58 W. BLAXLAND BENHAM. 



end of the calloso-margiual fissure. This appears to be a slip, 

 yet his measurement of the fronto-Rolandic length given on 

 p. 200 is 54 mm., which is really the distance of the calloso- 

 marginal fissure from the anterior end of the cerebrum. The 

 fissure is thus in front of the middle of tlie cerebrum and not 

 behind it, as Beddard states. 



In the normal chimpanzee here figured (fig. 1) the length 

 of the cerebral hemisphere is 95 mm., the fronto-Rolandic 

 length is 55 mm., so that the Rolandic fissure is behind the 

 middle of the hemisphere. 



The intra-parietal fissure of Turner may be divided, ac- 

 cording to Cunningham, into three constituents : (1) An an- 

 terior post-Rolandic vertical fissure, or " sulcus postcentralis." 

 (2) A more or less horizontal furrow, or " ramus horizontalis " 

 ("interparietal" of Ecker), passing backwards and (3) as a 

 prolongation which bounds the arcus parieto-occipitalis and 

 passes on to the occipital lobe — the " ramus occipitalis.^' 



These three constituents may or may not be continuous in 

 man, and to them is added, usually as a separate furrow, a 

 " superior postcentralis,'' lyiiig more or less parallel to the 

 Rolandic furrow, and dorsal of the inferior postcentralis. 



In "Sally," as will be seen (figs. 10, 11), this is also the 

 arrangement; the inferior postcentralis (p^.) is continued a 

 short distance upward beyond its junction with the ramus 

 horizontalis {p^.), and above this fissure is a small but well- 

 marked furrow, representing the superior postcentralis (p^.) ; 

 this is continuous on the left side with an oblique furrow (p. s.) 

 lying parallel to and above the ramus horizontalis, whilst on 

 the right side the corresponding furrow is parallel with the 

 long axis of the brain. 



This secondary sulcus [p. s.) in the superior parietal lobe 

 is represented in Cunningham's drawing (by the letter c), and 

 is a very constant furrow in the chimpanzee, though variable 

 in form. 



The superior postcentralis {p^.) is in most of the published 

 figures of chimpanzee brains, as well as in several of those exa- 

 mined by me, a much more definite feature (see figs. 30, 36, 



