CEREBRAL CONVOLUTIONS — " SALLY." 85 



parietal fissure (p*.). It is possible that another interpretation might 

 be placed on these fissures. 

 Fig. 32. The hinder part of the right hemisphere, with the operculum 

 turned back. The shaded portions are those now exposed. Cf. Sally's 

 brain. 

 Fig. 33. Projection view of lateral and dorsal surfaces of the frontal 

 lobe of the left side. The " frontalis secundus " is apparently 

 separated into two parts, the hinder {/'.) being joined by the 

 "diagonal is" {d.). 

 Fig. 34. Projection view of the lateral and dorsal surfaces of the 

 right hemisphere. 

 Fig. 35. — Projection view of the dorsal and lateral surfaces of the right 

 frontal lobe of a chimpanzee (Oxford Museum, 947 i.). The dotted ring 

 indicates a slightly injured area. The prsecentralis inferior {p. c. ?.), the 

 ramus horizontalis (A.), and the frontalis secundus (/'.), are continuous. 



Fig. 36. — Dorsal view of the' right hemisphere of Professor Herdman'a 

 chimpanzee. Natural size. It is quite normal. As the membranes were not 

 completely removed it was not possible to completely trace out all the fissures 

 in detail. 



Fig. 37. — Right frontal lobe of the same brain (Professor Herdman's). 

 Fig. 38.— Projection view of the dorsal and lateral surfaces of the left 

 frontal lobe of a chimpanzee (Oxford Museum, No. 947/.)- 



Figs. 39 — 46 illustrate the surface anatomy of the orang's brain. 



Figs. 39 — 41 refer to Rolleston's orang, referred to in the text as II. 

 Figs. 39 and 40 are dorsal views of the right and left hemispheres. 

 Fig. 41. Projection view of the left frontal lobe. The right side of the 

 brain had been dissected, but the upper surface had been sliced off and 

 is preserved. The character of the Affenspalte and neighbourhood 

 may be contrasted with that in Figs. 42 and 43. The peculiar con- 

 dition of the "praecentral fissure" is noteworthy, a. Sulcus prse- 

 centralis margiualis. 

 Figs. 42 — 45 refer to the small orang in the Oxford Museum, referred 



to in the text as I. 

 Fig. 42. Dorsal view of left hemisphere. Natural size. 

 Fig. 43. Dorsal view of right hemisphere. Natural size. The shape of 



the frontal lobe is noteworthy. 

 Fig. 44. Projection view of the left frontal lobe. 

 Fig. 45. Projection view of the right frontal lobe. The dotted portion 



is injured. 

 Fig. 46. A copy of Cunningham's fig. 10, p. 294, for comparison of the 

 frontal convolutions with those in other orangs. I have retained 

 Cunningham's lettering. 



