HABITS.--The Bald Chimpanzee showed in captivity a disposition to live on animal food, which the Common Chimpanzee never does. "Sally" had also the singular habit of producing pellets, resembling the castings thrown up by Raptorial birds; they were composed of feathers (of the birds she had eaten) and other indigestible substances taken with her food. Moreover, "Sally," as this Chimpanzee, now famous in the annals of zoology, was named, was an expert rat-catcher, and caught and killed many rats that entered her cage. "Her intelligence was {201}far above that of the ordinary Chimpanzee. With but little trouble she could be taught to do many things that require the exercise of considerable thought and understanding." (_Bartlett._) In general habits _A. calvus_ differs, so far as known, in no respect from _A. troglodytes_. It was on this Ape that the late Dr. G. J. Romanes, attracted by its high intelligence, made his interesting psychological experiments, which are related in the Proceedings of the Zoological Society for 1889. "Her intelligence was conspicuously displayed by the remarkable degree in which she was able to understand the meaning of spoken language--a degree fully equal to that presented by an infant a few months before emerging from infancy, and, therefore, higher than that which is presented by any brute, so far at least as I have met with any evidence to show. Having enlisted the intelligent co-operation of the keepers, I requested them to ask the Ape repeatedly for one straw, two straws, or three straws. These she was to pick up and hand out from among the litter of her cage. No constant order was to be observed in making these requests, but whenever she handed a number not asked for, her offer was to be refused, while if she gave the proper number her offer was to be accepted, and she was to receive a piece of fruit as payment. In this way the Ape was eventually taught to associate these three numbers with their names.... As soon as the animal understood what was required, and had learnt to associate these three numbers with their names, she never failed to give the number of straws asked for. Her education was then extended in a similar manner from three to four and four to five straws." "Sally" rarely made mistakes up to that number, but above five and up to ten, to which one of the keepers endeavoured to advance her education, the result is uncertain. {202}"It is evident that she understands the words seven, eight, nine, and ten, to betoken numbers higher than those below them, and when she was asked for any of these numbers above six, she always gave some number over six and under ten. She sometimes doubled over a straw to make it present two ends, and was supposed to hasten, with the small stock of patience she possessed, the attainment of her task." Dr. Romanes was disposed to think that the uncertainty which attended her dealing with the numbers six and seven was