1899.] DK. A. KEITH ON THE chi:mpanzees. 297 



Mr. Mackay, whom I believe to be reliable, adding so consider- 

 ably to our knowledge of the habits of the Chimpanzee that I 

 wish to give them here. 



She is, so far as I know, the first Cliimpanzee that has ever 

 lived long enough in captivity to complete its permanent dentition. 

 All her permanent teeth have cut, with the doubtful exception of 

 the third molar on one side, and it becomes important to determine 

 her age so as to ascertain the period of life at which these animals 

 attain a complete set of permanent teeth. Man attains his about 

 the twenty-second year, but the Chimpanzee evidently much 

 earlier. Johanna has been twelve years in captivity — six years in 

 Messrs. Barnum and Bailey's Menagerie, six years in the Zoological 

 Gardens at Lisbon ; and we may infer, as it is the common age, 

 that she was one or two years old when Portuguese traders brought 

 her there from the West Coast of Africa, probably liOango. When 

 she came into his care six years ago, Mr. Mackay is positive she 

 had then cut all her permanent incisors. Prom the appearance of 

 the third molars, I think the permanent dentition has been 

 completed very recently, so that we may accept the 12th or 13th 

 year as the terminal period of the Chimpanzee dentition. As is 

 usual in the female Chimpanzee, the canine teeth cut before the 

 last molars. There are only two other records of the period at 

 which the Chimpanzee teeth erupt. One is the case of '• Sally "\ 

 She was probably ten years of age when she died ; the permanent 

 premolars had cut, but the canines and the second and third molars 

 had not appeared. Ehlers '^ also records the case of a Chimpanzee 

 in which the permanent dentition was being completed about the 

 11th or 12th year by the eruption of the canine and last molar 

 when the animal died. 



2. Menstruation. 



Little is known concerning the menstruation of the Anthro- 

 poids. The only observation is that of Ehlers ^, of a Chimpanzee 

 which began to menstruate about the tenth year, and continued, 

 until it died two years later, to show a monthly discharge. 

 Mr. Mackay's observation on " Johanna " verifies Ehler's state- 

 ment ; she began to show a monthly discharge when she ^^'as 

 believed to be ten years old. The discharge appears every 28th 

 day, and lasts for three days. It is sanguineous in colour, 

 profuse, amounting to perhaps 4 or 6 oz., staining freely her 

 skirt. She is then very irritable. Eor 6 to 8 days before the 

 discharge appears she is in heat, the genital labia are turgid and 

 swollen ; the nipples are fuller and more erect. When the 

 discharge appears, the state of turgescence in the pudendal organs 

 passes away. She shows a friendly disposition to men rather than 

 to women. She frequently plays with her nipples, but has 



^ Beddard, F. " Contributions to the Anatomy of the Anthropoid Apes," 

 Trans. Zool. Soc. Lond. 1892, vol. xiii. pp. 177-218. 



^ Ehlers, P. " Beitrage zur Keuntniss des Gorilla und Chirapanse," Abh. 

 pbys. CI. Ges. Wiss. Gottingeu, ISSl, Bd. xxviii. Ko. 1, 77 pp., 4 pis. 



