176 



COMPARATIVE ANATOMY 



The pineal body is displaced downwards by the hemispheres'' 

 and lies against the anterior part of the mid-brain, not reaching, 

 to the roof of the skull. Its bifurcated peduncle connects it 



xJJa ^^ TcJt ^ 



IM' 



-Jiff 



EiG. 145. — Human Ekain. (Median longitudinal vertical section. ) 

 (Mainly after Reicliert.) 

 VH, cerebrum ; To, optic thalamus (thalamencephalon), with the middle commis- 

 sure (Cm); Z. pineal body; T, infundibulum ; H, pituitary body; ME, 

 corpora bigemina, with the aqueduct of Sylvius (Aq), anterior to which is 

 seen the posterior commissure (Cp) ; HH, cerebellum ; NH, medulla oblongata, 

 with the pons Varolii (P) ; i?, spinal cord ; B, corpus callosum ; G, fornix, 

 which extends antero-ventrally to the lamina terminalis (Col), in the upper 

 part of which is seen the anterior commissure (Co), and between the latter 

 and the optic thalami (To) the foramen of Monro (FM) ; Tcli, tela choroidea ; 

 /, olfactory nerve ; //, optic nerve. 



Fig. 146. — CoxvolutiOns of the Human Bkaix. (After A. Ecker.) 



Lf, frontal lobe ; L-p, parietal lobe ; Lo, occipital lobe ; T, temporal lobe ; n, h, c, 

 superior, middle, and inferior frontal gj'ri ; X, $, anterior and posterior 

 central convolutions, separated from one another by the fissure of Rolando 

 (i?) ; cm, the calloso-marginal sulcus on the dorsal surface ; P, P^, superior and 

 inferior parietal gyri separated from one another by the interparietal fissure 

 (/) ; Po, parietal-occipital fissure ; FS, Sylvian fissure ; 1 to 3, superior, 

 middle, and inferior temporal convolutions ; HH, cerebellum ; NH, medulla 

 oblongata ; E, spinal cord. 



with the roof of the thalamencephalon and contains nervous 

 substance ; its distal end has the form of a rounded or oval sac, 

 consisting of compact epithelial tissue and containing concre- 

 tions. No indication of a parietal organ can be recognised. 



