1287 
A contrast of the same nature, but not so great, exists between 
the Orang utan and the Chimpanzee. The slow, clumsy, deliberate 
movements, without jumps, of the Malay anthropoid are indeed 
sharply distinguished from the mode of moving of his African rela- 
tion, the Chimpanzee, which is an excellent climber, swings over 
large distances from one branch to another, and jumps with wonder- 
ful agility. But though the body weight of the Orang utan is cer- 
tainly a third greater than that of the Chimpanzee, the brain weight 
of the two species is the same in the females, in the males that of 
the Orang utan is only little more. 
SELENKA’) determined the mean capacity in the sexes of the Orang 
utan at 455 and 390 cm’., and of the Chimpanzee at 420 and 390 cm’. 
To him in the Anthropoids ‘““Muskelmasse und Hirngrösse” seem 
“daher in direkter Beziehung zu stehen”, because the “rein geistigen 
Fähigkeiten wohl als nabezu gleich angenommen werden dürfen.” 
It also strikes him that in Orang utan “Skelet und Muskulatur des 
Männchens” are “ausserordentlich viel stärker als die des Weibchens.” 
It is now remarkable that according to Fick’s®) research the total 
muscle weight in reference. to the body weight is much less, the 
fat percentage on the other hand, greater in Orang utan than in Man. 
We meet here with the same difference in the composition of the 
body weight as between woman and man, and here too we see this 
accompanied on one side by a brain weight low in comparison with 
the body weight; for we may assume that the Chimpanzee, like 
most other Apes, is more muscular than the Orang utan.*) 
Among the American Monkeys, Saimiri (Chrysothrix) is further 
much quicker and nimbler in its movements than Leontocebus 
(Midas) and Callithrix (Hapale); accordingly its cephalisation coeffi- 
cient is considerably higher. 
In conclusion attention may still be drawn in this connection to 
the high cephalisation of the Seals and to the considerably higher 
cephalisation of the Toothed Whales than that of the Whalebone 
Whales. For Balaenoptera musculus I calculated the coefficient 0.384 *). 
1) Emit SELENKA, Menschenaffen. Zweite Lieferung, p. 99—100. Wiesbaden 1899. 
*) R. Fick, Vergleichend anatomische Studien an einem erwachsenen Orang- 
Utang. Archiv fiir Anatomie und Entwickelungsgeschichte. (W. His). Leipzig. 
Jahrgang 1895, p. 68—69 and p. 73. The examined specimen was a male Orang utan. 
3) Euc. DuBois, Comparison of the Brain Weight in Function of the Body- 
Weight, between the Two Sexes. These Proc. Vol. XXI, No. 6 and 7, p. 850 
seq. 1918. — H. WELCKER (loc. cit. p. 41) found the relative muscle weight 
of a male “Inuus cynomolgus” greater than the mean of the male in Man. 
4) The Significance of the Size of the Neurone and its Parts. These Proc. Vol. 
XXI, No. 5, p. 724. 
