Observations upon Presbytes albigena, Gray, and Colobus guereza, Rüppell / by James Murie.

  • Murie, James.
Date:
[1865]
Catalogue details

Licence: Public Domain Mark

Credit: Observations upon Presbytes albigena, Gray, and Colobus guereza, Rüppell / by James Murie. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    genus Semnopithecus present a curious character in the remarkable truncation of the occipital region, S. johnii and S. inauvus having it nearly perpendicular; this gives the cranium, when resting on the mandible, a curious forward expression. P. alhigena, like Cerco- cebus, has this part more shelving; Semnopithecus melalophus and S. obscurus make an approach to this in their contour. The bony palate in Cercocehus fuliyinoms and C. (cthiops is longer and not relatively so broad as in Semnopithecus; the length of the premaxillary produces this. P. albigena has this character well marked. The depth of the lower jaw in Semnopithecus is greatest, the same only being found in the genus Colobus. In the P. albigena and Cer- cocehus the angle of the mandible is less perpendicular and more rounded than in <S. melalophus and <S. obscurus; in many of the other species of Semnopithecus, e.g. in S. johnii and S. entellus, it is even inclined backwards. The teeth in the several genera spoken of are alike in number. The two inner and upper incisors are very much the largest, and project considerably in the two species of Cercocebus examined ; they are precisely similar in the specimen of P. albigena. The Semno- pitheci have all the incisors small and of nearly equal size. In the true species of Semnopithecus, as likewise in Colobus, the canines, as compared with the other teeth, are considerably larger; in Cercocebus and in P. albigena they are not so massive. In the last-named genus and species the cusps of the molars are more rounded, while they are acuminate from before backwards in Sem- nopithecus and Colobus. The upper penultimate molar in Cercoce- bus and the species under consideration is largest; in all the Semno- pitheci the molars are more nearly alike in size. P. albigena and the Cercocebi can hardly be said to possess a fifth cusp in the upper posterior molar; in their lower jaw it is very rudimentary. The lower incisors in P. albigena are more horizontally set, and the ca- nines less curved, than in any of the Semnopitheci; in this respect, and in the less developed size of the lower incisors, the former cor- responds with the genus Cercocehus. The anterior premolar is longest in Semnopithecus, while in the adult P. albigena and the two species of Cercocebus it is rather smaller than the tooth posterior to it. The skull of the young specimen of Presbytes albigena, which has partly been the occasion of the present remarks upon the several genera, shows characters, even in its juvenile condition, which would prevent its being ranked with the genus Semnopithecus, although, at the same time, it must be admitted, as might naturally be ex- pected, that the distinguishing prominent points of difference are not so well marked as in the adult skull of the same s])ecies. Never- theless it bears out, though in a less forcible manner, what I have said, as a whole, of its closer resemblance to Cercocehus than to Semnopithecus. Witli respect to the genus Colobus, the skulls correspond in every jjarticular to tlie genus Seinnopithccus ; the three individual skulls of [4]