52 W. BLAXLAND EENHAM. 



add. He found that the brain " weighed, after removal of the 

 pia mater and after an immersion of four months in spirit, 

 8f oz. ; it had been allowed to dry for an hour and a half 

 before weighing, it was then damp, but not wet/^ 



He gives the weights of brain of two other chimpanzees 

 (T. niger) as 6^ oz. and 6f oz. 



The brain described by Miiller weighed 6-|- oz. (213 grammes), 

 whilst that described by Symington (10), tliough not bearing 

 any particular resemblance to '^Sally's" brain, weighed as 

 much as 8^ oz. after preservation in spirit ; both these authors 

 tabulate the weights of the brains previously recorded. Mar- 

 shall's specimen (1861) (2) weighed under similar circumstances 

 as much as 9 oz. But the weight of the brain fresh is con- 

 siderably more ; thus Symington's was 13 oz., Marshall's 15 

 oz., and Chapman's (7) 10 oz. 10 grains. In all these cases 

 the animal was young, and Symington suggests from analogy 

 with man, and from comparison of cranial cavities of young 

 and adult chimpanzees, that the weight of the brain in the 

 latter is 15 oz. 



I have not deemed it necessary to weigh the various brains 

 to which I shall have occasion to refer. 



Beddard gives the length of " Sally's " brain as 103 mm., 

 and that of the hemisphere alone as 100 mm. Miiller's 

 measured 92 mm. and Symington's 95 mm., so that " Sally's " 

 appears to be the largest hitherto carefully measured, as one 

 would expect, since the animal is the oldest chimpanzee whose 

 brain has been described. 



The general appearance of the brain is more like that of man 

 on a small scale than is that of an ordinary chimpanzee (see 

 figs. 1, 2, 3). The frontal lobes are wider and more rounded 

 anteriorly. But we must not lay too much stress on this point, 

 for there is considerable variation in the shape of the frontal 

 lobes when many chimpanzee brains are examined. There is 

 one point which Beddard remarks upon, and which dillercn- 

 tiates " Sally's " brain from any other chimpanzee's brain 

 described and figured, viz. the very slight " keel" or ridge on 

 the inferior or orbital surface of the frontal lobes where they 



