577 



The fulness of the left occipital pole seems to be the reason for 

 the dextral bending of the superior longitudinal sinus, the flattening 

 of the right pole allowing more room for the bigger sinus on that 

 side. That this is really the case is shown by the fact that in those 

 cases (? perhaps left handed individuals) in which the right area 

 striata spreads on to the caudal surface to a greater extent than it 

 does on the left side, the right occipital pole and the right occipital 



crista lunata 



fossa cort. striatae 



crista calcar. 

 ext. 



Fig. 2. The anterior aspect of the occipital bone moulded to the shape of the 

 brain and membranes shown in Fig. 1. 



squama become more prominent and the superior longitudinal sinus 

 turns to the left. 



Again in those cases in which the occipital poles are symmetrical 

 the superior longitudinal sinus usually bifurcates, one half going to 

 each lateral sinus. This is the condition found in the great majority 

 of Apes, In most Apes the brain and the squama occipitalis are sym-; 

 metrical and the superior longitudinal sinus usually bifurcates. Even- 



Anat. Am. XXX. Aufsätze. 



37 



