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Show 1899.] DR. A. KEITH ON THE CHIMPANZEES. 299 and utters a cry beginning with a IOAV hoo, hoo. gradually raising it in volume to a loud climax. I do not think her cry differs from that of the young Anthropopithecus niger in character; what is peculiar in her cry may be put down to her more advanced age. The Chimpanzee cry is very different from the howl of the Gorilla; " Johanna " does not beat her breast, as the Gorilla does, when in temper. She allows her keeper, only, to handle her ; she is vicious towards others and takes her revenge on an offender by suddenly throwing handfuls of litter at him from the floor of her cage. She has never been given an opportunity of manifesting any nest-building habit, and the experiment seems AA'ell worth trying. On making her escape on one occasion she was found carrying away large pieces of wood on her shoulder. She is fed mostly on fruit. A day's rations consists of :- 2 dozen bananas. 1 ,, oranges. 1 ,, raw eggs. | „ apples. Lemons. Carrots. Coffee, tea, port wine. Toast and sandwiches. When given an opportunity, she caught, plucked, and ate a sparrow, but she rejects no pellets from the stomach, as was the case with " Sally." She sleeps on her side and spends the day sitting on a broad box, with her legs spread out in front and her arms on her belly. There is a very marked difference betAveen the size of the brain of the Gorilla and Chimpanzee. The average cranial capacity of seven adult female Gorillas I found to be 450 c.c.; of ten similar Chimpanzees 364 c.c.; but although the average is greater in the Gorillas, the highest of Chimpanzees exceeded the lowest of the Gorillas, so that the size of brain is not a feature that can be used to discriminate the one from the other. The average cranial capacity of six adult male Gorillas is 530 c.c.; of sixteen male Chimpanzees 405 c.c. The smallest Gorilla skull had a greater capacity than the largest Chimpanzee. The largest Chimpanzee skull measured 460 c.c. The cranial capacity appears to be diagnostic for the males of those animals. A n important distinction appears in the size of the brain as in the general appearance of those Anthropoids ; the sexual difference is much more marked in the Gorilla than in the Chimpanzee. The cranial capacity of those animals, stated in c.c, may be taken as representing the brain-weight, stated in grammes 1; but in comparing the relative size of the brains of the Gorilla and Chimpanzee a greater deduction has to be made from the brain of the Gorilla than from that of the Chimpanzee, owing to the much 1 KEITH. Journ. Anat. & Physiol. 1895, n. s., vol. ix. pp. 282-303. |