OEREBEAL CONVOLUTIONS — " SALLY." 83 



Fig. 12. View of the right hemisphere, seen laterally but also with the 

 upper surface shown, so that the result is a projection of the surface. 

 The shaded portion indicates the orbital surface of the frontal lobe. 



Fig. 13. The left frontal lobe, viewed laterally but with the dorsal surface 

 shown. Rather less of the orbital region is represented than in Fig. 12. 



Fig. 14. Inner (mesial) surface of the hinder part of the left hemisphere, 

 in order to exhibit the condition of the parieto-occipital fissure (P. 0.), 

 which is nearly divided into two parts {lat.p. o.) passing on to the 

 upper surface, and (nies. p. o.) at a. ; the gyrus intercuneatus, however, 

 does not come quite up to the surface, b. and c. Branches of the 

 mes. p. 0. in the prsecuneus. In this and the following figure it will be 

 noted that the calcarine and parieto-occipital fissures meet. 



Fig. 15. Inner (mesial) surface of the hinder part of the right hemi- 

 sphere. The gyrus intercuneatus ((Z.) is here superficial, and divides 

 completely the parieto-occipital fissure into the mesial {mes. p. o.) and 

 lateral {laL p. o.) portions. 



Fig. 16. — Dorsal view of the left hemisphere of a human brain (Oxford 

 Museum, No. 950), reduced from a photograph, in order to illustrate the con- 

 dition of the parieto-occipital fissure. It is to be compared with the right side 

 of " Sally's " brain, m. p. o. and /. p. o. are the two parts of the parieto- 

 occipital fissure, a. is the gyrus intercuneatus. The " transverse occipital " 

 is labelled " Affenspalte " for comparison. 



Fig. 17. — The hinder part of the left hemisphere of the human brain figured 

 by BischofF (tracing), for comparison with that of " Sally," more especially 

 with regard to the condition of the "Affenspalte " or transverse occipital. 



Fig. 18. — The hinder part of the right hemisphere of the human brain 

 figured by BischofF (tracing), for comparison with that of " Sally." 



Fig. 19. — A tracing of the chimpanzee brain figured by Broca. a. a. a., b. b. b. 

 The Affenspalte on right and left side respectively, divided into two. 2. 2. 

 The " arcus." I. I. I. The occipitalis primus. 



Fig. 20. — The right hemisphere of the chimpanzee's brain presented by 

 Professor John Marshall to the Royal College of Surgeons in 1891. On the 

 left side an operculum is well and normally developed, and hides the Affen- 

 spalte ; but on the right side this fissure is exposed by the diminution of the 

 operculum, and in this resembles " Sally." 



Fig. 21.— The inner (mesial) surface of the hinder part of the right hemi- 

 sphere of the brain. No. 947 «., represented at fig. 30. The parieto-occipital 

 fissure is quite simple. 



Fig. 22. — The left hemisphere of a chimpanzee's brain (Oxford Museum, 

 No. 947/.), to illustrate the condition of the parieto-occipital fissure and 

 neighbouring parts. The operculum conceals the Affenspalte and some portion 

 of the lateral parieto-occipital. 



