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Show 1873.] CHARACTERS IN THE CHIROPTERA. 249 be found to possess structural differences depending on sex, as have been described in other orders of Mammalia. It remains now to consider the secondary sexual differences arranged under the second head-namely, differences in the colour of the fur. As the colour of the fur in Bats, as in other mammals, varies very considerably according to age, season, and locality, it is necessary in comparing males and females to pay particular attention to this fact. Thus the common Flying Fox of Europeans in India, Pteropus medius, Temm., varies considerably ; and the difference in the colour of tbe fur of individuals obtained from different localities or the same locality has caused some zoologists to rank them as distinct species, though perfectly similar in structure *. There is probably scarcely a single species of Bat to which this rule does not apply; but the variability of colour is often not noticeable in those in which the fur is of a very dark shade. It is interesting to observe how Dr. Fitzinger, either from imperfect knowledge or from want of due appreciation of these facts, has reproduced the mistakes of former observers by republishing the names and descriptions of species previously recognized as synonyms of other species, in some cases by the authors themselves. Thus four species of Rhinolophus (Aquias) are recognized and described (op. s. c. p. 192 et seq.) which differ from one another only in the colour of the fur. And so we have, according to Dr. Fitzinger, " the grizzled leaf-nosed Bat" (Aquiasluctus, Temm.), "the reddish leaf-nosed Bat" (A. eudouxii, Laplace), "the dark red leaf-nosed Bat" (A. morio, Gray), and " the black leaf-nosed Bat " (A. perniger, Hodgs.). Except the second named, these forms of R. luctus are in the Indian Museum, and they have all been obtained at Darjeeling. Similarly Kelaart's R. rubidus et fulvidus, which Blyth had shown to be indentical with R. affinis, Horsf, are restored on the same grounds- difference in colour. The examination of many specimens of these Bats has shown me that, where male and female specimens of the same species have been obtained at the same time and place, the lighter-coloured specimens are invariably males. This confirms Dr. J. A. Allen's observation regarding some species of American Bats*)". Thus a male specimen of R. luctus from Darjeeling, in the Indian Museum, answers in every respect to the original description of P. morio, Gray ; while several females from the same locality, and taken at the same time, are wholly black, and belong, therefore, according to Fitzinger, * Dr. J. E. Gray notices the variability of colour in specimens of the same species found in the same locality as follows :-" There is a general similarity in the colouring of the majority of the species; specimens found in the same locality or island often vary considerably from one another, even when the examination of the skull and teeth show that they are of the same species. On the other hand, specimens from different localities often resemble one anotber so much in their external colouring that it is difficult to distinguish them in any description that can be made ; but when the skulls and teeth are examined they prove to be very different species." ('• Revision of the Genera of Pteropine Bats," Proc Zool. Soc. Lond. 1866, p. 65.) t Quoted by M r . Darwin, 'Descent of Man,' vol. ii. p. 286. |
