524 



CEREBRUM. 



THE PRIMARY OR INTERLOBAR FISSURES are three in number, the 

 fissure of Sylvius, the fissure of Rolando (or central sulcus), and the 

 parieto-occipital fissure. 



The fissure of Sylvius (see figs. 375, s, and 370) commences on 



Fig. 368. 



Fig. 368. — Outline of the Cekebkuji as seen fkoji the left side. | 



F, frontal lobe ; P, parietal lobe ; T, temporal lobe ; 0, occipital lobe ; R, R, fissure 

 of Rolando ; s, s, fissure of Sylvius, posterior division ; s, its anterior division ; C, at 

 the junction of the two, marks the place of the central lobe or convolutions of the island 

 of Reil ; p, the place of the vertical or occipital fissure ; a, a', a", superior, middle, and 

 inferior frontal convolutions ; a*, orbital convolutions ; x, x, transverse frontal fissure ; 

 A, ascending frontal convolution ; B, ascending parietal convolution ; b, superior parietal 

 lobule ; b'', supra marginal convolution ; b'", angular convolution ; c, c', c", upper, 

 middle and lower temporo-sphenoidal convolutions; d, d', d", upper, middle and lower 

 occipital convolutions. 



Fig. 369. 



Tt.L. 



Oc.Ii. 



Fig. 369. — Figure of Bkain of Chimpanzee (from Gratiolet). 



Fr. L., frontal lobe ; Par. I., parietal lobe ; Oc. L., occipital lobe ; Temp. Sph. L., 

 temporo-sphenoidal lobe ; Sylv. f. , fissure of Sylvius ; /. Sy. a. , /. Sy. p. , its anterior and 

 posterior limbs ; /. Rol., fissure of Rolando ; tr. fr. /. , transverse frontal fissure ; int- 

 par. /., intra-parietal fissure ; par.-oc. /., parieto-occipital fissure. 



