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Show 3 2 8 MR. R. LYDEKKER ON GUEREZA MONKEYS. [Nov. 28, and uniting on the lower part of the back. The culmination o this type of coloration is formed by the White-tailed Guereza (C. caudatus, or cdbocaudatus as it ought to have been ca e ) o the Kilimanjaro district and other parts of Eastern Africa. Heie, as we see from text-fig. 57, the beautiful pendent white mant e has become still longer, and the tail, which is wholly white except for a very small length at the root, is clothed with long pendent hair comparable to the " flag " of a setter ; the cheek- and tliroat-tufts, however, have been completely lost, so that the head is wholly short-haired, with the face and throat white. The difference between the species last-named and the Black Guereza in the matter of colouring is enormous, and yet the transition from the one to the other in this respect is almost complete. In the case of the white-tailed species the excessive Text-fig. 58. Wliite-tliiglied Guereza (Colobus vellerosus). length of the white hair forming the mantle and the tail-fringe appears to have been evolved in order to render the creature as inconspicuous as possible amid the long pendent greyish-white lichens which clothe the branches of the trees of an East African forest. The evolution of such a type is, of course, easy to comprehend; but, as in so many other cases, the difficulty comes in with regard to the purpose of the coloration in the intermediate types connecting this species with the Black Guereza. What purpose do these incipient attempts at the development of a pied coat serve ? The line of evolution culminating in the white-tailed species by no means, however, brings us to the end of the modifications in the colour and local development of the hair in this group of monkeys, |