DEEP PARTS OF THE CEREBRUM. 553 



In the human brain the quadrigeminal bodies are small in comparison 

 with those of animals. In ruoainant, soliped, aud rodent animals, the 



Fig. 377. 



To, 



Fig. 377. VIEW OP THE MEDULLA OBLONGATA, PONS VAROLII, CRURA CEREBRI, AND 

 CENTRAL PARTS OF THE ENCEPHALON FROM THE RIGHT SIDE. 



The corpus striatum and thalamus opticus have been preserved in connection with the 

 central lobe and crura cerebri, while the remainder of the cerebrum has been removed. 



St, upper surface of the corpus striatum ; Th, back part of the thalamus opticus ; G, 

 placed on the middle of the five or six convolutions constituting the central lobe or island 

 of Reil, the cerebral substance being removed from its circumference ; Sy, fissure of 

 Sylvius, from which these convolutions radiate, and in which are seen the white striae of 

 the olfactory tract ; I, the olfactory tract divided and hanging down from the groove in 

 the convolution which lodges it ; II, optic nerves a little way in front of the commissure ; 

 a, right corpus albicans with the tuber cinereum and infundibulum in front of it ; h, 

 hypophysis or pituitary body ; e, external, and i, internal corpus geniculatum at the back 

 part of the optic tract; P, peduncle or crus of the cerebrum ; /, fillet; III, right oculo- 

 motor nerve ; p, pineal gland ; q, corpora quadrigemina ; IV, trochlear nerve rising from 

 -y, the valve of Vieussens ; V, placed on the pons Varolii above the right nervus trige- 

 minus ; s, the superior, wi, the middle, aud in, the inferior peduncles of the crus cere- 

 belli cut short ; VI, the sixth nerve ; VII a, facial nerve ; VII b, auditory nerve ; on 

 the medulla oblongata the parts are indicated as follows : VIII, placed opposite to the 

 cut end of the pneumo-gastric nerve ; a, the glosso-pharyngeal ; and b, the uppermost 

 fibres of the spinal accessory nerve ; IX, the hypoglossal nerve ; p a, anterior pyramid ; 

 o, olivary body; a r, arciform fibres; p p, posterior pyramid; r, restiform body; tr, 

 eminence corresponding to the tubercle of Rolando ; at the commencement of the spinal 

 cord, ca, indicates the anterior, cp, the posterior, and cl, the lateral columns; C I, 

 anterior and posterior roots of the suboccipital or first cervical nerve. 



o o 



