nerve paths (hypophyseal diverticulum from buccal cavity) ; Opt, Optic stalk ; i • i j n r , TH, Thalamus; Tg, Tegmental
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