46 ON THE AFFINITIES AND DIFFERENCES BETWEEN THE 



Fig. 4 b. — Left Cerebral Hemisphere of Chimpanzee, Simla troglodytes. Both 

 bridging convolutions are concealed within the fissure E. 



Fig. 5 a.— Left Cerebral Hemisphere of Mandrill, Cynocephalus mormon, similarly 

 lettered and numbered. The great size of the occipital lobe is well seen. 



Fig. 5 5. — Left Cerebral Hemisphere of American Spider Monkey, Ateles belzebuth. 

 Both bridging convolutions are seen to come to the surface at a and /3. (After Gratiolet.) 



