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Show 296 DR. A. KEITH ON THE CHIMPANZEES. [Mar. 7, 1. On the Chimpanzees and their Relationship to the Gorilla. By A R T H U R KEITH, M.D., F.Z.S. [Eeceived March 7, 1899.] (Plate XX.) At the present time there is in the Menagerie of Messrs. Barnum and Bailey an adult female anthropoid ape, known by the name of " Johanna," regarded by its owners as a Gorilla, but which, there can be no doubt, is in reality a Chimpanzee. No difficulty has ever been experienced in distinguishing between the male Gorilla and the male Chimpanzee, nor between the females when an anatomical investigation has been possible; but on several occasions, as in the case of this Ape, living female Chimpanzees have been mistaken for Gorillas. There is the classical case of " Mafuka,"1 of the Dresden Zoological Garden. " Johanna" shares all the features of "Mafuka"; she answers to the description given by D u Chaillu of the species he names " Troglodytes kooloo-kamba" 2. The animal dissected and described by Gratiolet and Alix 3 under the name of T. aubryi was also of the same variety. " Johanna " is of interest because she represents a variety of Chimpanzee Avhich approaches the Gorilla in so many points that it is evident the characters which separate the two African anthropoids are not so well marked as many suppose. The difficulty of distinguishing the one from the other, as shown by a recent communication by Mr. Duckworth4 to this Society, is such that it has become necessary to sum up, from a much wider examination of material than has ever been at anyone's disposal before, the structural and physiological differences which separate the Gorilla from the Chimpanzee, and at the same time to sum up the evidence as to the existence of one or more species of Chimpanzee. Some five years ago, on working minutely over all the anthropoid material in the collections of the Natural History Museum at South Kensington and the Museum of the Boyal College of Surgeons, which contain the skulls of 31 Gorillas, 44 Chimpanzees, 73 Orangs, and 56 Gibbons, I \Aas struck by the fact that nearly all the characters which had been used to differentiate species were points Avhich varied in structure and form Avith age, sex, and the individual, but I have never had any difficulty in distinguishing betAveen the skulls, even of foetal Gorillas and Chimpanzees. 1. The Eruption of the Permanent Teeth in Chimpanzees. Mr. Duckworth has promised the Society a full description of " Johanna," but I learned certain facts from her keeper, 1 KEITH. 'Introduction to the Study of Anthropoid Apes,' pp. 8, 23. London,1897. 2 Du CHAILLU. ' Explorations and Adventures,' 1861, p. 360. 3 GKATIOLET et ALIX. " Recherches sur l'Anatomie du Troylodytes aubryi," Nouv. Archiv. du Mus. Hist. Nat. 1866, t. ii. pp. 1-263. 4 W. L. H. DUCKWORTH. P. Z. S. 1898, p. 989. |