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Show 1 9 0 5 .] MR. R. LYDEKKER ON GUEREZA MONKEYS. 3 2 5 The following papers were read :- 1. Colour Evolution in Guereza Monkeys. By R . L y d e k k e r . [Received November 7, 1905.] (Text-figures 54-58.) An interesting example of the progressive evolution of specialised features in colouring (if we may thus term combinations of black and white) is afforded by the black and black-and- white African long-haired monkeys included in the genus Colobus, and which may be collectively designated Guerezas, although the name " guereza" refers properly only to the northeast African representative of the group. Beginning at one end of the series, we have the Black Guereza {Colobus satanas), of West Africa, which, as shown in text-fig. 54, Text-fig. 54. Black Guereza (Colobus satanas). is wholly black with tufts of long hair on each side of the face and throat, a pointed crest on the crown of the head, and the long tail short-haired from base to tip. Following on this we may take a variety of the Mantled Guereza from East Central Africa which I have recently described as Colobus palliatus cottoni, in which the face-tufts, chin, and narrow pendent tufts of long hair on the shoulders are white, while the terminal half of the tail is grey with a white tip, which shows a slight tendency to |
