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Show 286 SEXUAL SELECTION: MAMMALS. PART II. been acquired as ornaments; and this I ]mow is the opinion of som(~ naturalists. If this view bo cor~·ect, there can be little donbt that th y have been acquued, or at least modified, through sexual selection. Colour of the Hai1· and of tlze Naked Skin.---:I will' first give briefly all the cases known to me, of m~le quadrupeds differing in colonr from tho females. W1th Marsupials, as I am informed by Mr. Gould, tl10 sexes rarely differ in tbis respect; but the. great red k~ngaroo' offers a striking exception, "delicate blue bemg " the prevailing tint in those parts of .the ~emale, "which in the male are reel." 19 In the D~delplns opossum of Cayenne tho female is said to be a little more rod than the male. With Rodents Dr. Gray remarks: ''African squirrels, especially those found in tho tropic: cal regions, have the fur much brighter and more "vivid at some seasons of tho year than at others, and "the fur of the male is generally brighter than that " of the female." 20 Dr. Gray informs me that he specified the African squirrels, becausf:': ~rom ~heil: unusually bright colours, they best exhibit tlns difference. rrhe female of the Mus mimdus of Russia is of a paler and dirtier tint than the male. In some few bats the fur of the male is lighter and brighter than in the female. 21 The terrestrial Carnivora and Insectivora rarely exhibit sexual differences of any kind, and their colours are almost always exactly the same in both sexes. The 10 Osph?-anter rufus, Goultl, 'Mammals of Australia,' vol. ii. 1863. On the Didelphis, D c~marcst, 'l\1:;1mmnlogic,' p. 256. 20 'Annals and Mag. ofNnt. Ilbt.' Nov. 1867, p. 325. On the Mus minutus, Desmarest, 'Mnmmalogic,' p. R04. 21 J. A. Allen, in 'Bulletin of Mus. Comp. Zoolog. of Cambridge, United States,' 18GD, p. 207. C11Ar. XVIII. ORNAMENTAL COLOUHS. 287 ocelot (Felis pardalis), however, offers an exception, for the colours of the female, compared with those of the male, are "moins apparentes, le fauve ctant plus terne, " le blanc moins pur, les raios ayant moins de largeur "et les taches moins de diametre." 22 The sexes of the allied Felis mitis also differ, but even in a less degree, the general hues of the female being rather paler than in the male, with the spots less black. The marine Carnivora or Seals, on the other hand, sometime::. differ considerably in colour, and they present, us we have already seen, other remarkable sexual differences. Thus the malo of the Otaria nigrescens of the southern hemisphere is of a rich brown shade above; whilst the female, who acquires · her adult tints earlier in life than the male, is dark-grey above, the young of both sexes being of a very deep chocolate colour. The male of the northern Phoca groenlandica is tawny grey, with a curious saddle-shaped dark mark on the back; the female is much smaller, and has a very different appearance, being "dull white or yellow" ish straw-colour, with a tawny hue on the back;" the young at first arc pure white, and can "hardly be dis" tinguished among the icy hummocks and snow, their " colour thus acting as a protection." 23 With Ruminants sexual differences of colour occur more commonly than in any other order. A difference of this kind is general with tho Strepsicerene antelopes; thus the male nilghau (Portax picta) is bluish-grey and much darker than the female, with the square white patch on the throat, the white marks on the fetlocks, 22 Dcsmarest, 'Mammalogie,' 1820, p. 223. On Felis mitis, Rengger, iLiu. s. ID4. 23 Dr. Murie on the Otaria, • Proc. Zool. Soc.' 1860, p. 108. l\fr. R. Brown, on the P. groenlandica, ibid. 1868, p. 417. Sec nlso on tho colours of seals, Desmarest, ibid. p. 243, 240. |