534 The Descent of Man. Tari II. 



the female is said to be a little more red than the male. Of the 

 Rodents Dr. Gray remarks : " African squirrels, especially those 

 " found in the tropical regions, have the fur much brighter 

 " and more vivid at some seasons of the 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, because, from their unusually bright colours, 

 they best exhibit this difference. The female of the Mus minutus 

 of Russia is of a paler and dirtier tint than the male. In a large 

 number of bats the fur of the male is lighter than in the female. 21 

 Mr. Dobson also remarks, with respect to these animals : " Dif- 

 " ferences, depending partly or entirely on the possession by the 

 " male of fur of a much more brilliant hue, or distinguished by 

 ' ' different markings or by the greater length of certain portions, 

 " are met only, to any appreciable extent, in the frugivorous bats 

 " in which the sense of sight is well developed." This last 

 remark deserves attention, as bearing on the question whether 

 bright colours are serviceable to male animals from being orna- 

 mental. In one genus of sloths, it is now established, as Dr. Gray 

 states, "that the males are ornamented differently from the 

 " females— that is to say, that they have a patch of soft short 

 "■ hair between the shoulders, which is generally of a more or less 

 " orange colour, and in one species pure white. The females on 

 " the contrary, are destitute of this mark." 



The terrestrial Carnivora and Insectivora rarely exhibit sexual 

 differences of any kind, including colour. The ocelot (Felts 

 partialis), however, is exce}^tional, for the colours of the female, 

 compared with those of the male, are " moins apparentes, le 

 " fauve etant plus terne, le blanc moins pur, les raies ayant 

 " moins de largeur et les taches moins do cliametre." 22 The 

 sexes of the allied Fells mitis also differ, but 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, sometimes differ considerably in colour, and 

 they present, as we have already seen, other remarkable sexual 

 differences. Thus the male of the Otaria mgrescens of the 

 southern hemisphere is of a rich brown shade above; whilst the 



Oc the Didelphis, Desmarest, United States,' 1869, p. 207. Mr. 



'- Mammalogie,' p. 256. Dobson on sexual characters in the 



20 ' Annals and Mag. of Nat. Hist.' Chiroptera, ' Proc. Zoolog. Soc ' 

 Nov. 1867, p. 325. On the Mus 1873, p. 241. Dr. Gray on Sloths, 

 minutus, Desmarest, ' Mammalogie,' ibid. 1871, p, 436. 



p. 304. 22 Desmarest, ' Mammalogie,' 1820, 



21 J. A. Allen, in ' Bulletin of p. 220. On Felis mitis, Rengger. 

 Mus. Comp. Zoolog. of Cambridge, ibid. s. 194 



