50 



THE MAMMALIAN ORDER PRIMATES [SECT. A 



CENTRAL SULCUS 



SULCUS RECTUS 



ARCUATE SULCUS 



ORBITAL SULCUS " 



ORBITAL SULCUS 



NTRAPARIETAL SULCUS 



INC. PAR. OCC. 



PARALLEL SULCUS 



FISSURE OF SYLVIUS 



PAR I ETO- OCCIPITAL 

 FOSSA 



CALCARINE 



SULCUS - _ 



COLLATERAL SULCI i_ 



- - CALLOSO- 

 MARGINAL 

 SULCUS 



_ SULCUS 

 GENUALIS 



INCISURA TEMPORALIS OR RHINAL 

 FISSURE 



Fig. 23. The left cerebral hemisphere of an American (Platyrrhine) ape, Ateles 

 variegatus: the lateral and mesial aspects of the hemisphere are shewn. (Mus. 

 Anat. Cant.) 



