388 PHYSIOLOGICAL SERIES. 



The sulci of this brain are much simpler than those of 

 Chrysothiijr.j and the cerebral hemispheres as a whole present 

 a striking resemblance to those of the Lemurs in all points 

 except the difference in shape resulting from the occipital 

 prolongation*. 



The Sylvian and intraparietal elements are here separate. 

 The upper end of the parallel sulcus approaches the Sylvian 

 fissure, as in many Lemurs. 



There are typical sulci rectus and orbitalis. 



Fig. 227. (Nat size.) 



. INTRAPAR. SOLC PAR. 



SULC: ORB. 



SULC PAR OCC. 



Fig. 228. (Nat. size.) 



SULC. CALL. MARG 



SULC. CAL . 



N RHIN.F. 



On the mesial surface the calcarine sulcus is concurrent, 

 as in most Primates, with the retrocalcarine sulcus and the 

 latter is markedly bifid at its posterior extremity. There is 

 no parieto-occipital sulcus on the left hemisphere ; but on 

 the right there is a shallow groove in the position where 

 this sulcus may make its appearance. There is u we II- 



* This likeness becomes all the more significant when it is recalled that 

 in some of the Prosiraice the restriction of the caudal pole is a secondary 

 modification which occurs during ontogeny. Thus, among a number of 

 skulls kindly lent me by Dr. Forsyth Major was ,one of a Propithecus 

 coronattis 15 days old, from which it was evident that the cerebral hemi- 

 spheres must have almost wholly covered the cerebellum. 





