OCR Text |
Show 1902.] CARPAL VIBRISS.K IN MAMMALS. 129 character. Broadly speaking, it may be stated that this sense-organ, as we may in the meantime assume it to be, characterizes the Lemurs, Rodents, Carnivora, and Marsupials, and that it is absent in the Ungulates (with the exception of Hyrax) and in the Primates (excluding the Lemurs). The Bats I have not yet studied from this point of view. Of the Insectivora I a m unwilling to speak, as I have examined only Centetes and Erinaceus, which certainly had not this tuft of hairs. As to the Edentata, the representative of this carpal tuft of vibrissa? does appear to exist at least in the Armadillo, Dasypus villosus, as the accompanying figure shows (text-fig. 17, p. 128). But the hairs of that mammal are so coarse that there is but little difference in size and general appearance between the tuft which I compare to those of such an animal as Petaurus sciureus (text-fig. 18, p. 130) and the general hairs of the body. The Sloth (Bralypus tridactylus) has not any traces that I could discover of this " organ." As to other Edentates I have no information to offer, except concerning Manis, where I have found no traces of these hairs. Considered broadly, therefore, this carpal tuft of vibrissa? is of some little use for classificatory purposes, apart from its absence in the Ungulates, where it might well be supposed to be deficient on account of the lack of facilities for use. The most salient feature as to its absence or presence is its nearly universal existence in the Lemurs, and the absolutely universal absence (as far as I have ascertained) in the Monkeys. These two divisions of the Primates, as they are most commonly considered to be, have been brought nearer to each other by recent researches upon certain extinct forms such as Nesopithecus l, and by investigations upon the placenta of Tarsius, which has been shown to be apelike and even human in its characters \ It is not, therefore, without interest to be able to bring forward a character which seems to absolutely distinguish these two divisions of the Primates. Furthermore, it is not a character which has an obvious relation to ways of life : if the tuft of vibrissa? is useful to the Lemurs, it would seem to be equally useful to the Monkeys, many 'of w h o m use their hands as climbing- and grasping-organs in the same way. And I can at least assert, that while the majority of the Lemurs (excluding the Potto and the Loris) which I have examined possess this tuft, the large number of Monkeys, both of the Old and N e w Worlds, which have passed through my hands do not possess it. As to the Marsupials, the genus Macropus, so far as m y present investigations go, stands alone in that the wrist is not provided with this tuft of vibrissa?. I have examined both adults and quite newly born individuals of several species. In the naked new-born young of Marsupials this tuft of vibrissa? is exceedingly i Forsyth Major, P. Z. S. 1899, p. 987. 2 See, for a survey of the-position of Tarsius, Earle, Amur. Naturalist, xxxi. p. 569. PROG. ZOOL. SOC. -1902, VOL. I. No. IX, 9 |